The optimal window for
growing rice in cool climates is narrow, and temperatures outside of
these windows represent critical lower thresholds that prevent rice
from producing a high yield. Ongoing global warming may widen
this window in areas with a cool climate, and could increase productivity
as a result of increased radiation capture by the canopy.
Shimono et al. (2010) analyzed historical changes in the rice cropping
schedule by farmers in the Hokkaido and Tohoku regions of
northern Japan, two of the northernmost rice growing areas in the
world, and found that the transplanting date had advanced from
the 1960s to the 1980s in response to temperature increases, but
found no further changes thereafter despite apparently increasing
temperatures, indicating a potential for increasing rice productivity
by adopting earlier planting. In addition, the extended growth
duration might allow late-maturing cultivars to increase their
productivity through increased radiation capture (Nemoto et al.,
2011).