Sep 1, 2014

Explaining Extreme Events of 2013 from a Climate Perspective

by
American Meteorological Society, Bulletin of the American Meteorological Society
  • States that attribution of extreme events is a challenging science and one that is currently undergoing considerable evolution
  • In this report, 20 different research groups explored the causes of 16 different events that occurred in 2013
  • The findings indicate that human-caused climate change greatly increased the risk for the extreme heat waves assessed in this report.
  • Finds that how human influence affected other types of events such as droughts, heavy rain events, and storms was less clear, indicating that natural variability likely played a much larger role in these extremes
  • Multiple groups looked at both the Australian heat waves and the California drought, providing an opportunity to compare and contrast the strengths and weaknesses of various methodologies
  • Finds there was considerable agreement about the role anthropogenic climate change played in the events between the different assessments
  • States that this year three analyses were of severe storms and none found an anthropogenic signal
    • Notes, however, that attribution assessments of these types of events pose unique challenges due to the often limited observational record
    • States that when human-influence for an event is not identified with the scientific tools available to us today, this means that if there is a human contribution, it cannot be distinguished from natural climate variability