[ti:Climate Change May Turn Africa’s Dry Sahel Green] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.12]The Sahel is one of driest areas in Africa, but that may change [00:06.76]if Earth's surface temperatures rise more than two degrees Celsius. [00:14.24]Scientists say the Sahel could turn greener, with more plant life, [00:20.40]because the higher temperatures would lead to more rainfall. [00:26.56]More than 100 million people live in the Sahel. [00:32.16]It stretches coast to coast [00:34.75]-- from Mauritania and Mali in western Africa [00:39.12]to Sudan and Eritrea in the east. [00:43.68]The Sahel extends to the southern edge of the Sahara desert. [00:49.80]In recent years, the area has experienced worsening extreme weather. [00:56.76]That includes more droughts -- periods of little or no rainfall. [01:04.32]Some scientists are very concerned about pollution from greenhouse gases [01:10.80]- gases that trap heat in Earth's atmosphere. [01:15.88]They warn that if such gases continue to increase with no limits, [01:21.88]rising temperatures could change weather systems in the Sahel and other areas. [01:29.96]Scientists say this is possible if surface temperatures rise [01:34.96]more than two degrees Celsius above average temperatures [01:40.48]before the industrial revolution. [01:44.60]Some weather models predict a small increase in rainfall for the Sahel. [01:52.36]But there is a risk that the entire weather pattern [01:57.32]will change by the end of the century. [02:01.72]That is the opinion of researchers at the Potsdam Institute for Climate Impact Research. [02:09.80]The size of the possible change is "mind-boggling," [02:14.72]says the institute's Anders Levermann. [02:18.64]"This is one of the very few elements in the Earth system [02:23.32]that we might witness tipping soon." [02:27.32]Levermann also works for Columbia University in New York City. [02:33.56]If the Sahel receives more rainfall, [02:36.96]it will mean more water for agriculture, industry and personal use. [02:44.84]But in the first few years leading up to more rain, [02:49.60]the area is likely to experience very erratic weather. [02:55.12]That may mean extremely dry periods followed by destructive floods, [03:02.16]the researchers said. [03:05.44]They added that because it is hard to know what will happen when, [03:11.88]it makes it hard for people to plan for these changes. [03:18.40]Levermann said any extreme change would create a huge challenge to the Sahel. [03:26.52]More than 100 million people who may be affected already [03:32.20]face many "instabilities, including war," he said. [03:38.40]The area faces many conflicts, including some driven by groups [03:45.84]such as Boko Haram and al Qaeda in the Islamic Maghreb. [03:52.08]The researchers studied rainfall in the Sahel [03:56.80]during the months of July, August and September. [04:01.84]That is the time of year when the area gets most of its rain. [04:08.08]There are a number of possible outcomes, [04:11.24]which depend on the climate that eventually develops... [04:16.00]and whether people in the Sahel are prepared for changes, [04:20.92]said scientist Jacob Schewe. [04:24.28]"Climate change from burning fossil fuels [04:27.76]"really has the power to shake things up," [04:31.60]he told the Thomson Reuters Foundation. [04:36.96]A report on the study was published this month in Earth System Dynamics, [04:43.44]a journal of the European Geosciences Union. [04:49.60]I'm Dorothy Gundy. 更多听力请访问51VOA.COM