The study finds likely human influence in both the extent and likelihood of spring and summer U.S. heat waves last year.
“High temperatures, such as those experienced in the U.S. in 2012 are now likely to occur four times as frequently due to human-induced climate change,” a summary states.
“Approximately 35 percent of the extreme warmth experienced in the eastern U.S. between March and May 2012 can be attributed to human-induced climate change,” states NOAA's summary of the report titled "Explaining Extreme Events of 2012 from a Climate Perspective."
Elsewhere, it notes low Arctic summer sea ice from a warmed atmosphere and ocean that “cannot be explained by natural variability alone.” And climate change made extreme rainfall in Australia and New Zealand more likely, the report finds.
But in contrast, scientists don’t lay several other events at the feet of human-induced climate change.
Climate change had “little impact” on last year’s central U.S. drought. And July 2012's extreme rains in North China and southwestern Japan were “mainly” due to natural variability, researchers found.
Check out the report here.