May 31, 2017

Human-induced changes in the distribution of rainfall

Aaron E. Putnam, Wallace S. Broecker
Science Advances
  • Considers three ways in which planetary warming might influence the global distribution of precipitation:
    • Rainfall in the tropics could increase and the subtropics and mid-latitudes could become more arid
    • Earth’s thermal equator, around which the planet’s rain belts and dry zones are organized, could migrate northward
    • Both of these scenarios could play out simultaneously
  • Reviews paleoclimate evidence from the last glacial maximum, the Bølling-Allerød climatic transition, and the Little Ice Age
  • Inspects more recent trends in seasonal surface heating between the hemispheres over the past several decades
  • Concludes that during boreal summer, in which the rate of recent warming has been relatively uniform between the hemispheres, wet areas will get wetter and dry regions will become drier
  • Concludes that during boreal winter, rain belts and drylands will expand northward in response to differential heating between the hemispheres