Climate change was responsible for 35 percent of extreme warmth experienced in the Eastern US between March and May though it had little impact on the lack of precipitation in the Central US, a new study reveals.
In a new study compiling 19 separate studies on 12 extreme weather events of 2012, researchers reported that anthropogenic climate change was a contributing factor in about half of the events.
In addition to Superstorm Sandy and the Arctic sea-ice minimum, the studies analyzed the heat wave and drought that hit the U.S. during the spring and summer of 2012 - the worst drought in the U.S. since the 1950s - as well as droughts in Africa and Europe, extreme precipitation events in Asia, Europe and Australia, and both hot and cold spells in Europe.
Four of the events - the U.S. heat wave, the Arctic sea-ice minimum, and extreme rainfall events in both northern Europe and eastern Australia - were analyzed by more than one team, allowing a comparison of methods and results.
The research teams used various methods, including comparing climate model simulations with and without human factors, and calculating how the probability of a particular extreme event has changed over time, which allowed them to quantify the influence of climate change on the event.
Three teams that examined the U.S. drought and heat wave found that although climate change likely had little impact on the lack of precipitation in the Central U.S., it likely did account for about 35 percent of the extreme warmth experienced in the Eastern U.S. between March and May.
In addition, researchers reported that in the future, high temperatures are likely to occur four times more frequently in an anthropogenically warmed world.
The findings have been published as a special supplement to the Bulletin of the American Meteorological Society.