Responses of rice yields to recent climate change in China: An empirical assessment based on long-term observations at different spatial scales (1981-2005)

This empirical study (i) assessed rice yield responses to recent climate change at experiment stations, in counties and in provinces of China for the period of 1981-2005 and (ii) identified the climatic drivers determining the trend of yields at each spatial scale. Our empirical results, based on 20 experiment stations during study periods of 14-25 years, indicate that rice yields were positively correlated to solar radiation, which primarily drives yield variation. At most stations, yields were positively correlated to temperature and there was no significant negative correlation between them. Therefore, our empirical results argue against the often-cited hypothesis of lower yields with higher temperature. We explain this by the positive correlation between temperature and radiation at our stations. Empirical analysis to yield at a regional scale (20 counties and 22 provinces) indicates a varying climate to yield relationships. In some places, yields were positively regressed with temperature when they were also positively regressed with radiation, showing the similar pattern at above experiment stations. But, in others, lower yield with higher temperature was accompanied by positive correlation between yield and rainfall, which was not happened at stations. We explain this by irrigation water availability, which played a crucial role in determining climatic effects (radiation or rainfall) on yield variability at a regional scale in China. However, temperature's negative effect is still weak at any scale. This study showed how rice yields respond to recent climate change from 1981 to 2005 at station and regional scales in China and identifies the major climatic driver for yield variation. The empirical findings presented here provide a foundation for anticipating climate change impacts on rice production in China. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.