Drought under Global Warming: A Review
Abstract
One of the big concerns associated with global warming is the potential change to land surface moisture conditions that could have a huge impact on agriculture, freshwater resources, and many other aspects of our society and the environment. How drought has changed during recent past and how it might change in the coming decades is increasingly becoming a great concern as global warming continues and more severe droughts are reported in the media. In this presentation, I will provide an overview, based on my own and others' work, of how drought has changed in the last several centuries and during recent decades over many regions around the world based on historical records, and how it might change in the coming decades based on IPCC AR4 model-predicted climate changes. I will present results from analyses of changes in precipitation, streamflow, soil moisture, and (improved) Palmer Drought Severity Index (PDSI) to show that aridity has increased during the last 50-60 years over many land areas, and rapid warming since the 1980s has contributed significantly to this drying. The PDSI (with improved evapotranspiration estimates) calculated from the AR4 multi-model predicted future climate suggests severe drying in the next 20-50 years over most land areas except the northern high-latitudes and parts of Asia. This drying pattern is consistent with other analyses of model-predicted soil moisture and precipitation changes. Although the quantitative interpretation of the future PDSI values may need to be cautious, combined with the other analyses, the PDSI result points to a dire situation with more severe to extreme droughts in the coming decades over the continental U.S., most of Africa and South America, Australia, southern Europe, and western and southeastern Asia. Changes in precipitation play an important role over many land areas, but enhanced evaporation due to increased radiative heating is also a major factor for the model-predicted drying. For more details, see Dai (2011, JGR, 116, D12115, doi:10.1029/2010JD015541) and Dai (2011, Wiley Interdisciplinary Reviews: Climate Change, 2, 45-65).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.H42G..01D
- Keywords:
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- 1616 GLOBAL CHANGE / Climate variability;
- 1812 HYDROLOGY / Drought;
- 1860 HYDROLOGY / Streamflow