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Global Dimming
Taisia Karaseva
Problem: While global warming is heating the planet, an opposing force is keeping it cool: global dimming. Global dimming is a newly-discovered threat that could change our outlook on solving climate problems. It is a major problem and has had catastrophic effects on the planet and will have even worse impact if nothing is done.
Summary: Global dimming was brought to light and accepted only recently. A British scientist named Dr. Gerald Stanhill had recorded the amount of sunlight in Israel in the 1950s to construct an effective irrigation system, according to Suzanne Elston of The Intelligencer, a Canadian publication. He repeated his experiments 20 years later and discovered that the amount of measurable solar radiation hitting the soil had fallen by 22% in those 20 years, according to The Intelligencer.
A German scientist named Dr. Beate Liepert investigated further and discovered that the solar radiation amounts had decreased 9% in Antarctica, 10% in the United States, 30% in Russia, and 16% in parts of Britain in that same time period, according to The Intelligencer. Many disbelieved this because, in theory, a decrease in sunlight should cool the planet, not warm it like was evident.
At the same time, according to The Intelligencer, two scientists, Dr. Michael Roderick and Dr. Graham Farquhar, were looking over records of pan evaporation collected for agricultural purposes in Australia and they saw that the rates had decreased since the 1990s. With further experiments, they discovered that pan evaporation was most affected by the photons in sunlight hitting the water and forcing water molecules into the atmosphere, not by warmth of the climate, according to The Intelligencer. Less sun was hitting the earth. They proved that global dimming was real.
Working separately, an Indian scientist, Dr. V. Ramanathan, was studying the atmosphere over the Maldives. He knew that clouds form when water droplets form around specks of dust or pollen. He discovered that an increase in fossil fuel specks was causing clouds to be denser, thus acting like mirrors, reflecting the sunlight back to space and, acting like an umbrella, shielding the earth from the sun's heat as well, according to globalissues.org.
Using the Maldives data, Dr. Leon Rotstayn from the CSIRO Atmospheric Research Institute concluded that the fossil fuels burned by Europe had dimmed the northern hemisphere and had lead to the altering of the African monsoons and the Ethiopian 20-year famine, which caused over one million casualties, according to globalissues.org. As BBC Horizon Global Dimming documentary said, "what came out of our exhaust pipes and power stations [from Europe and North America] contributed to the deaths of a million people in Africa, and afflicted 50 million more." According to the documentary, when the European Union began using cleaner car exhaust systems, Europe experienced the overheated summer of 2003, where people died from the heat.
Global dimming is also caused by the contrails of airplanes. After September 11th, airplanes were grounded for three days. Scientists rushed to study the effects and concluded that temperatures rose by an average 1 degree Celsius in those three days, according to globalissues.org. Just one factor of global dimming was removed and the result was huge; this showed that global dimming was hiding the true power of global warming, according to the documentary; the predicted 5 degree increase over the next century is now a far underestimate.
The worry now is that if the same effect happens in Asia, the effects would be even more devastating because over 3.6 billion people (1/2 the world) depend on the Asia monsoons, according to The Intelligencer.
The glitch with global dimming is that so far it has protected us from the harmful effects of less toxic gases like carbon dioxide and methane; without global dimming, global warming will start increasing twice as fast as it is now, according to The Intelligencer. If we learn anything from global dimming, it is that the burning of fossil fuels is the root cause of both problems.
If we decided to not fix anything, global dimming would cause health problems, irregular climate patterns, and acid rain, according to globalissues.org.
Trying to fix global dimming alone without reducing and ending greenhouse gas emissions would be a deadly mistake; globalissues.org predicts that irreversible damage is only 30 years away. This will include Greenland ice melting, causing major costal cities to submerge, and drying rainforests, which will burn, thus releasing more greenhouse gases instead of capturing them. The documentary further predicts that vegetation will die more quickly, erosion will transform the landscape, places around the world, such as Britain, will become Sahara-like, and huge stores of methane hydrate, a greenhouse gas eight times stronger than carbon dioxide and stored in the oceans, will be released. It will be too late to fix anything.
Conclusion: I believe global dimming is a major problem that has complicated the approach to improving the environment. Doing nothing will be better in the short run than fixing half the problem. If the world wants to save the environment and itself, everyone must face both global warming and global dimming, and at the same time. I think that it was a driving force to mask the effects of global warming, but the 9/11 and European summer incidents show that it is nothing to fool with. It could be even worse than global warming because it is a silent killer, almost undetected until recently. Our greenhouse gas emissions are making the planet a huge cave: hot and dark. The way out is to cut the greenhouse gases and to end the dirty emissions. That way global dimming will be reduced, but global warming's main cause will also be eliminated. Both negative impacts will be neutralized, thus not giving one a chance to worsen. All this must be done soon because soon there will be no going back. It is terrifying that what we long thought would solve our problems could unmask an even worse killer.
Uncertainty: Like global warming, once thought to be the sole problem, global dimming might not be the only additional force impacting the climate and environment. Everything is interconnected and many other factors might be playing a role. Natural ice age/warming periods might be causing the warming, but the man-made 9/11 and European incidents show that global dimming has some impact at least. There are also few records of past sunlight levels and cloud mirror impacts, so much historical evidence is fairly recent.
Works Cited
Elston, Suzanne. "Global Warming Not the Only Issue Facing Society." The Intelligencer. 26 Apr. 2008. The Intelligencer Canadian Publication. 3 May 2008 http://www.intelligencer.ca/ArticleDisplay.aspx?e=970528.
Global Dimming. Dir. David Sington. 2005. BBC Horizon. 3 May 2008 http://video.google.com/videoplay?docid=-2058273530743771382&q=global+dimming&ei=_9wcSMi7B47k4ALIp4W1AQ&hl=en.
Shah, Anup. "Global Dimming." Global Issues. 15 Jan. 2005. 3 May 2008 http://www.globalissues.org/EnvIssues/GlobalWarming/globaldimming.asp.
Author Site
5/4/2008
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