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Topic 16: Global dimming and Global warming, hazardous effect of green house gases on our planet earth

Global dimming and Global warming, hazardous effect of green house
gases on our planet earth

The scientific word, global
dimming, has contradicted the knowledge, scientific works and explanation of
the said global warming and its alarming efficacy, alertness and global
sensitisation. Global dimming is a scientific research that was not accepted by
scientist. The phenomenon was absolutely confusing and it takes deep scientific
correlation to believe its existence. It is also difficult to place the effect
of the two phenomenon (global warming and dimming) together, and find a balance
point that will be beneficial for human and its environment.

It is ironical to explain, even with
the high felt impact and intensity of the sun on the earth, some scientists have
decided to proof that the sun is losing her power!  This is the basic proof of global dimming.

Global dimming was first
discovered 40 years ago by a British scientist Gerry Stanhill who was trying to
develop irrigation scheme in Israel. The project involves measuring the solar
radiation of the sun. According to Gerry on one of his global dimming
documentary [1], he explained how amazed he was by the result of the repeated
experiment. The result proves a shocking 22% reduction in sunlight radiation
over Israel as compared with his generated result 20 ago. Correlation data
results from other western countries have also proofed the viability of Gerry’s

He published out journals in 2001
explaining this effect, but it was to his disbelieved that scientists could not
reason out the effect just because it contradicts the world wide heavy spending
research on global warming.

To understand the effect of
global dimming, the principal causative agent as explained by environmentalist
is pollution. Air pollution from burning coal, oil and gas flaring and
residues, power stations and nuclear station releases particles of ash, gases
such as carbon dioxide and sulphur compounds to the air space as pollutants.
These gases are the major contributing element of this phenomenon.

 To my little understanding of global dimming,
the causative agent is relative with global warming. The principal pollutants
responsible for global warming (green house gases) are also responsible for
global dimming. Researchers have made us understand the effect of the green
house gases on our planet and its futuristic damages, but for global dimming, how
does this effect works!

Does it imply the sun is losing
her strength while we still experience excessive heat as recorded in some part
of the world (Heat wave in 1980 killed 1250 people and in 1995 killed more than
700 people in USA) [3]!

According to Professor Ramanathan
[1], the director of centre for atmospheric sciences, he further elucidates the
theory that air pollutants in the space are responsible for 10% reduction in sunlight
radiation on earth. He explains the process formation effect of how the
pollutants are attached with water molecules from the cloud. Naturally,
rainfall is produced by attached water vapour on naturally occurring airborne
particles. But in the event where polluted air is dominant in more tiny
particles that would have occurred naturally, they tend to form tiny rain
droplets in the cloud. The formed tiny rain droplets in the cloud therefore
reflect back the radiated sunlight into the space. This phenomenon reduces the
radiation strength of the sun [2]. This is the simple phenomenon of global
dimming. The future hazardous effect of global dimming is eminent than what we currently
perceive. It’s tragic consequences reflect back on past feminine (1984 Ethiopian
famine), lack of rainfall (African rain belt monsoon lost), shift in the
monsoon thereby changing climatic conditions such as the tropical rain belt. (Climate
scientist Dr Leon Rotstayn, explains how the pollution generated from European
countries and north America affected the African monsoon).

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The graph
above shows the average increase rate of temperature anomaly as represented
between 1860 and year 2000. It indicates a spike increase from year 1940 to
year 2000. This is the era of industrialisation that leads to emission of green
house gases [4].

What is the solution to this global
disaster!  The problem, as explained, is regarded
as a man made situation of which the combine effect with global warming will be
extremely dangerous and hazardous to human kinds and other living organisms
that ever existed.

The main solution is to tackle
the root source of pollution in our individual environment and reduce its
drastic effect to the barest minimum.

 Likewise, the said provided solution was
noticed to increase the radiation strength of the sun’s intensity on the earth.
This therefore calls for an increased and alarming global warming situation. Of
the fact, global dimming has been protecting the planet earth from serious
heating effect of global warming. Perfect method to balance the solution effect
with reduced heating that can lead to global warming.

In conclusion, as developing
safety personnel, environmental safety is very important in making the world a
safer and habitable planet to live in.  The major air pollutants that we need to watch
out for in carrying out our daily activities ( industrial and personal) constitute
towards green house effect are the oxides of carbon and sulphur (green house
gases).  The societal safety depends on
us. Let us contribute on this topic for vast understanding of effects of green
house gases on our planet. I will appreciate discussion more on the global
dimming aspect because it is a developing concept.

Thank you.


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Menelaos Michelakis's picture

(Adding information to ADEDEJI KUYE'S post)

The gases that are most responsible for the greenhouse effect are carbon dioxide (CO2), methane (CH4) and nitrogen oxide(N2O). Scientific statistics inform us that around 1850 (pre-industrial era), CO2 concentration was about 285ppm, and in year 2000 about 368 ppm. This means 30% augmentation in only 150 years.

The other anthropogenic gases, are all together responsible for a 75% increase in temperature. The most important gases are CH4 (145% increase) and N2O (14% increase). Halocarbons, such as chloroflurocarbons (CFCs) are also potent greenhouse gases, although are emitted in very small quantities, that are reducing now mostly because of the hole in the ozone layer.

Ozone is another greenhouse gas. When found in the lower atmosphere or in the stratosphere, is not beneficial as in the ozone layer, but harmful. The are other dangerous pollutants, such as SO2 and NOx, that are connected to human activities (fossil fuels), and although the do not increase temperature , affect human health.

Water vapor also plays a very importartant role in the greenhouse effect. Gases like CO2 and CH4 cause increased evaporation of water from the oceans, leading to increased water vapour ib the atmosphere, which thenleads to further warming and further evaporation. A chain reaction !

Consequences - Hazards :

1) During the 21th century, a rise between 1.4 - 5.8 C, is expected.

2)Sea levels will rise, because of the warming of the water masses, which will lead to volume augmentation and partial melting of the ice caps. Coastal land areas beneath the sea lvl are likely to flood, and become usuitable for humans, unless serious action - such as the construction of barrages - takes place.

3) Increased evaporation will lead to increased humidity, in certain areas, which will lead to an increase in deaths and illnesses closely related to these factors.

4) Scientists cannot entirely understand how ecosystems will react because they do not know all parameters involved. We have to do with non-linear systems, and maybe 'the butterfly phenomenon' shows how immature humans are, in order to make money and have fun.

5) Events like El-Nino are expected to become more frequent and persistent.

6) Some animals not able to adapt, may extinct.

7) Some insects such as mosquitoes , and generally pests will be favoured, something that will lead to increase in their populations. This will happen because they will not die during winter. As a conquence illnesses like malaria are likely to spread in certain areas.

These are only some hazards occuring for humanity. The topic is enormous and there is room for many posts, comments and explanations, so please join.

Ref : G.Boyle, B.Everett, j.Ramage (2003), Energy systems and sustainability


victor.adukwu's picture

Global dimming and
Global warming, hazardous effect of green house gases on our planet earth

Global warming and global dimming
are two big issues that have drawn attention in the recent years. Due to
industrial revolution, increase in population, and growing demands of the
people, these issues are booming out. They pose great danger to our earth and
the sole responsibility is in our hands. First, it is necessary to know about
these two phenomenon and how it affects us.

Global Dimming is a phenomenon
that happens due to reduction in the solar rays falling on the earth's surface.
The residues and particulates such as sulfur dioxide, ash, soot (black carbon),
that are produced after combustion of fossil fuels cause global dimming. These
pollutants evaporate and add to the droplets in the cloud. The clouds that contain
the sulfate aerosols (cloud of solid or liquid particles in a gas), have a high
reflective property, due to which they reflect the suns rays that fall on them,
back to the space. Solar rays are very essential for the balance in water
cycle. When the solar rays are reflected back to the space by these
particulates, then what happens? It causes reduction in water vapor content in
the atmosphere, which eventually results in less rainfall.

Global Warming is a phenomenon
caused by increase in the atmospheric temperature of the earth's surface, due
to increase in concentration of greenhouse gases such as carbon dioxide,
methane, nitrous oxide, chlorofluorocarbons (CFC), etc. These greenhouse gases
trap the solar rays and cause temperature rise in the earth's atmosphere. This
process of trapping solar energy is called greenhouse effect. Increase in
population causes demand in energy sources by burning of fossil fuels and
cutting down trees (deforestation) which is major cause for global warming. It
is clear that, burning of fossil fuels directly contributes to global warming
by releasing greenhouse gases, but how does deforestation contribute to it?
Trees and plants take in carbon dioxide and give out oxygen. If these plants
and trees are cut down, the carbon dioxide will remain unused in the
atmosphere, and increase the temperature of the earth's surface, which is
called global warming.


victor.adukwu's picture

Global dimming and Global warming, hazardous
effect of green house gases on our planet earth

Impacts of
Global Dimming

The significant of  rainfall for
our living cannot be over emphasized. The clear-cut effect of global dimming is
'famine' and 'drought'. It was found that, the famines that happened during
1970s and 1980s were a direct effect of rainfall shortage which is a cause of
this phenomenon. Billions of people from all over the world including America,
Europe, Asia, Africa are affected due to it, in the form of famines. Several
areas in North Africa got dried out due to inadequate rainfall. Even though
Africa did not contribute much to it by burning of fossil fuels,
industrialization etc., it was badly affected than any other developed and
developing countries. [Cited 2012 Oct. 9]. Available from
The developed countries such as the United State is affected by acid rain, which
is caused by the aerosols in the clouds. The process of photosynthesis in the
plants can reduce due to shortage of solar rays. The sulphur aerosols when
inhaled, can cause respiratory diseases in human beings.

Impacts of Global Warming

In recent years, we have heard a lot about floods, hurricanes,
tornadoes, droughts, extinction of certain species, earthquakes, etc. Humans
are interfering too much with the nature and act against it in many ways. The
natural balance in the earth is being shaken by our activities and the direct
result is global warming. Glaciers in the polar regions and mountains melt down
and the sea level rises which is all due to increase in temperature, and it
causes floods, and damage to the food crops. Large areas of lands are damaged
permanently due to extraction of fossil fuels from deep underground. This leads
to frequent earthquakes. Ozone layer is a blanket that entirely covers the
earth's surface and protects it from harmful UV (ultraviolet) radiations. The
CFC that is emitted from refrigerators and insecticides, depletes the ozone
layer and makes our earth vulnerable to harmful UV rays. [Cited 2012 Oct. 9].
Available from


The basic difference between the two phenomenon is that, global warming
causes heating effect in the earth's atmosphere, whereas global dimming causes
cooling effect.
Global warming is caused by greenhouse gases and global dimming is caused by
Global warming traps sunlight and global dimming blocks sunlight.
[Cited 2012 Oct. 9]. Available from

Maria Christou's picture

Undoubtedly, global warming has become one of the most
popular issues in the entire world. Scientific communities warn people to take necessary
measures since the danger is rapidly increasing. As humans, there are some simple
things we can do to contribute to the reduction of the global warming effect:

Plant trees to produce more oxygen and
absorb carbon dioxide from the atmosphere

Recycle; use
recycle bins and paper

Use public
transportation or ride a bicycle instead of driving a car to reduce one’s
individual greenhouse emissions. If you really need a car just buy a hybrid or
a more fuel efficient car.

Take responsibility
for your energy use; keep air conditioners, lights, computers and other devices
closed when it’s necessary

Replace old
appliances with new energy efficient appliances

Use compact
fluorescent bulbs instead of a regular light bulb, it reduces greenhouse
emissions by one third

Buy fresh and
local grown products; not only you reduce the carbon from your food but also
you reduce the energy required for your food’s transportation

These steps along with other things
will help reduce pollution, clean the air and the water and keep us and the environment






Menelaos Michelakis's picture

(Adding information to my previous post - more impacts) (Adding information / explaining victor.adukwu's second post)

Additional impacts of greenhouse gases, to humans, ecosystems, economy and water resources (for the upcoming decades - till 2050).

1. Further increase of CO2 concentration (445 - 640 ppm).

2. Due to droughts in certain parts of the world, poor people will become vunerable to increased risk of hunger.

3.Increase of coral bleaching and deaths.

4.Extinction of some endangered species (high confidence), and many others pushed closer to extinction.

5. Ice environments : Extensive sea-ice reduction, harming of wildlife (seals, polar bears, walrus and many other species), combined with ground subsidence.

6. Cereal crop yields decrease in most tropical and subtropical regions.

7. Water resources : Water supply will decrease in many countries, and also water quality will be degraded by higher temperatures, and because of changes in water flow volume. Also water supplies for human use degraded and reduced, because of saltwater intrusion into coastal aquifers due to sea level rise.

Increased water demands for irrigation and drinking due to increased temperatures. Further increase in flood damages and drought events.

8. Energy will increase further (e.g for air-conditioning)

Ref :  G.Boyle, B.Everett, J.Ramage (2003), Energy systems and sustainability

I would also like to make a small comment about Maria's Christou post. It is very important not only to mention the problems but sovling them, so the solutions described are signifigant and need further discussion. I also would like to give emphasis to recycling, which is the most beneficial of all in my opinion, not only because the impacts of the greenhouse gases are reduced but also for the preservation of the mineral resources of the planet. 

Kii Cajetan Barisi's picture

Global dimming is the gradual reduction in the amount of irradiance at the Earth's surface that was observed for several decades after the start of systematic measurements in the 1950s. The effect varies by location, but worldwide it was estimated to be a 4% reduction from 1960-1990. Since then, a very slight reversal in the overall trend has been observed.

It is thought to have been caused by an increase in particulates such as sulfate aerosols in the atmosphere. The switch from a "global dimming" trend to a "brightening" trend in 1990 happened just as global aerosol levels started to decline.

Global dimming has interfered with the hydrological cycle by reducing evaporation and may have reduced rainfall in some areas. Global dimming also creates a cooling effect that may have partially masked the effect of greenhouse gases on global warming.

Deliberate manipulation of this dimming effect is now being considered as a geoengineering technique to reduce the impact of global warming.

It is thought that global dimming is probably due to the increased presence of aerosol particles in the atmosphere caused by human action. Aerosols and other particulates absorb solar energy and reflect sunlight back into space. The pollutants can also become nuclei for cloud droplets. Water droplets in clouds coalesce around the particles. Increased pollution causes more particulates and thereby creates clouds consisting of a greater number of smaller droplets (that is, the same amount of water is spread over more droplets). The smaller droplets make clouds more reflective, so that more incoming sunlight is reflected back into space and less reaches the Earth's surface. These smaller droplets also decrease rainfall.

Clouds intercept both heat from the sun and heat radiated from the Earth. Their effects are complex and vary in time, location, and altitude. Usually during the daytime the interception of sunlight predominates, giving a cooling effect; however, at night the re-radiation of heat to the Earth slows the Earth's heat loss.

The phenomenon underlying global dimming may also have regional effects. While most of the earth has warmed, the regions that are downwind from major sources of air pollution (specifically sulfur dioxide emissions) have generally cooled. This may explain the cooling of the eastern United States relative to the warming western part.

However some research shows that black carbon will actually increase global warming, being second only to CO2. It is believed that soot will absorb solar energy and transport it to other areas such as the Himalayas where glacial melting occurs. It can also darken Arctic ice reducing reflectivity and increasing absorption of solar radiation.

Some climate scientists have theorized that aircraft contrails (also called vapor trails) are implicated in global dimming, but the constant flow of air traffic previously meant that this could not be tested. The near-total shutdown of civil air traffic during the three days following the September 11, 2001 attacks afforded a unique opportunity in which to observe the climate of the United States absent from the effect of contrails. During this period, an increase in diurnal temperature variation of over 1 °C was observed in some parts of the U.S.

Airborne volcanic ash can reflect the Sun's rays back into space and thereby contribute to cooling the planet. Dips in earth temperatures have been observed after large volcano eruptions such as Mount Agung in Bali that erupted in 1963, El Chichon (Mexico) 1983, Ruiz (Colombia) 1985, and Pinatubo (Philippines) 1991. But even for major eruptions, the ash clouds remain only for relatively short periods.


Kii Cajetan Barisi's picture

Possible use to mitigate global warming

Some scientists have suggested using aerosols to stave off the effects of global warming as an emergency geoengineering measure. In 1974, An increase in planetary albedo of just 0.5 percent is sufficient to halve the effect of a CO2 doubling.

The simplest solution would be to simply emit more sulfates, which would end up in troposphere - the lowest part of the atmosphere. If this was done, Earth would still face many problems, such as:

Using sulfates causes environmental problems such as acid rain
Using black carbon causes human health problems
Dimming causes ecological problems such as changes in evaporation and rainfall patterns and photosynthesis rates
Droughts and/or increased rainfall cause problems for agriculture
Aerosol has a relatively short lifetime
The solution actually advocated is transporting sulfates into the next higher layer of the atmosphere - stratosphere. Aerosols in the stratosphere last years instead of weeks - so only a relatively smaller (though still large) amount of sulfate emissions would be necessary, and side effects would be less. This would require developing an efficient way to transport large amounts of gases into stratosphere, many of which have been proposed though none are known to be effective or economically viable.

It has been stated that "Ideas that we should increase aerosol emissions to counteract global warming have been described as a 'Faustian bargain' because that would imply an ever increasing amount of emissions in order to match the accumulated greenhouse gas in the atmosphere, with ever increasing monetary and health costs."



Kii Cajetan Barisi's picture

The positive aspect of Global Dimming is that it covers the drastic effects of Global Warming. It is predicted by the climate change models that the temperature of earth will increase by five degrees by the next century. The issue has currently under estimate the aftermath of Global Warming.

The most critical point in this discussion is the fact that if efforts are made to control Global Dimming than Global Warming will be in turn exposed. the rays of sun can be called back on earth by controlling the emission from industries but it will led to more and more Global Warming as the green house gases are available in abundance in the atmosphere. To enlighten you on the subject let us review the example of Europe in 2003. Europe made efforts to clean the atmosphere from pollutants without keeping in mind the excessive amount of green house gases. As a result, the number of toxic particles reduced where the amount of green house gases remained same. It no doubt decreased the intensity of feminine in Sahel by increasing the amount of rains but it also created the severe heat wave in 2003 that killed thousands of people in Portugal and France and struck the continent with a number of other issues.

Now let us suppose that we do not made effort to control Global Dimming to protect ourselves from Global Warming than the disaster of increasing Global Dimming will not be more than 30 years away. The sea levels will be increased due to the melting ice in Greenland. Moreover the risk of burning will increase due the drying tropical rain forests which will add into the amount of carbon dioxide. In next 100 years, temperature will increase by about 10 degrees. Such warming has never occurred in the history of humans. It will destroy vegetation. Erosion of soil will be increased and food will be no more produced. The affects will be numerous.

The climatologists do not say that this will happen. The only warn us about the up coming troubles which should be dealt in time. Global Dimming and Global Warming are now adjacent and we should plan to tackle both issues simultaneously. If we do not plan to control pollution now than it will be too late for us as the days in 2040s will be drastic. Not only must the increasing amount of pollutants be controlled but also the existing quantity of green house gases. Only then we will be able to continue living on this planet comfortable.

Kii Cajetan Barisi's picture

The affects of Global Dimming are tragic. It has already killed living beings on massive level. The reflecting back of heat has turned the water of northern hemisphere colder. With water's temperature getting down less rain is generated and the required amount of rain is failed to reach The Sahel, Northern Africa. It is now disclosed that the complex famines of 1970s and 1980s were caused by the less number of rains. The BBC documentary concluded that the smoke coming out of power stations and pipes of North America and Europe is responsible for the death of millions of people in Africa while making the life of more than 50 million people miserable. It is estimated that billions of people in Asia will be affected by the Global Dimming. The monsoon rains of Asia provide rainfall to almost half of the world's population. If Global Dimming will be able to decrease the number of rains then half of the world's population (around three billion people) will be starving.

Kii Cajetan Barisi's picture

Main Pollutants and Their Origins
Growing human populations across the world have led to an unprecedented increase in energy demand. This demand is met largely through the use of fossil fuels, coal, oil and natural gas, which release large quantities of pollution into the atmosphere during their extraction and use, i.e., when they are burnt to provide energy. The main pollutants released include carbon dioxide, methane gas, nitrogen oxides, sulfur dioxide and carbon monoxide.

Pollution and Global Warming -- The Greenhouse Effect
The greenhouse effect is a natural process in which energy from the sun is trapped by the Earth's atmosphere, allowing the planet to warm enough to support life, as explained by BBC News. In terms of increases in global warming, the greenhouse gases carbon dioxide, methane and nitrogen oxides are particularly important. A buildup of these gases from human activities, such as burning fossil fuels and deforestation, has led to an intensification of the greenhouse effect, consequently trapping more heat within the atmosphere and heating the planet. It is believed by many scientists, such as those researching for the Intergovernmental Panel on Climate Change (IPCC), that increased greenhouse gas emissions are exacerbating global warming.
Read more: The Effects of Pollution on the Earth & the Increase in Global Warming |
Global Dimming
Another effect of pollution on the Earth is that of global dimming. Global dimming is a process in which airborne particles, released since the start of the Industrial Revolution, gather in the atmosphere and reflect heat back out to space, as explained by the Natural Environment Research Council. This process cools the Earth. However, particle pollution, which forms the airborne particles responsible for global dimming, is being reduced, whereas emissions of carbon dioxide and other greenhouse gases are increasing. Thus, according to one of the world's leading climate modelers, Peter Cox, the cooling effect from one type of pollution will be lost, whereas the heating effect from greenhouse gases is projected to increase, leading to the potential for greater warming.

Other Effects of Pollution on the Earth
In addition to the effects on global warming, pollution has many other detrimental impacts on the environment. Sulfur dioxide, for example, combines with water vapor in the atmosphere to produce acid rain. Acid rain has detrimental effects on rivers, lakes and soils. According to the National Geographic website, the acid rain makes rivers and lakes acidic, causing them to absorb aluminum from the soil, making the water toxic to aquatic animals. Other pollutants, such as nitrogen oxides and volatile organic compounds, can react in sunlight to produce ground-level ozone, a primary constituent of smog, which can have adverse respiratory health effects on humans, as explained by the U.S. Environmental Protection Agency.


Read more: The Effects of Pollution on the Earth & the Increase in Global Warming |

mohamed.elkiki's picture

Actually i don't agree with you all guys because i see that global warming and dimming is not that harmful to the environment. Man has been using earth sources since millions of years and till now the disasters that happens is just related to certain incidents but not as how the man use earth's sources. i mean we have to use oil and gas and coal for energy and if they pollute the environment by certain percent, it's ok as there will be balance from other area. we cant stop using oil or gas or coal because it pollute the environment but we can reduce the hazards that one incident can do in the environment such as Macondo incident But don't tell me to stop using oil or gas or other sources of energy because the environment. Also, in the eighties or before, people started to say that there is global cooling and the world will end and something like that and nothing happened, its all i think just speculation because of certain incident happened and it affected the environment and people start to talk to how this source of energy will affect the life on planet. Even the sources that most of you got information from are not trusted sources and just people talk. Anyway its just my opinion and at last the industry of oil and gas and coal will never stop because of environmental reason, whatever happened because its a big business and many big companies depend on it.

Thank you all for your post and comments. It has been quite interesting to read, and wonder how so much information we have on this topic. Putting in mind we sharing our knowledge and general opinions, it also calls for a debate such as Mohamed has highlighted. I will therefore appreciate if we address Mohameds opinions. I will soon be focusing on effects of global warming and dimming on agriculture.


Thank you all.


Adedeji Kuye 

Maria Christou's picture

Dear Mohamed how can you disagree with all of these? Maybe the
effects from the global warming and global dimming are not so distinctly but there
are definitely long lasting and dangerous.

According to scientists, physical signs that the environment is changing
are all around us.

The biggest valley glacier in South Africa, Argentina's Upsala Glacier and the Rhone glacier in Valais, Switzerland, are now rapidly shrinking.

islands such as
Tuvalu in the
Pacific are in danger as well. The
Intergovernmental Panel on Climate Change (IPCC)
says that during the
following century the sea level will rise by between 9 and 88cm. 

The level
of snowfall is getting lower. For example, in the Mount
Hood in Oregon the
snowfall from 1985 to 2002 was significantly decreased.

These are just some of the many examples that show that the world
is changing.


Just take a look at

Research analyses
by Stanhill et al (2000) using thermopile pyranometers has led to a research conclusion
explaining the percentage reduction of solar radiation reaching the earth in a
decade has assumed to 2.7%. Definitely, this reduction will affect our
agricultural produce. Logically, plants with height will benefits better from
the remaining available sunlight while the short/developing plants struggles to
survive form the scantly dispersed radiation. This gives me a questionable
conclusion how the photosynthesis process in agriculture will be effective for
developing plants. Balancing of carbon assimilation of plant, water loss and
light synthesis for agricultural products have been jeopardised by the
excessive impart of chemical aerosols and green house gases in the atmosphere. Significant
chances in such agricultural produce will therefore affect all other living organisms
and human being who depends on plant for survive. As we all understand that the
production of fossil fuel depends majorly on the plant and organism decay which
therefore forms oil and gas in the future years. If there is reduction in plant
growth leading to famine, how and where will there be more generation of fossil
oil. This will also cause a reduction in oil and gas availability.

The figure above
is extracted from a journal from agricultural and forest metrology, 2001. It explains
the latitudinal distribution of global irradiance and anthropogenic carbon

This proves the
efficacy of this phenomenon, the solution must be immediate and taken very



Menelaos Michelakis's picture

(Adding information to elkiki's post - how the earth's climate has changed over millions of years)

The majority of anthropogenic carbon dioxide emmissions are due to fossil fuel combustion. Some CO2 , is absorbed by vegetation and plants, some is absorbed on land and some is absorbed by ocean.

It would be interesting to know that the synthesis of the atmosphere was not always like today. Millions of years ago, our planet's surface was covered by enormous pine forests and plants that have disappeared, proving that there was much more CO2 than today. Humans would not be able to breath in such an atmosphere. The greenhouse phenomenon, is something recent, and the rise in temperature is important mostly for human scale, and due to human activity.

So, mohamed has a point. But noone here said that we are going to stop burning coal, or any type of fossil fuel, we just try to diminish the CO2 percentage and other greenhouse gases, in the atmosphere. It is very important for humans that live on the planet (human scale). The planet existed and can exist even without us!

The fact is, that we want somehow protect ourselves and control the situation. I think Maria's first post on this conversation about facing the problem was good. Example : If we preserve forests, plant new trees and recycle we have fewer emissions and a cleaner environment. So more posts about solving the greenhouse phenomenon, are to be welcomed

sreehariprabhu's picture





   According to the dangers of both global warming and global dimming,
it is clear that it is not only a threat to people of some part of world or
area but for the entire world. So it is the responsibility of each one of us to
control both of these effects. If we still did not act, it can turn into an
uncontrollable kind of event and turn into a big disaster. One of the
unfortunate incidents from global dimming was the lack of rain over Africa,
causing many deaths there. So if we still allow this to go on, we might have to
see many more unfortunate incidents.

   From what I read and referred, dimming appears to be caused
by air pollution. Burning coal, oil and wood, whether in cars, power stations etc,
produces not only invisible carbon dioxide which is the main reason for global
warming but also tiny airborne particles of soot, ash etc. These particles
reflect sunlight and thus we get less sunlight. At the same time, the
temperature is rising because of the green house effect. The most alarming
aspect of global dimming is that it may have led scientists to underestimate
the true power of the greenhouse effect. If we reduce global dimming, it will
lead to an increase in global warming and vice versa.

   So if we want to tackle this problem, we have to study the
problems well and should find a way to reduce both these by almost equal ratio.
So it is now time to have more and more research on the ways to prevent global
dimming or global warming from happening and save the world from these two big
threats. But the biggest challenge the world must face will be whether to use fossil
fuels, which is the main reason for both the threats. Even though renewable
energy is now booming, none of this is still able to do what fossil fuels can
do. So it will be most challenging part the world will be facing in the coming


Sreehari Ramachandra Prabhu

Emmanuel Mbata's picture

Global warming and Global dimming are two contradictory phenomenon that has left the scientific community confused. The questions asked now is, are we in a global warming world? or a global dimming world? or in both global warming and global dimming world? The scientific communities refuses to believe the existence of the global dimming phenomenon when the report of it was first published. According to the publications, it was said that Israel has 20% drop of sunlight but if truely it was so, Israel should be freezing. The scientific community knew the world was getting hotter due to emissions of CO2 and other green house gases trapping heat in the earth surface there by making it hotter. After thorough investigations, it has been accepted that global dimming does exist and infact it has been protecting us from the effect of global warming. It is now obvious that most predictions made about the future of our planet could be wrong, which do we accept, Global warming? Global Dimming? or Both or The Earth is just experiencing natural changes as it becomes older?





Reference: The Documentary Global Dimming. 

Firstly, I would like to talk about "Effects of Global Warming". It is clear that global warming is not waiting for a far future and it is happening right now. Some effects of global tempreture rising are as follow:

*Ice(including mountain glaciers and ice sheets) all over the world is melting.

*The number of many species is decreasing. Based on a research, the number of one type of penguins on Antractica   has fallen from 32000 to 11000 in a span of 30 years.

*The rise of sea level is growing faster in comparison with last century.

*Some specieslike butterflies,foxes have moved to cooler areas.

*The average recipitation has increased across the globe.

* Hurricanes are likelyto become stronger.

*Some diseases like malaria which is carried by mosquitoes will be spread.

All in all, the ecosystem will be changed by global warming and the more tempreture rises, the more effects we have.


Henry Tan's picture

Anyway, the world weather is getting worse.

charlesggeorge's picture



Yes Tan, on recent studies conducted in different parts of the
world showed that weather is getting worse than ever. Some of the climate
scientists announced that artic ice is shrinking very much faster than before  because of
global warming and also there may be an extreme winter in North America and Europe
in this year .Also, the heating and cooling of the artic sea water will affect
the jet stream which controls the movement of storm systems. When movement
of storm system becomes slow, there will be a condition of same weather for long
period of time in same areas. Also there is an increase of 1.6 degree Fahrenheit
over last decade which increase in temperature which draws more water from the
soil which will lead to moist place will become wetter while dry areas will
become drier in future





Charles george

Msc in Oil and Gas Engg 


Tilak Suresh Kumar's picture

Adding to your reply,

Over the last century, sea levels have risen about 20 centimetres (8 in) further rises of the ocean could threaten the very existence of this island nation, with its maximum natural ground level of only 2.4 metres (7 ft 8.7 in), and averaging only 1.5 metres (4 ft 11 in) above sea level. Eighty percent of the total land mass of the islands is only a metre above mean sea level. The Intergovernmental Panel on Climate Change's (IPCC) 2007 report predicted the upper limit of the sea level rises will be 59 centimetres (23 in) by 2100, and it means most of the republic's 200 inhabited islands will have to be abandoned. At least one study appears to show that the sea level in the Maldives dropped 20–30 centimetres (8–12 in) throughout the 1970s and '80s, although later studies failed to back this up.

In November 2008, President Mohamed Nasheed announced plans to look into purchasing new land in India, Sri Lanka, and Australia because of his concerns about global warming, and the possibility of much of the islands being inundated with water from rising sea levels. The purchase of land will be made from a fund generated by tourism.

The President has explained his grief:

"We do not want to leave the Maldives, but we also do not want to be climate refugees living in tents for decades".


By 2020, Maldives plans to eliminate or offset all of its greenhouse gas emissions. At the 2009 International Climate Talks, President Mohamed Nasheed explained that:

    "For us swearing off fossil fuels is not only the right thing to do, it is in our economic self-interest… Pioneering countries will free themselves from the unpredictable price of foreign oil; they will capitalize on the new green economy of the future, and they will enhance their moral standing giving them greater political influence on the world stage."

Richard Sedafor's picture


secondly, I would like to concentrate on the solution to reduce global warming. What I strongly believe is that the role of human in global warming is so strong.As a result, we -as human- can reduce it.A cited goal is tostablize the GHG(green house gases) concentrations around 450-550 ppm. This quantity is the one at which the most damaging impacts of globalwarming can be avoided.Current GHG concentrations are 380 ppm. Based on scientists' prediction the earth tempreture could eventually rise by 2.5 degres which is too small.As a result, according to IPCC,the amount of GHG emmission should be reduced to 50-80%.For my part, I will try my best to reduce any activity causes GHG emmission to save the globe.


The greenhouse gases have a global warming potential that differs. Water
vapour is shorter lived and because the others are longer-lived their
concentrations are determined by emission and removal rates. These longer-lived
gases have all increased in concentration since the beginning of the industrial
revolution. Methane and nitrous oxide have a higher global warming potential
than carbon dioxide but their overall effect is less because they are present
at much lower concentrations. The fluorinated gases have a very large global
warming potential but a very low concentration to give a small effect overall. The
concentration of carbon dioxide, prior to the industrial revolution in the
atmosphere has been estimated (by analyzing ice-cores) to have been about
270ppm, compared to 380ppm today. For carbon dioxide, deforestation is also
important because plants (particularly forests) absorb carbon dioxide in
photosynthesis more than they produce in respiration. This means that the
natural overall absorption of carbon dioxide reduces with deforestation. Without
any greenhouse gases the earth would be 30
oC cooler and
uninhabitable and the significance of post-industrial revolution increases is
that they have caused an imbalance in recent years. The best current estimate
is that an atmospheric concentration of 450ppm would equate to global warming
of 2
oC, above which dangerous climate changes are predicted.


The three climate changes of greatest concern are:

The melting of polar ice sheets
resulting in a sea level rise of up to 12 metres.

A reduction in the strength of
North Atlantic ocean currents leading to significant cooling in Europe.

Destabilization of methane
hydrates in the oceans leading to substantial methane release.


Okechukwu Chukelu (51231798)

Frixos Karletides's picture

When fossil fuels are burned except from specific
products they emit sub-products like ash, soot and sulphur dioxide. These sub-products
have the ability to condensate clouds and increase their reflective ability. Therefore
less sun radiation can reach the Earth. This phenomenon is called Global
Dimming and influence the earth by reducing its temperature. This is a
significant problem since lowering the earth’s temperature it results to less
rainfall. On the other hand, the greenhouse gases that are emitted by the
combustion of fossil fuels such as carbon dioxide, methane and nitrous dioxide,
have the ability to trap sun’s radiation on the earth and thus increase its
temperature. This phenomenon is called global warming. This increase in
temperature can cause ice polar regions to melt down and therefore raise the
sea level.  Both events are destructive
to earth and can cause serious environmental and ecological harm.

Frixos Karletides

Harrison Oluwaseyi's picture

Global dimming can be defined as
the reduction in the amount of global irradiance i.e. reduction in the amount
of solar radiation reaching the surface of the earth. Measurements of the
global dimming (Eg) didn’t start till the 1950’s; variations have been noticed
for different parts of the world. Over the past four decades a decrease of over
4% has been noticed, scientists have tried to figure out the cause for this
reduction but there have not been able to attribute it to any particular
situation(s), although they have been speculations that it might be as a result
of any or a combination of the following:

1) The increasing amount of
particulate matter, green house gases or aerosols in the atmosphere.

2) Probability of increased
absorption properties of the cloud.

Global warming is said to be the
rise in the average temperature of the surface of the earth. The average temperature
of the earth is about 0.80C, an increase of about two-third of this
value has been recorded for the past two decades. Over the years there has been
several debates if global warming is real or just some cooked up principle by meteorologist
and scientist to explain the recent happens(change in rainfall pattern,
extremely cold conditions experienced during winter, mean temperature during
summer etc) across the earth. Believe it or not global warming is real.

In the 19th century Joseph
Fourier explained the principle of how green house gases absorb and emit waves
from the sun used to warm the surface of the earth. Green house gases generally
include COx, NOx, SOx, CxHy, particulate matter, CFC's, etc. Over the last
three centuries the amount of these gases present in the atmosphere has
increased as a result of technological advancement and population growth over
the ages. The presence of these gases has had adverse effects on man and his
environment which include:

1) Extinction of some rare animal

2) Rise in the normal sea level.

3) Increase in the mean
temperature of the earth causing the decrease in the amount of ice scape.

4) Increasing health issues e.g.
cancer, increase in the amount respiratory diseases, memory loss in child etc

Man is more aware of the effects
and consequences of global dimming and warming, several steps and technologies have
been adopted to reduce the emission rate of these gases.



-G.Stanhill, ‘ Global dimming: A
new aspect of climate change’.

-Stuart D. Jordan, ‘Global
climate change triggered by global warming’.

Omololu Oyebola's picture

Global dimming is simply described as the reduction in the amount of solar radiation reaching the earth. This is caused by the following, increased amount of particulate matter and pollutants such as carbon monoxide, sulphur dioxide and soot. Due to the increase in energy demand, fossil fuel combustion has led to the emission of green house gases which causes global dimming. These subatances coalease with water droplet on the cloud, as the pollution increases more bonds are formed and a reflective layer is formed the impedes solar radiation from reaching the surface of the earth.

The opposite of this phenomena is Global warming, whereby these greenhouse gases, particulate matter envolopes a chamber of the earth, disallowing heat from escaping into the atmosphere. This cause an increase in temperature. GHG traps infrared radiation disallowing its escape to space.[1]

GHG has a alot of detrimental effect on the ecosystem and the planet as a whole.


CO produced as a result of incomplete combustion of fossil fuels, have effect on the circulatory system of human beings, disrupting the heam group in the human blood, they can also slow down reflexes and actions, cause diziness and brief loss in memory[2]

CFC released from aerosols and cooling systems affects the stratosphere and depletes the ozone layer which serves as a protective layer, preventing us from the harmful effect of Ultraviolet radiation from the sun.The long term exposure to UV can lead to cancer.

Global climate change is as a result of GHG which have heat trapping capabilities[3]released to the atmosphere thus raising the world temperature by some degrees.



[1] SPE Conference paper, 'The Enhanced greenhouse effect of climate change, an assesment'

Energy Sources, Part B: Economics, Planning, and Policy, Volume 1, Issue 1, 2006

[2] Brigden, K. and Santillo, D. 2002. Hazardous Emissions from Philippine Coal-Fired Power Plants, Exeter, UK: Greenpeace Research Laboratories, Department of Biological Sciences, University of Exeter

[3]National Geographic;

Elle Allswell David's picture

Global dimming is the gradual reduction
in the amount of global direct irradiance at the Earth’s surface. This is as a
result of man’s activity on planet earth, it is primarily caused as a result of
increase in Particulates in the atmosphere the chief among them being the
Sulphate aerosols.

Its major effect is that it has resulted
in the re-radiation of heat to the earth surface which has slowed down heat
loss from the earth’s surface.

Global warming is the increase in the
average earth’s temperature. This is also as a result of man’s activity on the
planet. There are some gases that are majorly responsible for this increase in
temperature and are referred to as Green House Gases (GHG). They are: water
Vapour, Carbon dioxide, Methane, Chlorofluorocarbon (CFC), HCFC. The effect of
the Global warming has resulted in rise in sea levels, shrinking of Glaciers,
High temperatures, severe rain storms, and droughts.

This has resulted in the depletion of the
Ozone layer and the only home for man is under threat from high Ultra Violate
rays that can no longer be prevented by the Ozone layer as a result of its
depletion. Proper care should be taken to stop these activities that will
result in Global dimming and global warming.



Olamide s Ajala's picture

The natural gas regularly burned and released into the atmosphere during the production of oil and gas amounts to a double damaging consequence against the environment —wasted resources and additional greenhouse gas emissions.
Green house emissions are mainly caused by human activities such as deforestation, bush gas flaring and burning of fossils. Fossil fuels are more like green house gases that create other by-products which are pollutants such as sulphur dioxide, ash and soot. These pollutants also change the properties of the cloud.
Relating the green house gases with the global diming, polluted air results in clouds with larger number of droplets than unpolluted clouds. This makes those clouds reflective i.e. more of the sun’s heat and energy is reflected back into space therefore there will be reduction in heat reaching the earth.
In order words, global warming also is as a result of greenhouse effect.
The effects of the related emission on our planet earth are various human and environmental problems, global warming is one of the major adverse effects among others.
1. Green house emission ENVIRONMENTAL SCIENCE & TECHNOLOGY / DECEMBER 15, 2004 © 2004 American Chemical Society
2. A concise description of the greenhouse effect is given in the Intergovernmental Panel on Climate Change Fourth Assessment Report, "What is the Greenhouse Effect?"

3. The GAO report Natural Gas Flaring and Venting: opportunities to Improve Data and Reduce Emissions can be accessed at www.gao. gov/cgi-bin/getrpt?GAO-04-809.—KRIS CHRISTEN


Giorgos Hadjieleftheriou's picture

Global dimming and Global warming, hazardous effect of green house
gases on our planet earth

One third of the solar energy that reaches the Earth’s
atmosphere is reflected back to space, the rest of the energy absorbed by the
surface. Because Earth is cooler than sun, it radiates back the sun energy in
much more longer wavelengths. This thermal radiation emitted by the land and
ocean, is absorbed by the atmosphere, including clouds and it is radiated back
to Earth (Greenhouse effect).

This phenomenon helps Earth’s surface to warm up. The
natural greenhouse effect makes life as we know it possible because without it
the average temperature at surface would be below freezing point.  What make greenhouse effect dangerous are
human activities. The most common act is the burning of fossil fuels and
deforestation. This kind of activities can produce global warming.

Greenhouse gases: 
most common greenhouse gases are water vapor and CO2. There
are some more gases which are methane, nitrous oxide, ozone and several more
found in the atmosphere.


IPCC, 2007: Climate Change 2007: The Physical Science Basis.
Contribution of Working Group I to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z.
Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge
University Press, Cambridge, United Kingdom and New York, NY, USA

chukwuemeka uzukwu's picture

Global dimming is a recently
discovered phenomenon that reduces the amount of solar radiation reaching
the surface of our planet. There is evidence that increased numbers of particulates in the air
are responsible for global dimming. These pollutants include sulfur dioxide,
ash and soot. These pollutants have increased as the rate of burning of fossil
fuels has increased. These aerosol particles in the atmosphere have been associated with global
dimming. The pollutants form nuclei for cloud droplets. It is thought that the
water droplets in clouds
around the particles. As air pollution increases more particulates are
available for the formation of droplets. This makes them more reflective,
resulting in less solar radiation (sunlight) reaching Earth's surface.

Until quite
recently the main concern with scientists and governments has been o­n the
Greenhouse Gases which have been emitted as a result of burning fossil fuels.
These reduce the amount of radiated heat from the Earth from leaving the
atmosphere. However, the discovery of global dimming provides evidence that the
models for global warming have seriously underestimated the power of global
warming. In effect, the phenomenon of global dimming has masked the overall
effect of global warming.

The effect of
global dimming have led to fears that global dimming has been masking the true
potential of global warming. In effect the observed increases in temperature
have occured as less radiation has been received o­n Earth. At the moment a
number of predictions provide a prediction of 5 degrees increase in temperature
for the next hundred years. Taking into account of global dimming would suggest
that the true power of global warming is much higher than these estimates.

Global Dimming be reduced?

Global dimming can be reduced by cleaning up the emissions from burning fossil
fuels and the emissions from vehicles. However, a focus o­n particulates o­nly would
result in an increased effect of global warming. In essence, the sources of
both greenhouse gases and air particulates must be addressed. It has been
speculated that the heat waves in Europe in 2003, resulting in thousands of
deaths, could have been the result of the action of the European Community to
reduce particulate emissions, without considering a reduction in greenhouse gases.

should we approach a solution to global dimming and global warming?

Climatologists emphasise that the source of global
warming and global dimming must be tackled together. Drastic reductions of the
burning of fossil fuels is required to reduce the effects of greenhouse gases
and the particulates which are giving rise to global dimming. 

YAKUBU ABUBAKAR 51126107's picture

When the issues of climate change and its effect to the environment was raise by the environment watch groups a decade some years back a lot of people does not believe anything like that especially those countries that operate in an environmentally unfriendly manner. Little wonder any time there is International summit on climate change and the way forward either in Vancouver, Durban south Africa name it three is always a stalemate and blame sharing and counter accusation on who is the main culprit.For those who do not believe that the global warming has a lot of effect to our environment then you must have notice on the increase the following:·         High increase in Sea water Level·         Increase in the number of Earth Quakes and Hurricanes·         Reduction on the amount of fresh water on the increase·         Melting of large ice at the arctic on the increase·         Disappearance of certain species of micro-organism etc.So, Global warming is real and its effect to the environment is on the increase and the earlier we start to leave responsibly the better for the future. Big countries like USA, China, India and other developing economies must learn how to cut down their carbon emissions to safe the situations.Yakubu Abubakar


Global warming cannot be said to be real or a fact as the
actual temperature of the world has actual decreased in recent time. Climate
change, on the hand is real and you have gone on to show numerous examples. The
way the earth works is very complex and scientist are still need to gain a
greater understanding of its working.  A
good example of lack of understanding is there the inaccurate predictions of
the global warming using modelling techniques which can be used against the
belief of global warming (rightly or wrongly???) .

Numerous factors can influence climate change which are
beyond human control and might even hide or reduce the impact of human
activity. A good example of this volcano activity. Mt  Pintabuo erupted in 1991 and it has been
suggested that it  reduced the annual
global temperature the following year by 0.1⁰C and 0.2⁰C.

In Summary, the earth is complex and has been around for 4.6 billion years and the climate has changed with ice ages and droughts throughout this period. Species died out before the human activities and how much of this nature and how much of it human's impact which without doubt has had on the earth's habitiats

James Parry

MSc Subsea Engineering

adavis's picture

Maybe I’m a little skeptical but to me this whole thread seems to prove how little we know about predicting climate change and the key variables involved.  Don’t get me wrong.  I’m sure there are a vast number of scientists trying to use scientific methods to make predictions about the climate.  However, I don’t believe our computer/mathematical models are anywhere close to being able to model the vast number of variables that can 

affect the output.  There does seem to be a vast number of indicators which seem to show that the climate is becoming warmer.  However, I’m not sure we know enough to say definitively what is causing the warming.


To me, as engineers, we should all be more skeptical. 


Global warming or climate change is a subject that shows no sign of cooling down. The earth is warming and humans are the major cause. Food and water supply is at risk and this endanger our health and threaten other basic human needs.

Until recently, governments and scientists focused on the greenhouse gases from fossil fuels. These gases reduce the amount of radiated heat from the earth from leaving the atmosphere. The available models for global warming has underestimated the power of global warming due to the discovery of global dimming. 

Global dimming is a phenomenon that reduces the amount of radiation reaching the surface of the earth. There is evidence that pollutants like sulfur dioxide, ash and soot present in the air are responsible for global dimming and these pollutants increase as more fossil fuels are burnt.

The source of global warming and global dimming must be tackled together. Rapid reduction of the burning of fossil fuels is neccessary to reduce the greenhouse gases and the particulates which cause global dimming. 




faizakhatri's picture

Anthropogenic activities of human being by converting naturally occurring fossil to energy generation for better living can create danger for atmosphere and climate. Combustion and processing naturally occurring fossils which generate greenhouse gases (GHG) and CO2 ultimately cause climate change globally. Each year emission in billion tonnes of carbon equivalently in to atmosphere, resulting: global warming, rising sea levels, floods, heat-waves, stronger and more frequent storms, and drought. And we can see much disaster for last few years and numbers of people affected related with this Environmental issues Main source of Carbon emission is because of industrialized burning and transport sector. According to the IPCC, global greenhouse gas (GHG) emissions must be reduced by 50–80%, by 2050 to avoid the dramatic consequences of global warming obviously it is great challenge as inflation rate increases global energy demand will be higher in future and focused largely on reducing emissions of carbon dioxide (CO2) into the atmosphere since Fossil fuels continue needed for maintaining supply energy demand in future and CCS will boost life of power plant and other industrial units like processing plants / refineries that would otherwise be closed due to high levels of emissions CCS may help for implementation of reduction of fossil fuel power station with CO2 capture, with carbon capture and storage options should be consider to avoid CO2 transport. Or another option is Electricity or Hydrogen can be transported to make these emission-free secondary energy carriers to consumers. In this way it seems that moderate additional costs for electricity could allow the implementation of a first level hydrogen transport infrastructure instead of building a CO2 transportation network... In this way, fossil fuels can continue to play a role within a diverse energy mix.


Faiza Khatri

M.Sc oil and gas engineering

Kyeyune Joseph's picture

Global dimming is reduction in amount direct solar radiation at the earth’s surface. This is believed to be caused by increased particulate materials in the atmosphere. Some of these are aerosols like sulphate aerosols and soot from combustion of coal. These reflect sunlight rays back to the atmosphere leading to cooling of the earth surface. Increased particulates lead to water molecules to coalesce around them effectively reducing amount of rainfall experienced.

Global warming is the rise in average temperature of the earth atmosphere as well as that of the water bodies especially oceans. The earth’s mean temperature has increased significantly and projections show unprecedented increase if nothing is done. This increase is caused mainly by Green House Gases (GHG’s) in the atmosphere that destroys the ozone layer which shields the earth’s surface from direct sun radiations. GHG’s are as a result of burning of fossil fuels as well activities like deforestation. Typical GHG’s include water vapour, methane, carbon dioxide, nitrous oxide, and Cyclofluorocarbons (CFC’s) used as refrigerants. Increased population and industrial development have been found to have direct link to global warming since both signify increase in energy consumption thus increased emissions into the atmosphere. Hazardous effects of GHG’s include:

GHG’s do affect precipitation patterns since they cause changes in temperatures especially that of oceans. Consequently, results have been floods and droughts in some parts of the earth.
Rising sea levels is another consequence coming from global warming as a result of GHG’s. This is due to expansion of water levels in oceans and seas as it warms. Closely related is the melting of ice in glaciers. Melting of glaciers has not only caused rising sea levels but also shortages of water supplies in Asia and South America [1].
Abrupt climate changes is another effect of increased GHG’s into the atmosphere. Global warming has contributed to abrupt climate changes to the detriment of agricultural production.  Food insecurity in some areas is the likely effect.
Ocean acidification through taking in of more carbon dioxide from the atmosphere is another hazardous effect of GHG’s. This affects processes by which marine species create shells and plankton’s species that are important to ocean food chains.

In lieu of the above, both dimming and warming of the globe are closely related. Reducing aerosol particulates means dimming reduces but warming increases! However, the most disastrous is global warming. Thus reducing emissions of GHG’s should be a top priority especially in the energy sector. Technologies such as carbon sequestration, emissions trading will be important in this quest.

[1] Global climate change, available at United States global change research programme website.

JIEFU's picture

Global Dimming
Another effect of pollution on the Earth is that of global dimming. Global dimming is a process in which airborne particles, released since the start of the Industrial Revolution, gather in the atmosphere and reflect heat back out to space, as explained by the Natural Environment Research Council. This process cools the Earth. However, particle pollution, which forms the airborne particles responsible for global dimming, is being reduced, whereas emissions of carbon dioxide and other greenhouse gases are increasing. Thus, according to one of the world's leading climate modelers, Peter Cox, the cooling effect from one type of pollution will be lost, whereas the heating effect from greenhouse gases is projected to increase, leading to the potential for greater warming.


Read more: The Effects of Pollution on the Earth & the Increase in Global Warming |

JIEFU's picture

Pollution produced by humans may be seriously weakening the Earth's water cycle - reducing rainfall and threatening fresh water supplies. This is because the energy for the hydrological cycle comes from sunlight. As sunlight heats the ocean, water escapes into the atmosphere and falls out as rain. So as aerosols cut down sunlight by large amounts, they may be spinning down the hydrological cycle of the planet.

Large scale changes in weather patterns may also have been caused by global dimming. Climate modelers speculatively suggest that this reduction in solar radiation at the surface may have led to the failure of the monsoon in sub-Saharan Africa during the 1970s and 1980s, together with the associated famines such as the Sahel drought, caused by Northern hemisphere pollution cooling the Atlantic. Because of this, the Tropical rain belt may not have risen to its northern latitudes, thus causing an absence of seasonal rains.

The 2001 study by researchers at the Scripps Institution of Oceanography concluded that the imbalance between global dimming and global warming at the surface leads to weaker turbulent heat fluxes to the atmosphere. This means globally reduced evaporation and hence precipitation occur in a dimmer and warmer world, which could ultimately lead to a more humid atmosphere in which it rains less.

A natural form of large scale environmental shading/dimming has been identified that affected the 2006 northern hemisphere hurricane season. The NASA study found that several major dust storms in June and July in the Sahara desert sent dust drifting over the Atlantic Ocean and through several effects caused cooling of the waters - and thus dampening the development of hurricanes.

Relationship to global warming

Some scientists now consider that the effects of global dimming have masked the effect of global warming to some extent and that resolving global dimming may therefore lead to increases in predictions of future temperature rise. The magnitude of this masking effect is one of the central problems in climate change with significant implications for future climate changes and policy responses to global warming. We lived in a global warming plus a global dimming world and now we are taking out global dimming. So we end up with the global warming world, which will be much worse than we thought it will be, much hotter.

Possible use to mitigate global warming

Some scientists have suggested using aerosols to stave off the effects of global warming as an emergency geoengineering measure. In 1974, An increase in planetary albedo of just 0.5 percent is sufficient to halve the effect of a CO2 doubling.

The simplest solution would be to simply emit more sulfates, which would end up in troposphere - the lowest part of the atmosphere. If this was done, Earth would still face many problems, such as:

Using sulfates causes environmental problems such as acid rain
Using black carbon causes human health problems
Dimming causes ecological problems such as changes in evaporation and rainfall patterns and photosynthesis rates
Droughts and/or increased rainfall cause problems for agriculture
Aerosol has a relatively short lifetime
The solution actually advocated is transporting sulfates into the next higher layer of the atmosphere - stratosphere. Aerosols in the stratosphere last years instead of weeks - so only a relatively smaller (though still large) amount of sulfate emissions would be necessary, and side effects would be less. This would require developing an efficient way to transport large amounts of gases into stratosphere, many of which have been proposed though none are known to be effective or economically viable.

It has been stated that "Ideas that we should increase aerosol emissions to counteract global warming have been described as a 'Faustian bargain' because that would imply an ever increasing amount of emissions in order to match the accumulated greenhouse gas in the atmosphere, with ever increasing monetary and health costs."



Ekaterina Pavlichenko's picture

The question is really and simply; is global warming anthropogenic? Scientists seems to be finding an agreement on this issue more difficult than proving and agreeing that something needs to be done.

Taken from a purely objective position (if objective is indeed the right word here); if we consider the cycles of the Earth’s climate we are in the hottest period of the interglacial curve which means that we are heading towards an ice age but for us it is difficult to see as our time frame is not the same time reference as the geology of our planet; however the return of ice should arrive within several tens of thousands of years!

So what to do; well considering that the return of ice is supposedly guaranteed, we have to consider how certain is it that man will be here to witness the event! Emotionally driven arguments state that this will only happen with careful planning and a global commitment from all the aspiring nations to limit their outputs of CO2, maybe even to also limit the reasons for this huge output and of course the argument will go that the main reasons are population growth and the associated energy needs of this expanding global population. But these arguments frighten me as there is so much politicking associated with these positions that you really have to wonder what is driving these supposedly ‘inconvenient truths’. As Adavis points out above, I too believe that we really, really need to be a little more skeptical and use our intellect to overcome emotion and concentrate on what, if anything really needs to be done.       

Ekaterina Pavlichenko's picture

As has been mentioned several times already; the dimming creates a cooling effect which is counteracting the greenhouse warming of our climate and it is therefore likely that this effect has partly masked the magnitude of global warming!

From 1950 to 1985, the solar radiation on the surface of the land has decreased from 8% to 30% taking into account regional and seasonal fluctuations. While the African and American continents, the researchers measured a decrease of 15% sunlight, the lowest levels of darkening were measured in northern Europe and Australia and strongest darkening (30%), was measured in Russia!

The main cause (certain political interests would have us believe) of this "global dimming" is the activity of the developed countries that (supposedly) emit continuous ‘micro particles’ in the air. The explanation given is that these micro particles from our factories and the burning of oil in our vehicles, load water droplets into the clouds turning them into real mirrors. Consequently, sunlight is reflected from the cloud layer and less light reaches us. Less light means lower temperatures in some areas of the planet and less evaporation in the oceans.  

This decrease in brightness thereby mitigating global warming shows that we may have underestimated the magnitude of global warming. The situation is so complicated for the human race, since we must apparently not only respond promptly against global warming but also against the global dimming (and the associated cooling).


Savitha Haneef's picture

I am agreeing to your comment.Global dimming is hiding the true powers of global warming.Only dealing with dimming would increase the affect of global warming as happened in Europe .So the root cause of global warming has to be adressed.If not in 30 years time we would be living in a much more warmer planet. 

Global level impacts has to be considered.Apart from the melting of ice in Green land, drying of the tropical rain forest will lead to increased forest fire which again emits more and more CO2 to the atmosphere increasing the global warming.

Also if the temperature rose extensively it would release methane hydrate, contained at the bottom of our oceans, a gas which is 10 times more powerful than CO2 in its green houseeffect whose effects would be devastating.

Savitha Haneef
MSC Safety & Reliability Engineering

Ekaterina Pavlichenko's picture


Ekaterina Pavlichenko's picture


Oluwatadegbe Adesunloye Oyolola's picture

As more heat gets trapped in the Earth, the planet will become extremely warm, which will in turn, lead to weather changes throughout the world. Since the climatic conditions in which we are living are perfect for our survival, any high
increase in temperature can cause drastic changes which can be life-threatening for all living beings on the Earth.


Weather: In some parts of the world, due to rise in the winter and summer temperatures, the weather will become very hot. It may rain more in winters, while summers will become extremely hot. In other parts of the world, the effects may be completely opposite, as some areas may get very warm while other may become very cold. Storms, floods, and droughts are some expected consequences which may affect different areas of the world.

Sea Levels: Increase in the temperature may cause melting glaciers, which will increase the water in the seas and oceans, raising the sea levels up to 20 to 40 cm all over the world. People living near the lower coastal areas of the world, like Netherlands and Bangladesh, will be at a higher risk from flooding. As a result, millions of people may have to leave their homes and large areas of farmland may also get destroyed.

Farming: The changes in the weather may also cause changes in the amount of rainfall in different parts of the world. Some places may get heavy rains while in other places it may not rain at all. Hence, this will affect the crop growth throughout the world, as crops like wheat and rice grow well in higher temperatures, whereas crops like corn and sugarcane may not grow. Therefore, there will be scarcity of food in some parts of the world and people will suffer from hunger.

Plants and Animals: Due to these weather and temperature changes, many plants and animals will not be able to cope up and will die eventually. For example, polar bears and seals will have to search for new homes for hunting and living, if the ice in the Arctic melts. Since natural habitats of plants and animals will get affected, most species may become extinct.

People: Last but not the least, these weather changes will also bring unwanted changes in our lifestyle. The consequences of these climatic variations on human beings depend on how well we adapt ourselves to the changes, and how much we can do to minimize them.

However, by controlling the amount of air pollution production, efficiently using our energy resources, and recycling used materials, we can significantly reduce the
different reasons that contribute to the generation of greenhouse gases, which lead to climatic changes and global warming




Oluwatadegbe A.O

MSc Oil and Gas Engineering

Oluwatadegbe Adesunloye Oyolola's picture

Global temperatures have risen by over 0.7oC in the last 100 years and eleven of the last twelve years (1995-2006) are the warmest on record.  In the UK in 1990s were very warm about 0.6oC warmer than the mean 1961 - 1990 temperature. Warm winters have reduced thenumber of frosts, and the warmer summers have included record hot spells and high sunshine totals.

Let’s now examine how climate change will affect agriculture:

Soil processes

The potential for soils to support agriculture and distribution of land use will be influenced by changes in soil water balance:  

·   Increase in soil water deficits i.e. dry soils become drier, therefore increased need for irrigation but:

·   Could improve soil workability in wetter regions and diminish poaching and erosion risk.


The effect of increased temperature and CO2 levels on arable crops will be broadly neutral:

·  The range of current crops will move northward

·   New crop varieties may need to be selected

·   Horticultural crops are more susceptible to changing conditions than arable crops

·   Field vegetables will be particularly affected by temperature changes

·  Phaselous bean, onion and sweetcorn are most likely to benefit commercially from higher temperatures

·   Water deficits will directly affect fruit and vegetable production

Grasslands and livestock

·   There is unlikely to be a significant change in suitability of livestock for UK systems

·   Pigs and poultry could be exposed to higher incidences of heat stress, thus influencing productivity

·   Increase in disease transmission by faster growth rates of pathogens in the environment and more efficient and abundant vectors (such as insects)

·   Consequences for food quality and storage

Weeds, pests and diseases

Weeds evolve rapidly to overcome control measures, short lived weeds and those that spread vegetatively (creeping buttercup, couch etc) evolve at the greatest rate:

·   Rate of evolution will increase in hotter, drier conditions and in 'extreme years', could lead to some types of herbicide tolerance becoming more common

·   Possible increase in the range of many native pests, and species that at present are not economically important may become so

·   Surveillance and eradication processes for other significant pests, such as the Colarado beetle will become increasingly important


Food for thought…Should farmers take into account predicted climate changes when 'planning for the long term future' of their businesses?




Oluwatadegbe A.O

MSc Oil and Gas Engineering

Tianchi You's picture

The first effect on climate change by human activity is resulted from
greenhouse gases. As greenhouse gases have the ability to provide an entrance
for sunshine to pass through and warm the earth, these gases including CO2,
CFCs and CH4; however, these greenhouse gases will definitely cause
climate issues once they were over released. With the rapid development of
economy and manufacturing, people still have a high dependence on traditional
forms of fuel like oil and gas which will produce considerable amount of CO2
and other kinds of greenhouse gas. According to the analysis has been done
by Lorius et al(1990), there were 25 percent more carbon dioxide and 100
percent more methane in the atmosphere than Ice Ages (as cited by Pakemham.K.J
2007). As a result, there may be extremely serious consequences result from the
excessive emission of greenhouse gases which are obstacles to keeping the
climate balanced. When too much CO2 is released into the atmosphere,
it does affect the temperature which may melt the iceberg and improve the sea
levels. For example, Bangladeh which is an island nation located between
Pacific and Caribbean, was suffered from the flood in 1991. Due to the
destructive effect, millions of people had no choices but to abandon their
(2007) ). Not only there
will be significant problems on economy, but also people’s lives may be in
danger because of the serious impacts due to climate change. Since the
greenhouse gases are able to keep the atmosphere warm, the temperature may be raised
to a serious level which will be dangerous to the agriculture. For instance,
there is a study from Schneider(1989) predicting that a 3-degree Celsius rise
in temperature in the western and the Great Plains may cause 33 per cent of
reduction in the available land for agriculture(as cited by  Pakemham.K.J
(2007)); therefore, people may face the consequence of


Tianchi You


Oil&Gas engineering 


(2007). Making Connections. Cambridge University Press.

United  Nations 
Environment  Programme 
World  Meteorological  Organization 

Tianchi You's picture

As I have published before, I think human activity is the main reason of the global warming. Here is another human activity which results in global warming.

In addition to deforestation, which can also have a significant effect on climate change. Plant, which has the ability to absorb the carbon dioxide and produce oxygen; however, deforestation has reduced the intake of CO2 which means the natural’s capacity to absorb the CO2may be decreased. Furthermore, the deforestation will also raise the serious problem such as soil erosion. Because of the massive soil erosion, there may be a considerable decrease in water capacity and huge output of CO2 from underground. In addition, there will be a large amount of CO2 released into the atmosphere when people burn the useless branches of the tree. For example , in 1987, the burning of Amazon rainforest in Brazil produced more emissions of carbon dioxide than the entire US’s whole year emissions(as cited by Pakemham.K.J(2007) ). It can be seen that the deforestation does raise many issues which all of them may have negative effects on climate change; however, the trend of deforestation may still at an unsatisfactory level. In order to improve the phenomenon of deforestation, there will be large amounts of money needed to help some countries which have over deforested. As those countries are almost developing or undeveloped countries such as India and Africa, the government and public may have a low awareness of protecting the forest in the process of improving the economy. For example, according to the data from MacNeil(1989), there was 72 percent of forest had been lost since the turn of the century in India(as cited by Pakemham.K.J(2007) ). As a result, it can be seen that deforestation does contribute to the climate change. 


Tianchi You


Oil&Gas engineering 


Pakenham.K.J (2007). Making Connections. Cambridge University Press.United  Nations  Environment  Programme World Meteorological  Organization 

ZHANGYANAN's picture

Topic 16: Global dimming and Global warming, hazardous effect of green house gases on our planet earth
Greenhouse gas

Global warming and global dimming refer to the raise temperature in the earth the atmosphere and the ocean, and also the visible light reduces in a period of time. It mainly refers to the human activity factors causing the phenomenon. Worldwide recognized the main reason for getting warm is caused by the excessive greenhouse gas emission.

A data showed that the temperature of the earth has increased for 5 degrees since the Industrial Revolution 200 years ago.

The impact of the increasing in greenhouse gases on the climate and ecosystem is a more complex problem. Although the increasing carbon dioxide can bring benefits to the photosynthesis of the green plants to more productions, it may cause the changes of the temperature and precipitation.

Also, it may change the primary productivity of the ecosystem and agricultural land carrying capacity. This indirectly effect on the ecosystem and agriculture may much more than the influence on the plants photosynthesis by carbon dioxide directly.

The preliminary studies have shown that global warming and dimming will cause northward of the temperate zone with the motion of atmospheric; as well, it will lead to corresponding changes of the precipitation in the world. In general, the existing low latitudes rain with precipitation will increase, high latitudes will have a heavier snowfall in winter, and the mid-latitudes will have a lower precipitation in summer. For most of the arid and semi-arid areas, the increasing precipitation is favourable. But in the areas with decreasing rainfall will become much more arid and the water will be more tense in summer.

It is estimated that, under the comprehensive consideration premise of the seawater thermal expansion, the increasing of polar precipitation lead to the increased Antarctic ice cap and the snow melts in the Arctic and alpine areas, when the temperature will rise 1.5-4.5 degree while the sea-level may rise to 20-165 cm. It will undoubtedly change the coastline that may bring a tremendous impact to the coastal areas. Also, the low altitude coastal areas will face the challenge of being flooded. Furthermore, sea level rise will cause the coastal flooding and land salinization.



IPCC Fourth Assessment Report, Table 2.14, Chap. 2, p. 212.

Shindell, Drew T. (2005). "An emissions-based view of climate forcing by methane and tropospheric ozone". Geophysical Research Letters 32 (4): L04803. Bibcode 2005GeoRL..3204803S. doi:10.1029/2004GL021900.



Zhang Yanan        ID: 51233945


Kwadwo Boateng Aniagyei's picture

A high majority of the posts on this blog have exposed the
dangers surrounding global warming and global dimming. We have all realized its
effects on the weather, living organisms, sea levels, agriculture and a host of
issues. Should we allow this to continue? A big “NO”. The entire world
agrees that something needs to be done about this growing canker that is affecting
climatic patterns and a number issue as have been previously discussed by most
of my colleagues. However, the road towards controlling global warming and
global dimming has indeed been a difficult one.

The first stumbling block, however, has been trying to get
an agreement on a framework. In 1988, the Intergovernmental Panel on Climate
Change (IPCC) was created by the United Nations Environment Programme (UNEP)
and the World Meterological Organization (WMO) to assess the scientific
knowledge on global warming. The IPCC concluded in 1990 that there was broad
international consensus that climate change was human-induced. That report led
way to an international convention for climate change, the United Nations
Framework Convention on Climate Change (UNFCCC), signed by over 150 countries
at the Rio Earth Summit in 1992. Thereafter, several mechanisms have been
proposed to control the effects global warming and global dimming.                                                                                              

Climate justice and equity: This
notion of climate justice is typically ignored by many rich nations and
their mainstream media though these nations contribute most to greenhouse gases
emissions. This principle recognizes that industrialized nations have emitted
far more greenhouse gas emissions (even if some developing nations are only now
increasing theirs). Rich countries therefore face the biggest responsibility
and burden for action to address climate change; and therefore must support
developing nations adapt—through financing and technology transfer, for

Flexibility mechanisms: Flexibility mechanisms were defined in the
Kyoto Protocol as different ways to achieve emissions reduction as part of the
effort to address climate change issues. This fall into the following
categories: Emissions Trading, Joint Implementation and Clean Development

Carbon sinks and forests: This mechanism tackles climate change by
soaking up CO2. To aid in this, reforestation, or planting of new
forests, have been suggested. This is a popular strategy for the logging
industry and nations with large forests interests. Though there may be some potential
in this strategy, it cannot be solely effective. Creating new forest areas
would require the creation of entire ecosystems. It is criticized for being a
quick fix that does not tackle the root causes effectively and does not lead
to, or promote actual emissions reduction.

With adherence to these mechanisms and the introduction of improved
methods the world will be able to make the earth a safe haven.




Azeezat's picture

Global Dimming is the gradual reduction in the amount of
global direct irradiance at the Earth's surface. This is said to have been
caused by an increase in particulates such as sulphate aerosols in the
atmosphere due to human action. While Global warming results from the
greenhouse effect caused by excessive amounts of greenhouse gases in the
earth’s atmosphere as a result of fossil fuel burning.

Climate change involves not only global warming but also
global dimming. Climate change causing weather extremes such as heat waves,
reduced precipitation levels and droughts which tend to have significant impact
on global warming and global dimming.

Global dimming interacts with global warming by blocking
sunlight that would otherwise cause evaporation and the particulates bind to
water droplets. Water vapour is the major greenhouse gas. On the other hand,
global dimming is affected by evaporation and rain, which has the effect of
clearing out polluted skies.

It is known that Global Dimming due to aerosol pollution has
been a large factor in the lack of rain over Africa resulting to too many
deaths. As a result much dust is being stirred up there and is blowing out over
the North Atlantic causing cooling of the North Atlantic. Thus, there may be fewer
hurricanes in the North Atlantic. Therefore, it is extremely warm because of
Global Warming during hurricane season; so, hurricanes that make it into the
Gulf are likely to become extremely powerful

Global Dimming causes ecological problems such as changes in
evaporation and rainfall patterns, Droughts or increased rainfall cause
problems for agriculture, vegetation will die off even more quickly, Soil
erosion will increase and food production will fail. It is predicted that in
some years to come a Sahara type of climate could be possible in places such as
England, while other parts of the world would fare even worse.

How to mitigate global warming and global dimming

Some scientists have suggested using aerosols to stave off
the effects of global warming as an emergency geoengineering measure.

In 1974, Mikhail Budyko suggested that if global warming
became a problem, the planet could be cooled by burning sulphur in the
stratosphere, which would create a haze. An increase in planetary albedo of
just 0.5 percent is sufficient to halve the effect of a CO2 doubling

The simplest solution would be to simply emit more sulphates,
which would end up in troposphere - the lowest part of the atmosphere. If this
were done, the Earth would still face many problems e.g. environmental and human
health problems from the acid rain and carbon black soot.

The solution actually advocate is transporting sulphates
into the next higher layer of the atmosphere – stratosphere where only a
relatively small (though still large) amount of sulphate emissions would be
necessary, and side effects would be less. This would require developing an
efficient way to transport large amounts of gases into stratosphere, many of which
have been proposed though none are known to be effective or economically


amaka.ikeaka's picture

In addition to what
Azeezat has said, I would also like to mention that the developing countries
stand to lose more from the adverse effects of global warming with regards to
agriculture than industrial countries. Most of these developing countries are
located in warmer parts of the globe, and hence further warming would reduce
rather than increase their agricultural output. This would in turn affect their
economic market, as agriculture contributes tremendously to their economies.
Global warming would reduce their agricultural yield by speeding the
development process of the crops; and in addition to output reduction,
interfere with the ability of the plants to obtain and utilize moisture.

Farmers would be faced with issues of natural disasters such as
flooding, drought, and hailstorms, destroying their agricultural crops. These
natural disasters and the projected rising human population, will lead to an
increase in demand of staple food like rice, maize, resulting in food shortage,
and price hike around the world.


amir masoud bayat's picture

It is undoubtedly clear that the main reason for increased presence of greenhouse gases in the atmosphere is the fact of industrialization which is a process that relies on burning of gas, oil and coal to produce energy. The effect of global warming on environment and human life are numerous and varied. The main effect is an increasing global average temperature which causes variety negative effects such as rising sea levels and the expansion of the range of tropical diseases. Furthermore, global warming may influence not only human activities but also the ecosystem. For instance, some species are being forced out of their habitats due to changing conditions while others are flourishing. As the climate grows warmer and the causes of global dimming are reduced, evaporation will increase due to warmer oceans. Since the world is a close system, this will cause heavier rainfall and more erosion, and in more vulnerable tropical areas especially in Africa, desertification due to deforestation.References: M.H Syed, M.M Khan, Ebrary, Inc, 2008

Richard Sedafor's picture

I agree with the discussion so far. Indeed global warming is causing the destruction of properties running into billions of US dollars annually. Apart from the animal innocent animal species suffering because of the activities of humans, the human themselves are suffering in a dramatic way.

A recent report by the Kofi Annan thinktank indicated that about 300,000 people die annually as a result of global warming. This is alarming but the report states further that this figure could increase to 500,000 in 2030 if the trend is to continue. [1]. Another article posted that two hundred and twenty-five people died due to heat waves in North America in July 2006 [2].

There must be passionate effort made to save the planet from destruction. If industry allocates more money to research to find more efficient technologies that minimise the release of greenhouse gases, there will be hope for the future. Technologies like Carbon Capture and storage should be encouraged and developed further.




eddy itamah's picture

Global dimming, a phenomenon that leads to huge or substantial reduction in the amount of sun energy reaching the earth's crust. Research and studies have showned that there has beena high rate of decline in the amount of sun's energy hitting the earth's surface dated back from the 60s through to the early 90s, though this dimming generally have strong regional difference across the globe. It is recorded that the southern hemisphere saw modest dimming between the period of 1961 to 1990, which is reported to have continued up till date, while the northern hemisphere has witness a significant reduction of 4 - 8% in global dimming. With this record, it is evident that some parts of the world such as Europe and north America have seen partiall recovery from global dimming (i.e) brightening, while the other regions, like china and india have witness a further in global dimming, although there is mixed decline regionally.

Global dimming has been attributed to air pollution from human activity as against the popular opinion which ascribe gloal dimming as due to changes in the sun's luminosity. For instance, Aerosols which basically form from pollution can directly reflect and absorb radiation before it reaches the planet's surface and make clouds brighter and last longer, which therefore means that the reflect more sunlight.

It is apparent that we cannot totally neglect the possibility that natural changes in the earth climate have contributed to global dimming, but human activity have been widely regarded as the major key player contributing to global dimming, since the effect has been closely correlated to trends in atmospheric pollution by human activity. For example, European and North America clean air legislation in the 1990s corresponded to brightening in these regions. Conclusively, china and india have seen further dimming matching pollution increases from rapid industralization.



eddy itamah's picture

A number of substantial impacts have been thought to result from global dimming. Take for instance, it is evident to masked part of the historical warming to greenhouse gases, as seen in the effect of warming caused by areas which have undergone brightening. However, future global dimming changes is expected to be tied to the emissions of atmospheric pollution.

Global warming which is a resultant effect of greenhouse gas emission is a factor that is generally believed to have more significant impact on global dimming in the future. Atompheric water vapour increase in level as a result of continuous warming of higher level of atmoshpere, which in turn absorbs most of the sun's energy before hitting the surface. In future, if global warming proves to be substantial, widespread dimming by water vapour could be a consequence, though the cooling effect of this would be unlikely to reduce the overall warming trend significantly. 



Leziga Bakor's picture

Global dimming (the gradual reduction in the amount of global direct irradiance at the earth’s surface) and global warming (the rise in average temperature of the earth’s atmosphere) are two of the major hazards of increased concentration of greenhouse gases in the atmosphere. Greenhouse gases are gases in the atmosphere that trap heat and keep the average temperature of the earth surface higher than it ought to be. To maintain a balance in the ecosystem, there is an optimum amount of greenhouse gases that should be in the atmosphere. This amount when increased beyond the average value causes the earth surface to retain more heat than it should. Some activity of man on the earth has rapidly increased the amount of carbon dioxide which is a major greenhouse gas in the atmosphere in recent times and this has led to some undesirable effects. One of the major effects is climate change due to global warming and this has resulted in hazardous effects like flood, increase in sea level, drought, famine, and death of plants and animals.

The greenhouse effect is the term used to describe the
natural process by which the Earth’s atmosphere traps some of the Sun’s energy
which warms the planet’s surface to allowing life to thrive.

(Leeds Metropolitan University, 2010)

Greenhouse gases are water vapour, carbon dioxide, nitrous
oxide and methane. The issues are the alternation of climate change and “global
warming” that has been linked to the production of greenhouse gases by human
activity. The increase industry and the global population has led to greater
consumption of natural resources and will link to increase in release of
greenhouse gases into the atmosphere. For the same reason from the energy being
trapped by the greenhouse the increase in concentration, there is an increase
in temperature which has adverse effect the world. The enhanced greenhouse effect
is predicted casthrophic events such as the following:

Rising sea levels

Destroying habitats and causing extinctions of
20% to 30% of animals and plants.

Increase in major natural disasters


Leeds Metropolitan University lecture notes, 2010

James Parry
MSc Subsea Engineering

Acidification of
the Oceans

The atmosphere’s carbon dioxide levels do not match the
carbon dioxide that have released. The carbon dioxide an emission into the
atmosphere is believed to absorbed by the ocean, which have altered the ocean’s
pH levels to become acidic.

The carbon dioxide absorbed has been absorbed by the oceans.
Magistrate association (2009) believes  
that the between 1751 and 1994 that there has been increase in of
acidification by 20%. Since 1994 though 
Magistrate association  believes
that acidification has accelerated and has increased by 30% from the pre-1971
levels and has a strong correlation to the acceleration in carbon dioxide
emissions from an increasing global population and an increase  in 
resource consumption.

The acidification will have a large impact on the ecology of
the oceans. Micro planktons and corals for example are large significant to the
ecology of the oceans and are very sensitive to chemical changes and have
numbers have reduced by as much 33% in the recent years.  There reduction in numbers will impact the
food chain and the biodiversity in the world’s oceans.





James Parry
MSc Subsea Engineering

The enhanced greenhouse effect  is only theory of why climate change is
occurring and that human contribution is greatly over calculated. Climate
changes has been a nature process that 
has occurred throughout the earth’s history. The fluctuation in solar
activity (radiation) is one of the main causes in the fluctuation of global
temperatures seen over the earth’s history.  The theory involving sunspots can also explain
climate change. Sun spots are in 11 year cycle and change where the sunrises
and therefore alters the climate. 

period of diminished solar activity between 1645 and 1715, sunspots were rare
on the face of the sun, sometimes disappearing entirely for months to years. At
the same time, Earth experienced a bitter cold period known as the "Little
Ice Age."

(Science Daily, 2009)

The theory has been linked to past events and could used to
explain the global warming in the 20th century and now the reduction
in temperatures in the 21st Century.


Other research shows that the variance in carbon dioxide is
also a nature process in which part of the earth’s nature cycles. The Antarctic
Ice Core Data in the link below shows the varying levels of carbon through earth’s history.






James Parry
MSc Subsea Engineering

Is Global Dimming Masking The Effects Of Greenhouse Gases

dimming is the interaction with sunlight of microscopic aerosol particles from
human activities. Aerosols reflect and absorb sunlight, reducing the intensity
of sunlight at ground level.”

Office, 2011)

quantity of aerosols particles into the atmosphere from human activities has
increase as global development has increased. 
dioxide, dust and nitrogen oxide are all examples of aerosols. Once in the
atmosphere the aerosols can influence the sunlight in various ways. The first
impact is directly absorb or reflect the sunlight. The second is the aerosols
impact on clouds. The aerosols can 
change the physical characteristics of the cloud which can have a longer
life span and cloud height which increase the amount of sunlight reflected.


increase in amount of sunlight being reflected from global dimming is believed
to  have reduced the impact of global
warming of green house gases. Figure 1 shows the calculated impact of aerosols
and greenhouse gases on global temperature.












(Met office, 2007) The impact of greenhouse gases

 and aerosols on global










James Parry
MSc Subsea Engineering

ROHIT NAIR's picture

Global warming is a global phenomenon that is responsible for
increasing the surface temperature of earth. The green house gases produced during
the burning of fossil fuels are primarily responsible for the increase in
temperature. These gases trap the heat in the earth’s atmosphere and prevent
the cooling of surface. This has eventually resulted in the melting of ice
caps, which has eventually resulted in the increase of sea level resulting in
the flooding of low-lying areas around the world.  It also increases the ocean temperature
resulting in the depletion of algae on its surface, which also acts as a food
source for the fishes.  This affects
smaller fishes and their life expectancy, as they do not have food to
survive.  So its an important phenomenon
and we need to evaluate it closely since it has a potential impact on the food
chain , other than the increase in temperature.

Rohit C Nair
Subsea Engineering
Student id- 51231896

Mehran Vakil's picture

Global dimming is the phenomenon caused by emitting carbon dioxide and also by product of combustion fossil fuels. Pursuant to emitting these types of gas to the atmosphere, the quality and feature of the clouds will be changed. That is why the sunlight does not touch the surface of the Earth and reflects by the clouds. Imagine there is no sufficient sunlight beam. Imagine the shortage of heat and brightness. What will be occurred? Taking into account of these contributing factors, we will face to the lack of vaporization of sea water, after that we can find out inadequate raining fall. At the end of that, we suffer from famine. I am sure, now all of us discover the reason of widespread hunger in Africa (BBC, 2005 cited in Solarpowernote).
Greenhouse gas emission due to burning fossil fuels and the other conventional ones, remain at the top of the atmosphere. They prevent heat from escaping the atmosphere, and trap it. Hence, the Earth becomes warmer gradually (National Geographic, 2012). The risks associated with global warming are divided into many aspects. Being reduced the number of arctic species and also amphibians as an ecological result. Coastal flooding and famine are undesired consequences for humanity. And also depletion of ozone layer as an environmental side effect (Wang and Chameides, 2005).
And now, I get confused. Eventually, combustion of fossil fuels and greenhouse gases emission such as CO2 as well as NOx are responsible for which one??? Global warming or Global dimming?

1)FARIDI, R. 2008. Global Warming: Definitions,Causes,Trends, Effects and Climate Change [Online]. Available: [Accessed 25/11 2012].
2)GEOGRAPHIC, N. 2012. Causes of Global Warming [Online]. Available: [Accessed 25/11 2012].
3)WANG, J. & CHAMEIDES, B. 2005. Global Warming’s Increasingly Visible Impacts [Online]. Available: [Accessed 25/11 2012].

Global dimming and Global warming are two contradicting ideas aimed at explaining the changing world around us. Global dimming which was first noticed in Israel about 40yrs ago during by Gerry Stanhill during his irrigation experiments noticed a 22% reduction in the sun's radiation when compared to the past 20 years. The reasons he gave for this loss in the sun's intensity on earth was pollution.
Global warming on the other hand explains that the recent climatic changes experienced in the world today are as a result of an increase in the intensity of the sun and a damaged ozone layer caused by pollution.
Although contradictory, the two theories are agreed on the fact that the actions of man as related to carbon emissions pose a threat and danger to the planet. Therefore efforts need to be made to control the activities leading to carbon emissions and other harmful processes. Be it carbon emissions trading or carbon taxing, whatever the case may be we need to learn to be more responsible towards the earth we live in and imbibe a culture of sustainable energy living for the sake of posterity.

Kuma Mede

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