Human contribution to precipitation extremes


By definition, climate change happens over the long term — temperatures, precipitation, and wind shift daily, but long-term patterns become clear only after decades or even millennia. Long-term change can be indicated by short-term weather events, however, in particular the frequency and severity of storms or droughts.

A 2011 study published in Nature, “Human Contribution to More-Intense Precipitation Extremes,” combined observational and model-based data to explore how human-induced increases in greenhouse gases have contributed to increased weather extremes.

The study’s major findings include:

  • Human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of data-covered parts of Northern Hemisphere land areas.
  • Observations show overall increasing trends in extreme participation in 65% of North America.
  • Human influence is detectable in the observed temporal or spatiotemporal changes in extreme precipitation over a 40-year period.
  • Strong indicators that the above findings may have underestimated the trend and therefore extreme precipitation events may strengthen more quickly in the future and have more severe impacts than estimated.

The researchers, based at the Climate Research Division of Environment Canada, University of Edinburgh, and University of Victoria, note that the model they used underestimated the observed trend in extreme weather events. Consequently, “extreme precipitation events may strengthen more quickly in the future than projected and that they may have more severe impacts than estimated.”

Tags: disasters, global warming, greenhouse gases

Last updated: April 18, 2011


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Citation: Min, Seung-Ki; et al. "Human Contribution to More-Intense Precipitation Extremes", Nature, February, 2011, Vol. 470, 370-381.DOI:10.1038/nature09763