How Much Would Different Temporal Scales Affect the Pattern of Rice Exposure to Heat Stress in China?

The spatio-temporal pattern of rice exposure to heat stress (EHS) would provide strong supports for decision makers particularly in China, to cope with increasing heat-stress threats under global warming. To obtain reliable assessments, the study period needs no less than thirty years. But how much would different temporal scales affect rice EHS pattern in China? Whether these differences potentially affect adaptation decisions? These problems still remain unclear. Here, we assessed the spatio-temporal patterns of rice EHS at three typical-used scales (1980–2009, 1970–2009 and 1960–2009), and accordingly projected EHS over the 2010s to further explore which scale could better capture recent EHS levels in China. The results showed that in the east of Sichuan Basin and the northwest of the mid-lower reaches of Yangtze River, EHS was highest over 1960–2009, whereas southern China saw highest EHS over 1980–2009. The temporal pattern saw large differences in both the areas with significant trends and their trend levels, showing particular hot spots over 1980–2009. The projected EHS based on the datasets over 1970–2009 were more consistent with those over the 2010s in most cases. Based on the patterns at different temporal scales, adaptation decisions would also show different characteristics, such as more attentions would be paid to the south of Anhui province over the scale of 1980–2009.