Nov 1, 2007
Human Contribution to the Lengthening of the Growing Season during 1950–99
by
,
AMS Journal of Climate
- Carries out an optimal detection analysis to assess the significance of increases in the growing season length during 1950–99, and to measure the anthropogenic component of the change
- Finds the signal is detectable, both on global and continental scales, and human influence needs to be accounted for if it is to be fully explained
- Finds the change in the growing season length is asymmetric and largely due to the earlier onset of spring, rather than the later ending of autumn
- Finds that the growing season length, based on exceedence of local temperature thresholds, has a rate of increase of about 1.5 days decade−1 over the observation area
- Finds that local variations also allow for negative trends in parts of North America
- The analysis suggests that the signal can be attributed to the anthropogenic forcings that have acted on the climate system and no other forcings are necessary to describe the change
- Model projections predict that under future climate change the later ending of autumn will also contribute significantly to the lengthening of the growing season, which will increase in the twenty-first century by more than a month
- Concludes that such major changes in seasonality will affect physical and biological systems in several ways, leading to important environmental and socioeconomic consequences and adaptation challenges