VOA标准英语2010年-Climate Change: New Report Outlines Ho

A new study warns of the potential problems Africa faces from rising temperatures. The Nairobi-based International Livestock 1 Research Institute (ILRI) says the continent must learn to adapt to shorter growing seasons. The report was released as the U.N. Climate Change Conference is held in Cancun, Mexico.

Most warnings about climate change are based on a possible rise in global temperatures by two degrees Celsius 2. But this report considers what might happen if temperatures increased by four degrees.

Institute Director-General Carlos Sere 4 says, "We already know that two degrees Celsius increases are highly probable, even if we get into action. So this study was showing what would happen with scenarios 5 with about four degrees, which are not completely out of the realm of the possible. A number of modeling exercises show that this could happen."Sere says computer models indicate such an increase is possible by the year 2090.

The fate of Africans"The main concern is really the fate of Africans. Africans are, as you know, largely working in rural areas. We estimate at least 60 percent of the total employment is in the rural areas and it's largely in mixed systems – crop/livestock systems where people have small acreages, grow some cereals, some roots and tubers and keep some animals," he says.

A U.N. report predicts a tripling of the population of African cities over the next 40 years. Sere says the population in rural areas will increase as well.

"All our models indicate that the absolute number of people in rural areas is still going to grow. So, farms are going to get smaller. There's going to be less resources. And we'll have to be much smarter in terms of improving the productivity to feed not only people in the rural areas, but those rapidly growing cities," says Sere.

AdaptationScientists at the International Livestock Research Institute say with a four degree Celsius rise in temperature, the growing season in many African countries could dramatically shorten.

"So that would really put large numbers of poor people into a very difficult situation in terms of coping with this change," he says.

Adapting to climate change could mean having diversity in crops and livestock.

Sere says, "Clearly, farmers would have to change some of their crops. So, for example, areas which are getting a reasonable maize 6 harvest, a corn harvest, nowadays, might have to move into more drought tolerant grains like sorghum 7 or millet 8. Similarly, on the livestock side there would have to probably be quite a shift to more hardy 9 local breeds instead of high yielding imported breeds, which are much less able to cope with higher temperatures and more variability."The genetic 10 resources of hardy local crops and livestock could be used to help develop new varieties and breeds better able to deal with climate change.

Sere says the report calls for "sustainable intensification 11.""Finding sustainable ways of better using the resources that we have on the farms. Making sure that, for example, besides using fertilizers, manure 12 is used efficiently 13 to bring those nutrients 15 back into the soil. That crop residues 16 are used smartly to feed animals. We will have to get all these nutrient 14 loops much more efficient than they are today," he says.

He says there would also be "significant changes in disease patterns.""Because," he says, "disease vectors like mosquitoes, like tsetse flies, etc. – the pattern of distribution would change quite dramatically."The Institute says, "While many options are already available that could help farmers adapt.... It is quite possible that the adaptive capacity and resilience of hundreds of millions of people in Africa could simply be overwhelmed by events."The new study appears in the British journal Philosophical 17 Transactions of the Royal Series A.

A minority of scientists dispute the dire 3 predictions about climate change, saying the evidence does not exist and that their computer models show much less dramatic results.