By Niki Morock, Meteorologist
You might recall claims over the recent decades that global warming could increase the number of extreme weather events such as tornado outbreaks, major hurricanes, heavy flooding, and lengthy droughts. While few meteorologists would point to one specific event and claim anthropogenic -- meaning human-caused -- global warming contributed to its severity, somehow the media still made the claim that extreme convective events such as F-5 tornadoes would happen more often and be far more destructive as the earth continued to warm.
The reality is that scientists are still unable to quantatively prove that link between global warming and extreme events on the scale of severe thunderstorms, tornadoes, and even subtropical cyclones. The link to the longer duration events is almost as weak according to some studies. However, it does appear that long-term drought and single-day, extreme rain events are among the few things that may be directly connected to a warmer climate.
A study called "Attribution of Extreme Weather Events in the Context of Climate Change," published last year included this statement:
Confidence in attribution analyses of specific extreme events is highest for extreme heat and cold events, followed by hydrological drought and heavy precipitation. There is little or no confidence in the attribution of severe convective storms and extratropical cyclones.
I will admit that I didn't spend the $79 to buy the paperback version of the report, but instead I read a climate scientist's summary of the report with the conclusion's key points quoted directly. Forgive me. I'm on a tight budget.
Also, I would like to point out the word "confidence" in that statement. There is still some level of uncertainty, but you can have uncertainty and still have a higher level of confidence about some things over others.
Take a look at 2016. NASA reported it was the warmest year on record and the third record-setting year in a row. Yet, NOAA'S Storm Prediction Center produced the infographic below showing lower than normal severe weather reports and watches across the United States. By our standards, it was a pretty quiet year overall for thunderstorms.
Keep in mind that the SPC's purview is hail, high wind, and tornadoes, all of which move thunderstorms up the scale from garden-variety to severe. Flooding and hurricanes are covered by the Weather Prediction Center and the National Hurricane Center, respectively, so they are not included in the SPC's infographic.
My point is to change the perspective of people who still quote those old media suppositions and speculations that global warming will bring more convective storms, bigger tornadoes, and more devastation and destruction from severe weather. Climate change may contribute to some event types and not others, so making a blanket statement regarding all types of weather becoming increasingly worse is dubious at best.