美国一项最新研究成果说，如果将种植其他农作物的耕地改种甘蔗，可有效降低当地气温，减缓气候变化。
美国卡内基学院研究人员17日在英国《自然》出版集团新刊物《自然·气候变化》网络版报告说，他们以甘蔗种植大国巴西约190万平方公里的土地作为研究对象，通过卫星图像分析与温度变化有关的一系列数据，包括气温、植物对阳光反照率以及土壤和植物的水分蒸腾损失总量等。
分析结果显示，如果在原来生长自然植物的土地上改种农作物或牧草，当地气温平均会升高1．55摄氏度；但如果再将农作物或牧草改为甘蔗，当地气温平均会降低0．93摄氏度。
研究人员解释说，甘蔗对阳光的反照率较高，并且可以向周围环境释放水蒸气，因此具有“降温”作用。但他们同时强调，甘蔗的“降温”作用只是相对于农作物和牧草而言，与自然植物相比，它是远不能及的。（生物谷Bioon.com）
生物谷推荐原文出处：
Nature Climate Change doi:10.1038/nclimate1067
Direct impacts on local climate of sugar-cane expansion in Brazil
Scott R. Loarie,1 David B. Lobell,2 Gregory P. Asner,1 Qiaozhen Mu3 & Christopher B. Field1
The increasing global demand for biofuels will require conversion of conventional agricultural or natural ecosystems. Expanding biofuel production into areas now used for agriculture reduces the need to clear natural ecosystems, leading to indirect climate benefits through reduced greenhouse-gas emissions and faster payback of carbon debts1. Biofuel expansion may also cause direct, local climate changes by altering surface albedo and evapotranspiration2, but these effects have been poorly documented. Here we quantify the direct climate effects of sugar-cane expansion in the Brazilian Cerrado, on the basis of maps of recent sugar-cane expansion and natural-vegetation clearance combined with remotely sensed temperature, albedo and evapotranspiration over a 1.9?million?km2 area. On a regional basis for clear-sky daytime conditions, conversion of natural vegetation to a crop/pasture mosaic warms the cerrado by an average of 1.55 (1.45–1.65)?°C, but subsequent conversion of that mosaic to sugar cane cools the region by an average of 0.93 (0.78–1.07)?°C, resulting in a mean net increase of 0.6?°C. Our results indicate that expanding sugar cane into existing crop and pasture land has a direct local cooling effect that reinforces the indirect climate benefits of this land-use option.
