Record-breaking winter snowfalls in the Northeast, flooding in the Mississippi River delta and heat waves in the Southwest have painted a wild picture of extreme weather this year.
On Sept. 7, meteorologists and climate scientists held a telephone conference to discuss any connections this severe weather has had to global climate change.
This year’s extreme weather is unprecedented, according to Jeff Masters, a meteorologist with 30 years experience.
The co-founder and director of meteorology of the weather-focused website Weather Underground, Masters was one of several scientists who released a report to highlight the role of climate change in extreme weather events.
For instance, record snowfalls gave New York two more top 10 snowstorms this year and Philadelphia four of the top 10 snowstorms in the past two years, he said.
In early April, two tornados caused $2 billion in damage, followed by 179 tornados in mid-April, then 336 tornados in late April, he said.
Then on May 22, the Joplin, Mo., tornado resulted in 150 deaths and more than 1,000 people injured, according to the National Weather Service. That tornado is the deadliest one since modern recordkeeping started in 1950 and ranks as the eighth deadliest in U.S. history, according to the National Weather Service.
Then there was the historic flood on the Mississippi River that exceeded the 1927 flood.
After the floods came the heat.
Texas has gone through the hottest temperatures on record, Masters said.
As hurricane season progresses, there have been 13 named storms at the halfway point, he said. On this pace, he said, this season is set to beat 2005 with the most named storms on record. Hurricane season ends Nov. 30.
“Really remarkable,” Masters said of this year’s extreme weather.
Of course, weather has natural extremes, but “We’ve loaded the dice by loading the atmosphere with CO2,” Masters said. “Years like 2011 may become the new normal for the U.S. in the coming decades.”
Many people are asking if these events are connected to climate change, said Richard Somerville, distinguished professor emeritus and research professor at Scripps Institution of Oceanography at the University of California, San Diego.
“The answer is that for many extreme weather events, climate change is an important factor,” Somerville said.
Denver just had the hottest August in the city’s history, according to Jerry Meehl, senior scientist at the National Center for Atmospheric Research.
“People say to me, ‘Heat waves happen all the time.’ And that’s certainly the case, but these have been record-breaking heat waves,” Meehl said.
In the future, Meehl said, there may be more days of record-breaking heat than days of record-breaking lows.
When scientists factor in the amount of heat-trapping gases in their computer climate models, he said, one of the simulations shows that by 2050 the ratio of record-breaking hot days to record lows would more than double, going from 20-1 to 50-1.
“You still have winters in a warming climate,” Meehl said. “We’re just shifting the preference to more record highs rather than record lows.”
There is a difference between weather and climate, said Kevin Trenberth, distinguished senior scientist at the National Center for Atmospheric Research.
“Climate is what you expect. Weather is what you get,” Trenberth said.
In other words, weather is what happens in the atmosphere while climate is what influences what goes on the atmosphere.
He said climate change can account for 5 percent or 10 percent of the influence on weather. These impacts tend to move around.
For example, last year the heat wave was in Russia and this year it’s in Texas and Arizona.
More information is available online at http://climatecommunication.org/.
Amy Wold covers the environment for The Advocate. She can be reached at firstname.lastname@example.org.