>From: Momodou Camara <[log in to unmask]> >Reply-To: The Gambia and related-issues mailing list <[log in to unmask]> >To: [log in to unmask] >Subject: FWD:U.S.pollution behind African drought >Date: Thu, 29 Aug 2002 23:43:38 -0500 > >Via Workers World News Service Reprinted from the Aug. 29, 2002 >issue of Workers World newspaper >------------------------- >U.S. POLLUTION BEHIND AFRICAN DROUGHT >By Gary Wilson > >The African drought from 1970 to 1985 killed 1.2 million people in one >of the most devastating famines ever known. A new study by scientists >from Australia and Canada has concluded that the cause was sulfur >dioxide spewed out by factories and power plants in the United States, >Canada and Western Europe. > >The pollution of North America and Europe disrupted weather patterns, >dramatically changing the temperature of the Earth's surface. This led >to a reduction in rainfall by as much as 50 percent in the Sahel >region of Africa that stretches from Senegal to Ethiopia. > >Tiny airborne particles called sulfate aerosols, which are found only >in the highly industrialized countries, boost the number of small >droplets in clouds; researchers have found that this extends the >lifetime of clouds. Some suspect that the particles also make clouds >reflect more sunlight, cooling Earth's surface below, reducing >evaporation, and ultimately decreasing rainfall. > >"Global climate change is not solely being caused by rising levels of >greenhouse gases. Atmospheric pollution is also having an effect," >says Leon Rotstayn, the Australian scientist who headed the study. > >According to Rotstayn, the sulfate aerosol pollution concentrations >are far greater in the Northern Hemisphere, cooling the atmosphere >there more than in the Southern Hemisphere. It is this imbalance that >affects the tropical rain belt. As a result, the tropical rain belt, >which migrates northwards and southwards with the seasonal movement >of the sun, is weakened in the Northern Hemisphere and does not move >as far north. > >The New Scientist magazine quotes another scientific researcher, David >Roberts: > >"It's an effect of the thermal balance between the two hemispheres. >There has to be a rough balance between the north and south >hemispheres--you can't have spare energy in one place or the other. If >the Earth was completely symmetrical, then the point of thermal >equilibrium, where the total energy on either side of a line was >equal, would be the Equator. But because the Northern Hemisphere isn't > the same as the south [because of the vast energy reservoir of the >Pacific, which retains energy more efficiently than land] we find that >the Northern Hemisphere is warmer than the South." > >However, the cooling of the Northern Hemisphere by aerosol pollution >pushes the point of thermal equilibrium south--and with it go the rain >clouds that had covered the Sahel. It may also explain the flooding >rains that are now sweeping southern Africa. > >One change that the researchers cite in the study occurred in the >1980s. At that time, improvements in anti-pollution laws meant that >sulfur emissions dropped because they were blamed for acid rain. >Following that change, the droughts in Africa became less severe. > >With the new understanding of the connection between sulfate aerosol >pollution and rainfall, the position taken by Washington >administrations from George W. Bush to Bill Clinton can no longer be >sustained. Washington had claimed that nothing needed to be done about >global warming because the aerosol pollution cools the Earth. Now it >has been shown that this kind of cooling contributes to changing >weather patterns in ways that are disastrous for millions of people, > just as are the rising sea levels caused by global warming. > >- END - > >(Copyright Workers World Service: Everyone is permitted to copy and >distribute verbatim copies of this document, but changing it is not >allowed. For more information contact Workers World, 55 W. 17 St., NY, >NY 10011; via e-mail: [log in to unmask] > **** > >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >To unsubscribe/subscribe or view archives of postings, go to the Gambia-L Web interface >at: http://maelstrom.stjohns.edu/archives/gambia-l.html >To contact the List Management, please send an e-mail to: >[log in to unmask] > >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~