It’s official: We can now say global warming has made some weather events worse
Source: Washington Post
It’s official: We can now say global warming has made some weather events worse
By Chris Mooney March 11 at 10:10 AM
From Hurricane Katrina to Superstorm Sandy, to last year’s devastating heat wave in India, the question never ceases to arise: Did global warming cause this?
That question has long made scientists squirm. They know the atmosphere is a complicated place. They know weather events are the result of a huge array of factors — like, say, the El Niño event that has been making weather really, really weird lately. And they know their notion of causation itself is far more complex and multifaceted than the colloquial understanding of the term “cause.”
But now, says a new report from the National Academy of Sciences exploring the attribution of extreme events to climate change, scientists can be at least a little bit less conservative about this.
In the past, a typical climate scientist’s response to questions about climate change’s role in any given extreme weather event was “we cannot attribute any single event to climate change,” says the report, which was composed by a committee of 10 scientists led by David Titley of Penn State University. “The science has advanced to the point that this is no longer true as an unqualified blanket statement.”
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Read more: https://www.washingtonpost.com/news/energy-environment/wp/2016/03/11/its-official-we-can-now-say-global-warming-made-some-weather-events-worse/
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March 11, 2016
[font size=5]New Report Says Science Can Estimate Influence of Climate Change on Some Types of Extreme Events[/font]
[font size=3]WASHINGTON -- It is now possible to estimate the influence of climate change on some types of extreme events, such as heat waves, drought, and heavy precipitation, says a new report from the National Academies of Sciences, Engineering, and Medicine. The relatively new science of extreme event attribution has advanced rapidly in the past decade owing to improvements in the understanding of climate and weather mechanisms and the analytical methods used to study specific events, but more research is required to increase its reliability, ensure that results are presented clearly, and better understand smaller scale and shorter duration weather extremes such as hurricanes and thunderstorms, said the committee that conducted the study and wrote the report.
“An increasingly common question after an extreme weather event is whether climate change ‘caused’ that event to occur,” said committee chair David W. Titley, professor of practice in meteorology and founding director of the Center for Solutions to Weather and Climate Risk at the Pennsylvania State University. "While that question remains difficult to answer given all the factors that affect an individual weather event, we can now say more about how climate change has affected the intensity or likelihood of some events.”
Extreme event attribution is a fairly new area of climate science that explores the influence of human-caused climate change on individual or classes of extreme events compared with other factors, such as natural sources of climate and weather variability. The science typically estimates how the intensity or frequency of an event has been altered by climate change and provides information that can be used to assess and manage risk, guide climate adaptation strategies, and determine greenhouse gas emissions targets. For example, in the wake of a devastating event, communities may need to make a decision about whether to rebuild or relocate and need input on how much more likely or more severe this type of event is expected to become in the future.
Some extreme event attribution studies use observational records to compare a recent event with similar events that occurred in the past, when the influence of human-caused climate change was much less. Other studies use climate and weather models to compare the meteorological conditions associated with an extreme event in simulated worlds with and without human-caused climate changes. The report finds that results are most reliable when multiple, different methods are used that incorporate both a long-term historical record of observations and models to estimate human influences on a given event.
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