预测未来40年气候变化对我国玉米产量的影响

Predicting the impact of climate change in the next 40 years on the yield of maize in China

气候变化将对我国农业生产造成重要影响.传统的积分回归模型和最新的气候预测相结合可能适合评估未来气候变化对作物产量的影响程度.本文首先利用积分回归方法建立了我国不同省区玉米产量与气象要素间的相关模型,然后利用最新的气候预测成果探讨了未来40年气候变化对我国玉米产量的可能影响,并分析了其原因.结果表明：如果玉米品种改良以及目前的科技水平发展速度不变,未来40年我国玉米单产将以减产为主,且随时间递增有减幅增大趋势,但一般在5%以内.A2气候变化情景下,除2021—2030年外,我国玉米减产幅度最大的地区为东北,在2.3%-4.2%;西北、西南和长江中下游地区在2031年以后减产幅度也较大.B2气候变化情景下,东北地区在2031—2040年减产幅度最大,达5.3%;其余仍以西南和西北地区减产幅度较大.两种情景下,华北地区减产幅度均较小,一般在2.0%以内,而华南地区几乎不变.A2相较B2情景下,除2021—2030年外,其余年代的绝大多数地区减产幅度均更大.各旬降水量在我国北方地区对玉米产量几乎都为正效应,而各旬温度对我国各省区玉米产量一般为负效应.未来我国各省区玉米减产的主要原因是气温升高,仅个别省份减产与降水量减少有关.不同方法对未来我国玉米产量变化的评估结果很不一致.进一步增强评估准确性一要考虑品种和科技进步因素的影响,二要增强各类评估模型的机理性.

Climate change will significantly affect agricultural production in China. The combination of the integral regression model and the latest climate projection may well assess the impact of future climate change on crop yield. In this paper, the correlation model of maize yield and meteorological factors was firstly established for different provinces in China by using the integral regression meth- od, then the impact of climate change in the next 40 years on China＇s maize production was evalua- ted combined the latest climate prediction with the reason be ing analyzed. The results showed that if the current speeds of maize variety improvement and science and technology development were cons- tant, maize yield in China would be mainly in an increasing trend of reduction with time in the next 40 years in a range generally within 5%. Under A2 climate change scenario, the region with the most reduction of maize yield would be the Northeast except during 2021-2030, and the reduction would be generally in the range of 2.3%-4.2%. Maize yield reduction would be also high in the Northwest, Southwest and middle and lower reaches of Yangtze River after 2031. Under B2 scenario, the reduction of 5.3% in the Northeast in 2031-2040 would be the greatest across all regions. Other regions with considerable maize yield reduction would be mainly in the Northwest and the Southwest. Reduction in maize yield in North China would be small, generally within 2%, under any scenarios, and that in South China would be almost unchanged. The reduction of maize yield in most regions would be greater under A2 scenario than under B2 scenario except for the period of 2021-2030. Theeffect of the ten day precipitation on maize yield in northern China would be almost positive. How- ever, the effect of ten day average temperature on yield of maize in all regions would be generally negative. The main reason of maize yield reduction was temperature increase in most provinces but precipitation decrease in a few provinces. Assessments of the future change of maize yield in China based on the different methods were not consistent. Further evaluation needs to consider the change of maize variety and scientific and technological progress, and to enhance the reliability of evalua- tion models.