Global Dimming
Research Findings for Global Dimming
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Contents
Findings
Global Dimming Resources
http://www.globalissues.org/EnvIssues/GlobalWarming/globaldimming.asp
http://www.pbs.org/wgbh/nova/sun/
http://www.nasa.gov/centers/goddard/news/topstory/2007/aerosol_dimming.html
- There is also an interesting documentary titled "Horizons" that was produced by the BBC
Explanation of Global Dimming
History of Global Dimming
Adam, David. "Goodbye Sunshine." The Guardian. 18 Dec 2003. 30 Mar 2008 <http://www.guardian.co.uk/science/2003/dec/18/science.research1>.
Adam's article gives a detailed summary of who first discovered the idea of global warming, and the different scientists that have published related research since then. Atsumu Ohmura first published research on global warming in 1985, when he recorded that since the 1960's, the amount of sunshine penetrating Europe had declined by 10%. Since Ohmura's article was published, several other research papers were published during the 1990s on global dimming. All of these papers provided additional evidence to support Ohmura's theory. It was reported that sunshine in Ireland was decreasing, both the Arctic and the Antarctic were getting darker and that light in Japan was also decreasing. The most surprising evidence was that levels of solar radiation in the former Soviet Union had gone down almost 20% between 1960 and 1987. Since then, many more scientists have begun their own research around the world, and are continuing to find evidence that supports Ohmura's original claim.
Geneva Granatstein
Explanation of Dimming
Appell, David. "The Darkening Earth." Scientific American. August 2004,p16-18. <http://web.ebscohost.com/bsi/detail?vid=3&hid=116&sid=f8bc64c8-2fca-460f-8a3c-203ad833101b%40sessionmgr107>
Gives a good background behind global dimming. Makes the claim that the amount of solar reduction has been about 2.7% per decade since the 1950s. Aerosols and other particulates/greenhouse gases are the main culprits behind the dimming and lead to more cloud formation which deflects more solar energy each year. This could affect rainfall and farming productivity among other things. This is a news-based article, the author is reporting the facts put forth from the scientific community.
Andrew Kersh
A Rather Scientific Explanation
Chapman, David M. "Global Warming: Are we hiding behind a smokescreen?" Geodate. May 2006, p6-8.<http://web.ebscohost.com/ehost/pdf?vid=5&hid=102&sid=d4808179-702e-4ac4-b52f-4833a9fadf4e%40sessionmgr109>
This article has some interesting tables and discussion of increasing cloud levels around the world, and lots of specific numbers to back up the argument. This is a good source to use for some concrete statistical information.
Andrew Kersh
A Super Scientific Explanation
Kvalevåg, Maria M & Myhre, Gunnar."Human Impact on Direct and Diffuse Solar Radiation during the Industrial Era". Journal of Climate. Oct 2007.p. 4874. <http://proquest.umi.com/pqdweb?index=0&did=1365218991&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1207507405&clientId=10553>
I am not sure if this is of any use to us, but it has some really advanced rhetoric on global dimming and warming. Lots of results of studies as well. It is similar to the above article, but this one is from an academic journal so I believe it to be peer-reviewed and quite reliable.
Andrew Kersh
What is Global Dimming?
"Global Dimming" Climate Change and Global Warming. 15 Janurary 2005. 31 March 2008 <http://www.globalissues.org/EnvIssues/GlobalWarming/globaldimming.asp#Whatisglobaldimming>
This article explains how Global Dimming is the reduction of heat reaching the earth. Fossil fuel use, as well as producing greenhouse gases, creates other by-products. These by-products are also pollutants, such as sulphur dioxide, soot, and ash. These pollutants however, also change the properties of clouds.
Clouds are formed when water droplets are seeded by air-borne particles, such as pollen. Polluted air results in clouds with larger number of droplets than unpolluted clouds. This then makes those clouds more reflective. More of the sun’s heat and energy is therefore reflected back into space.
Molly Stephens
Cause and Effect
Sunshine Levels Diminishing
Chang, Kenneth. "Globe Grows Darker as Sunshine Diminishes 10% to 37%." Common Dreams Newscenter. 13 May 2004. Common Dreams. 30 Mar 2008 <http://commondreams.org/headlines04/0513-01.htm>.
Chang's article was written in 2004 for the New York Times. It addresses the idea that the amount of sunshine reaching earth has diminished anywhere from 10% to 37% in the 20th century. The article's main point is to make the reader aware that many scientists have been studying the dimming phenomenon, and that they are compiling more and more evidence that supports the theory of global dimming. There is also explanation included of how these scientists perform their studies. The article completely supports the scientist's findings and is not an argument for or against global dimming.
Geneva Granatstein
News on Less Rainfall
Tobin, Mary. "Could Global Warming Mean Less Sunshine and Less Rainfall?." Earth Observatory. 20 05 2004. NASA. 4 Apr 2008 <http://earthobservatory.nasa.gov/Newsroom/MediaAlerts/2004/2004052017017.html>.
This article from the NASA Observatory explains in more detail exactly how global dimming is causing the temperatures to change. The clouds produced by man-made pollutants are much more dense and the water residence time has increased because a warmer atmosphere can hold more water. This reduces the amount of rain.
Beth Kirpes
General Dimming Info
Lovett, Richard A. "A Dim Outlook." Weatherwise. Sept/Oct 2004, p17. <http://proquest.umi.com/pqdweb?did=733701731&sid=1&Fmt=4&clientId=10553&RQT=309&VName=PQD>
The most interesting issue this raises is the fact that because of dimming the earth may actually get warmer and drier instead of warmer and wetter. It was thought that global warming would make more rain fall because of increased humidity, but dimming causes slower evaporation of water and the air cannot become humid so easily. This article agrees with the previous one as far as diminishing overall sunlight in the world. It finally mentions a possible link between the dimming effect and reduced monsoon seasons in India. This article is much like the previous one because the author is writing based off of what scientists have to say on the issue.
Andrew Kersh
History of the Effects
"Global Dimming?." RealClimate. 18 Jan 2005. 30 Mar 2008 <http://www.realclimate.org/index.php?p=105>.
This resource is written in a blog form, where one person posted the topic and information they had gathered and then people had the opportunity to post their own opinions as well as additional research. The information originally posted shows the two sides to the topic. Some people are against the idea of global warming, while others are adamant in believing it, so it was very interesting to read their different reasoning. The page brings up the idea that as of yet there is no actual solid explanation for the phenomenon, but brings up many potential answers and theories that are being researched. The page also discusses the possible connection between global dimming and the famines in Ethiopia in the 1980's.
Geneva Granatstein
Discoveries in Global Dimming
"Dimming the Sun" NOVA Science and Programming. 31 March 2008 <http://www.pbs.org/wgbh/nova/sun/dimming.html>
This article was written to summarize the discoveries of global dimming in the 21st century. Air pollution is significantly reducing the amount of sun light that’s hitting the earth, lowers temperatures and hides the warming effects of greenhouse gases. The article sends you to a link of a slide show that shows how global dimming has progressed since the 1800's
Molly Stephens
Effects of Global Dimming
Hayes , Brian J. "Global Dimming: BBC TWO's Horizon series broadcast of 13 January 2005." Transmitting the Wisdom of Ages. 10 2002. Age-of-the-Sage. 6 Apr 2008 <http://www.age-of-the-sage.org/global_dimming.html>.
This article was written in response to the BBC series broadcast, Horizons. This article focuses on the effects of global dimming while also explaining how it works. Some climatologists say that global dimming is helping to cause global warming. Global dimming is caused by tiny particles of soot, ash, and sulphur dioxide that are airborne and absorb tiny particles of rain while then form clouds and reflect the sun's heat back to space. This article suggests that global dimming causes a major change in the climate which accounts for the famine in Ethiopia and the lack of seasonal rains in Sub-Saharan Africa due to altered rainfall patterns. Offers a solution to the problem which is to clean up particle emissions, however, it also states that as global dimming becomes less of an issue that global warming will get much worse because global dimming is masking the intensity of the change in temperatures. It gives examples of places with cleaner air being much hotter.
Beth Kirpes
Link to Global Warming/Controversies
One Interesting Outlook
"What is Global Dimming?" UnlimitedWatts.com. <http://unlimitedwatts.com/listpage.jsp?page=globaldimming>. 30 March 2008.
This is included because of the view it presents in the fourth paragraph. It has some good statements regarding reverting global dimming, and intentional global dimming. This information seemed unique enough to call attention to. I believe this article was written more recently than the previous two, the view seems very liberal and advocates use of "alternative energies and conscientious living" to help offset global warming and dimming. Unlike the other articles, this one gives an opinion on how to stop dimming, whereas the more scientific based ones simply put the facts out there for us to take however we want. This article's purpose is to motivate people to live cleaner to help fix our earth.
Andrew Kersh
A Different Perspective
Spencer, Metta. "Global Dimming or Warming?." Metta Spencer's WebBlog. 16 11 2007. I Power Blogger. 2 Apr 2008 <http://metta-spencer.blogspot.com/2007/11/global-dimming-or-warming.html>.
This a link to a lady's blog so it isn't scientific or anything but she offers a new perspective on the issue that is at least worth looking at. In the beginning, she explains global dimming but then she says that this theory was disproved. That global dimming isn't real. She says that all the pollutant particles in the air aren't masking the heating effects-they are increasing the severity of it. She then tries to explain that the brown clouds full of pollutants vary in content and according to altitude, their effects as well. The water vapor has a cooling effect but the particles contradict it by reflecting light in all directions, including towards space. All the black soot particles in the air heat the atmosphere which only intensifies the heating effect of greenhouse gases.
Beth Kirpes
