Climate Trends since 1980 Have Both Positive and Negative Impacts on Crop Yields in China
A research group headed by TAO Fulu in Institute of Geographic Science and Natural Resources Research, Chinese Academy of Science, found that climate trends during 1980？2008 have had measurable impacts on crop yields in China, with a distinct spatial pattern.
They used improved datasets on both climate and crop production to investigate climate trends during the crop growing period and their impacts on yields of major crops (rice, wheat, maize and soybean) in China by county.
For the entire country, the planting area-weighted average showed that climate trends from 1980？2008 reduced wheat, maize and soybean yields by 1.27, 1.73 and 0.41%, respectively, while increasing rice yields by 0.56%. As a result, climate trends as a whole reduced wheat and maize production by 3.60 × 105 t and 1.53 × 106 t, respectively, and increased rice and soybean production by 7.44 × 104 t and 4.16 × 103 t, respectively.
The estimates of climate impacts are smaller than previous estimates that used different scales, datasets and methods.
The particular crops and regions that have been most affected and should be priorities for adaptation are maize and wheat in arid and semi-arid areas of northern and northeast China, where droughts induced by increases in temperature and solar radiation could limit the benefits of improved thermal conditions.
Climate warming decreases crop yields by accelerating crop development rate, and thus reducing crop growth duration and yield accumulation, and by increasing temperature extremes and heat stress.
In another study, they presented the temporal and spatial changes in occurrence frequency of major rice disasters, including droughts, floods, heat stress, chilling damage, insects and diseases, during the warmer period of 2000–2009, in comparison with the period of 1991–2000, based on both the observed records and the meteorological indexes.
The results showed that changes in rice disasters could be largely ascribed to changes in climate extremes in recent decades. Floods, insects and diseases occurred more frequently at earlier growth stages; in contrast, chilling damage occurred more frequently at later growth stages in southwestern China during the period of 2000–2009, in comparison with the period of 1991–2000.
Related papers：
1. Tao, F., Zhang, Z., Zhang, S., Zhu, Z., Shi, W. 2012. Response of crop yields to climate trends since 1980 in China.Climate Research54:233-247.（http://www.int-res.com/abstracts/cr/v54/n3/）
2. Tao, F., Zhang, S.， Zhang Z. 2012.Changes in rice disasters across China in recent decades and the meteorological and agronomic causes. Regional Environmental Change,2012, DOI: 10.1007/s10113-012-0357-7.
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