一项研究表明，即便是日最低温度少量上升也可能减少几十年后的水稻产量。Jeffrey Vincent及其同事分析了从1994到1999年占全球水稻供应70%的6个亚洲国家的227个灌溉水稻农场收集的数据。这组科学家使用一个回归模型分离出了日最高温度和最低温度的变暖趋势与灌溉水稻产量之间的关系。这组作者说，更高的日最高温度可能稍微增加水稻产量，但是更高的日最低温度具有更强的相反作用。这组科学家提出，适度变暖的净效应将是减少未来水稻产量，因为气候预计表明日最低温度很可能比日最高温度更快地增加。这组科学家还指出，显著变暖有可能带来通过干扰光合作用以及花粉制造从而破坏水稻植株的日最高气温。这组作者说，在这种情境中，更高的日最高温度效应将从好的作用变为坏的作用，并进一步让水稻减产恶化。
论文 #10-01222: "Rice yields in tropical/subtropical Asia exhibit large but opposing sensitivities to minimum and maximum temperatures," 作者 Jarrod R. Welch 等人
媒体联系人：Jeffrey R. Vincent，杜克大学Nicholas环境学院
Nicholas School of the Environment, Duke University, Durham, NC
电话：919-613-8025
电子邮件：Jeff.Vincent@duke.edu
该论文配有图片可供索取
Published online before print August 9, 2010, doi: 10.1073/pnas.1001222107
Rice yields in tropical/subtropical Asia exhibit large but opposing sensitivities to minimum and maximum temperatures
Jarrod R. Welcha, Jeffrey R. Vincentb,1, Maximilian Auffhammerc,d, Piedad F. Moyae, Achim Dobermannf, and David Daweg
+ Author Affiliations
aDepartment of Economics, University of California at San Diego, La Jolla, CA 92093;
bNicholas School of the Environment, Duke University, Durham, NC 27708;
cDepartment of Agricultural and Resource Economics, University of California, Berkeley, CA 94720;
dNational Bureau of Economic Research, Cambridge, MA 02138;
eSocial Sciences Division, and
fOffice of the Deputy Director General for Research, International Rice Research Institute, Los Baños, Laguna 4031, Philippines; and
gAgricultural Development Economics Division, Food and Agriculture Organization of the United Nations, 00153 Rome, Italy
Edited by Gurdev S. Khush, University of California, Davis, CA, and approved July 6, 2010 (received for review January 30, 2010)
Abstract
Data from farmer-managed fields have not been used previously to disentangle the impacts of daily minimum and maximum temperatures and solar radiation on rice yields in tropical/subtropical Asia. We used a multiple regression model to analyze data from 227 intensively managed irrigated rice farms in six important rice-producing countries. The farm-level detail, observed over multiple growing seasons, enabled us to construct farm-specific weather variables, control for unobserved factors that either were unique to each farm but did not vary over time or were common to all farms at a given site but varied by season and year, and obtain more precise estimates by including farm- and site-specific economic variables. Temperature and radiation had statistically significant impacts during both the vegetative and ripening phases of the rice plant. Higher minimum temperature reduced yield, whereas higher maximum temperature raised it; radiation impact varied by growth phase. Combined, these effects imply that yield at most sites would have grown more rapidly during the high-yielding season but less rapidly during the low-yielding season if observed temperature and radiation trends at the end of the 20th century had not occurred, with temperature trends being more influential. Looking ahead, they imply a net negative impact on yield from moderate warming in coming decades. Beyond that, the impact would likely become more negative, because prior research indicates that the impact of maximum temperature becomes negative at higher levels. Diurnal temperature variation must be considered when investigating the impacts of climate change on irrigated rice in Asia.
