Posted at 6:20 PM on March 21, 2013
by Paul Huttner
Filed under: Climate Cast
Every Thursday MPR meteorologist Paul Huttner joins Kerri Miller on The Daily Circuit for "Climate Cast" on MPR News Stations to talk about the latest research on our changing climate and the consequences that we're seeing here in Minnesota and worldwide.
These days it seems like we are witnessing climate changes unfold right before our very eyes.
It's not our imagination.
The nature of our seasons is changing. Spring blooms come earlier. Summer is more humid with a documented increase in extreme localized flash flood events...and more frequent droughts. Fall lingers longer. Lakes freeze up later. Winters are trending shorter and noticeably, measurably milder. New plants are able to thrive in Minnesota's milder climate.
We're all living witnesses to rapid climate changes in our lifetime. This is no longer your grandparents "Minnesota."
In 2013 at MPR we're devoting more coverage to the science behind and the growing effects of our changing climate in Minnesota and around the globe.
Climate Cast for March 21st, 2013
Superstorm Sandy cost billions of dollars, just in lost economic activity, when it hit the East Coast. It knocked out power to more than 8 million homes. So it's alarming to consider the conclusion of a Danish researcher: that big storms may strike the eastern United States more and more in coming years.
On Thursday's Climate Cast, Kerri Miller and MPR News' Chief Meteorologist Paul Huttner talked about those findings and the outlook for the coming tornado season. Here's an edited transcript of their conversation:
It's common sense.
1) Warm water spawns hurricanes.
2) Warmer water spawns more intense hurricanes.
A new study sifts through some data that shows our warmer oceans may create an exponential increase in the most intense hurricanes, and the storm surge that comes with.
Batten down the hatches, East Coasters: A new study argues that for every one degree Celsius (1.8 degrees F) of global warming, the American Atlantic seaboard could see up to seven times as many Katrina-sized hurricanes.
That's the conclusion of Aslak Grinsted, a climatologist at Copenhagen's Niels Bohr Institute, who led an effort to match East Coast storm surge records from the last 90 years with global temperatures. His results, published today in the Proceedings of the National Academy of Sciences, suggest that the strongest hurricanes are likely to become more commonplace with only half the level of warming currently projected by scientists.
"There is a sensitivity to warming, and it is surprisingly large," Grinsted said.
The study compiled storm surge measurements from tide gauges at six locations on the East and Gulf Coasts, filtering out the effects of seasonal cycles, daily tides, and overall sea level rise to isolate the impact of storms. Next, these records were stacked against both global temperatures and a series of other climatic factors, like natural water temperature cycles and regional rainfall. The result? Global temperatures turned out to be one of the best predictors for hurricane activity. Using computer models, Grinsted found that a one-degree (C) rise in global temperatures could multiply extreme hurricane frequency by two to seven times.
Red represents hurricane projections with one degree (C) global warming; blue represents no warming. The gap between these lines suggests that a warmer climate will produce more frequent hurricanes; the gap is widest at the top, meaning the biggest increase will be with the biggest storms. Image: PNAS
Tornado Season 2013: What can we expect?
The old saying goes like this.
"There is no bad weather, just different kinds of good weather."
It all depends on your perspective.
Last year's Midwest Mega-Drought suppressed thunderstorms...and tornado numbers. That's the "good" side of drought.
But how does climate change affect tornado frequency? Researchers are still trying to find a solid link.
Climate Central's Urooj Raja expands.
Large-scale weather patterns can have a major influence on severe weather outbreaks, and the intense drought that affected the heart of "Tornado Alley" in 2012 acted to squelch severe thunderstorms and tornadoes, since there was such little moisture and atmospheric instability available to produce tornado-forming storms. Tornado-prone states such as Oklahoma and Kansas were in severe to extreme drought conditions during the spring and summer of 2012, and in fact continue to be in drought conditions, according to the latest drought monitor released on March 7. It is quite possible that the lingering drought will affect tornado season in some of the Plains states again this year, unless significant drought relief occurs soon.
How does climate change impact tornado activity? Currently there is no scientific consensus on whether climate change has already altered tornado activity, or whether and how it will in the future. Because of warming air and ocean temperatures, there is already more water vapor available for thunderstorms to tap into, which may lead to more powerful thunderstorm updrafts. Research shows that global warming may increase atmospheric instability in parts of the U.S., increasing overall thunderstorm activity. However, a vital ingredient for tornado formation -- wind shear -- may actually decrease as the climate warms.
NOAA's Deke Arndt explains more on tornadoes in this Extreme Weather 101 piece.
Climate Cast resources:
Want to know more about climate change? Here are few quick links to credible climate change sources.
-NOAA NCDC's "State of the Climate" report
-Great summary of Modern Day Climate Change from SUNY-Suffolk
-Minnesota Climate Working Group climate change resources
-Mark Seeley's Weather Talk
-Common climate change myths
-Climate change in the news from Climate Central
-More coverage from The Yale Forum on Climate Change and Media