Feb 28, 2018

Trends in Weather Extremes

by
Geert Jan van Oldenborgh
,
World Weather Attribution
  • The author's trend analysis shows that almost everywhere heat extremes (defined as the highest daily average temperature of the year) are now warmer than a century ago, following the obvious first-order connection with global average temperature
    • One exception is in the eastern U.S. where heat extremes are npw roughly as warm as they were during the Dust Bowl of the 1930s
  • Finds that cold events (the daily average temperature of the coldest day of the year) heat up even faster than the heat extremes, up to a factor of five times the global mean temperature
  • Looks at the highest daily precipitation of the year as a measure of extreme precipitation and finds that the highest daily mean of the year has increased at more stations than it has decreased
  • Finds that the average global increase in precipitation is similar to the increase of the amount of water the atmosphere can hold at higher temperatures (the Clausius–Clapeyron relation), about 7% per degree Celsius, but local trends are often different from the global average
  • Finds that even if the theoretically expected increase in the most intense tropical cyclones is not yet detectable, their physical impacts have increased substantially already
  • Graphics