Friday, May 1, 2015

Extreme Weather is Already Here and Will Get Worse

Advances in attribution science have allowed researchers to demonstrate that extreme weather is on the rise. A new study links human produced greenhouse gases to increasingly frequent extreme weather events including heat, precipitation and drought. The study shows that anthropogenic extreme weather are already happening and they will get worse as the world warms. The study indicates that global warming is currently responsible for about three quarters of the extreme heat days and around one fifth of extreme precipitation (rain or snow).

The research titled, Anthropogenic contribution to global occurrence of heavy-precipitation and high-temperature extremes, was conducted by E.M. Fischer and R. Knutti and published in Nature Climate Change Letters.

“A lot of us and our colleagues were surprised by how high these numbers are already now in the present day climate,” said Dr Erich Markus Fischer from the Swiss Federal Institute of Technology.

The data from this study suggest that that situation will continue to worsen as the Earth continues to warm. Wet regions will get wetter and dry regions will get dryer.

With 2 Celsius of warming the Earth will have a four of five time greater likelihood of experiencing heat extremes than we do today. Heavy rainfall may increase from around 18 percent today to 40 percent if temperatures rise by 2 degrees Celsius.

Protracted heat waves and prolonged rainy periods, will also occur more often. Tropical countries will experience more than 50 times as many extremely hot days and 2.5 times as many rainy ones. Other dry regions including the parts of the Mediterranean, North Africa, Chile, the Middle East and Australia will experience less heavy rain days.

“With every degree of warming,” the study's authors wrote, “it is the rarest and the most extreme events -- and thereby the ones with typically the highest socioeconomic impacts -- for which the largest fraction is due to human-induced greenhouse gas emissions.”

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