New Research Helps Attribute Specific Extreme Weather to Climate Change

Climate scientists have long been pressed to answer the question "did climate change cause this?" in the days following the most recent devastating weather event. A watershed report (pdf) released Thursday helps those scientists to more conclusively answer: "yes."

The report, authored by the Washington, D.C.-based National Academies of Sciences, Engineering, and Medicine (NASEM), outlines a system to determine which extreme weather events are caused by climate change and to what extent.

This new area of scientific research, called "extreme weather attribution," is more definitively affirming a connection that many have long asserted and perhaps also helping to silence those deniers who claim that catastrophes such as Cyclone Winston are not caused by global warming.

"Like the surgeon general's 1964 report connecting smoking to lung cancer," Heidi Cullen, chief scientist at Climate Central, wrote in an op-ed in the New York Times on Thursday, "the report from the National Academies connects global warming to the increased risk and severity of certain classes of extreme weather, including some heat waves, floods and drought."

The question about how much climate change has caused specific weather events has been a hard one to answer, Cullen noted, partly because so many other factors--natural and human--influence the weather. It's also proved difficult to pin down to what extent climate change is a factor in a single event, when the effects of global warming are so pervasive. The new report, however, offers scientists a definitive method with which to parse out the connections.

"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," NASEM reports in a statement.

The rigorous methodology outlined in the NASEM report will allow scientists not only to link past events to climate change, but also to discern the future risks for climate-caused catastrophe, ideally helping countries and cities at risk to better prepare for those disasters.

The report is timely, as environmentalists have recently raised the alarm about the shockingly quick rise in global temperatures this winter and scientists have discovered that in 2015 carbon dioxide levels "exploded," according to a new report from the National Oceanic and Atmospheric Association (NOAA).

"Climate change can no longer be viewed as a distant threat that may disrupt the lives of our grandchildren, but one that may be singled out as a factor, possibly a critical factor, in the storm that flooded your house last week," Cullen wrote. "The science of extreme weather attribution brings climate change to our doorsteps."