Last updated October 4, 2019

Quantifying the influence of global warming on unprecedented extreme climate events

The world is not quite at the point where every hot temperature record has a human fingerprint, but it's getting close to that.

Noah Diffenbaugh, lead author and Stanford University climate scientist

This is a step forward in that it allows general statements about what fraction of events of the given types selected have a statistically significant

Adam Sobel, a Columbia University climate scientist  who wasn't part of the study


  • Analyzes weather stations worldwide and calculates the global trend in warming that contributed to the record for hottest day of the year in at least 82% of the records for hottest day over the 1961-2010 period, including contributing at least 30% of the magnitude over large areas of Europe and eastern Asia, and increasing the probability by at least a factor of 2.5 over most of Europe and parts of western North America and eastern Asia.
  • Spots climate change's influence 57 percent of the time in records for lowest rainfall in a year and 41 percent of the time in records for most rain in a 5-day period
  • Formally identifies the fingerprint of anthropogenic warming in the observed trend of increasing heat extremes over the western U.S.
  • Applies four attribution metrics to four climate variables at each available point on a global grid
  • Results suggest that scientifically durable operational attribution is possible but they also highlight the importance of carefully diagnosing and testing the physical causes of individual events