NASA Study: Eastern U.S. to Get Much Hotter
Pastor Dale Morgan
May 10, 11:03 PM EDT
*NASA Study: Eastern U.S. to Get Much Hotter*
By SETH BORENSTEIN
AP Science Writer
WASHINGTON (AP) -- Future eastern United States summers look much hotter
than originally predicted with daily highs about 10 degrees warmer than
in recent years by the mid-2080s, a new NASA study says.
Previous and widely used global warming computer estimates predict too
many rainy days, the study says. Because drier weather is hotter, they
underestimate how warm it will be east of the Mississippi River, said
atmospheric scientists Barry Lynn and Leonard Druyan of Columbia
University and NASA's Goddard Institute for Space Studies.
"Unless we take some strong action to curtail carbon dioxide emissions,
it's going to get a lot hotter," said Lynn, now a scientist at Hebrew
University of Jerusalem. "It's going to be a lot more dangerous for
people who are not in the best of health."
The study got mixed reviews from other climate scientists, in part
because the eastern United States has recently been wetter and cooler
than forecast.
Instead of daily summer highs in the 1990s that averaged in the low to
mid 80s Fahrenheit, the eastern United States is in for daily summer
highs regularly in the low to mid 90s, the study found. The study only
looked at the eastern United States because that was the focus of the
funding by the U.S. Environmental Protection Agency, Lynn said.
And that's just the eastern United States as a whole. For individual
cities, the future looks even hotter.
In the 2080s, the average summer high will probably be 102 degrees in
Jacksonville, 100 degrees in Memphis, 96 degrees in Atlanta, and 91
degrees in Chicago and Washington, according to the study published in
the peer-reviewed journal Climate.
But every now and then a summer will be drier than normal and that means
even hotter days, Lynn said. So when Lynn's computer models spit out
simulated results for July 2085 the forecasted temperatures sizzled past
uncomfortable into painful. The study showed a map where the average
high in the southeast neared 115 and pushed 100 in the northeast. Even
Canada flirted with the low to mid 90s.
Many politicians and climate skeptics have criticized computer models as
erring on the side of predicting temperatures that are too hot and
outcomes that are too apocalyptic with global warming. But Druyan said
the problem is most computer models, especially when compared to their
predictions of past observations, underestimate how bad global warming
is. That's because they see too many rainy days, which tends to cool
temperatures off, he said.
There is an established link between rainy and cooler weather and hot
and drier weather, said Kevin Trenberth, climate analysis chief at the
National Center for Atmospheric Research. Rainy days means more clouds
blocking the sun and more solar heat used to evaporate water, Druyan said.
"I'm sorry for the bad news," Druyan said. "It gets worse everywhere."
Trenberth said the link between dryness and heat works, but he is a
little troubled by the computer modeling done by Lynn and Druyan and
points out that recently the eastern United States has been wetter and
cooler than expected.
A top U.S. climate modeler, Jerry Mahlman, criticized the study as not
matching models up correctly and "just sort of whistling in the dark a
little bit."
But Andrew Weaver of the University of Victoria, editor of the journal
Climate but not of this study, praised the paper, saying "it makes
perfect sense."
He said it shows yet another "positive feedback" in global warming,
where one aspect of climate change makes something else worse and it
works like a loop.
"The more we start to understand of the science, the more positive
feedbacks we start to find," Weaver said.
Weaver said looking at the map of a hotter eastern United States he can
think of one thing: "I like living in Canada."
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On the Net:
The NASA paper: http://pubs.giss.nasa.gov/abstracts/2007/Lynn-etal.html