“Climate change includes not only changes in mean climate but also in weather extremes,” writes the authors of a new study.
According to the new research, three out of every four extremely hot days are tied to climate. It’s not just the heat either. Researchers also say nearly 20% of extremely heavy downpours can be linked to the overall warming of the Earth.
What about the rest? Those were associated with natural swings in weather.
What constitutes “extreme” for this study? A “moderate” extreme is any extreme weather event that occurs once in 1,000 days. Now, this varies from place to place. A hot day where I live (Alabama), is a bit different than a hot day in Wisconsin.
Just imagine the hottest day you experienced where you lived in the past three years. There’s a 75% chance it was tied to climate change.
Dr. Erich Fischer, from ETH Zurich and one of the authors, writes:
“Not one of these events is solely the direct result of warming, but warming increases their frequency. And the less common and more extreme the hot extreme or heavy rainfall event, the more this can be attributed to a man-made contribution.”
Fischer also notes the differences the world would see between a 1.5 degree Celsius global rise in temperatures and a 2 degree Celsius rise. If temperatures rise by 2 degrees Celsius, researchers expect twice as many extreme heat waves across the world compared to a 1.5 degree Celsius.
What about other extremes like tornados and other severe weather? According to Fischer, “numerous studies on these events do not find a significant increase attributable to climate change.”
It’s difficult to get the data sample size needed to tell if the increase in global temperatures has any effect on severe weather. Fischer mentions how extremes are rare. It took the gathering of data from measuring stations all around the world for researchers to see the changes in extreme weather.
“A clear picture emerges,” writes Fischer. “There has been a global trend towards more frequent and intense hot extremes since the 1950s. In addition, significantly more stations have recorded increases than decreases in heavy precipitation.”