New Study Links Current Events to Climate Change
Seth Borenstein
Published: Aug 5, 2012, 9:51 AM EDT
Associated Press
Associated Press
In this Sept. 30, 2011 file photo, Sailboats and a floating dock
lie on the dry, cracked dirt in a harbor at Lake Hefner in Oklahoma
City as drought continues to be a problem across the state.
The
research by a man often called the "godfather of global warming" says
that the likelihood of such temperatures occurring from the 1950s
through the 1980s was rarer than 1 in 300. Now, the odds are closer to 1
in 10, according to the study by NASA scientist James Hansen. He says
that statistically what's happening is not random or normal, but pure
and simple climate change.
"This is not some scientific theory. We are now experiencing scientific fact," Hansen told The Associated Press in an interview.
More Americans Accept Climate Change
Hansen is a scientist at NASA's Goddard Institute
for Space Studies in New York and a professor at Columbia University.
But he is also a strident activist who has called for government action
to curb greenhouse gases for years. While his study was published online
Saturday in the Proceedings of the National Academy of Science, it is
unlikely to sway opinion among the remaining climate change skeptics.
However, several climate scientists praised the new work.
In
a blunt departure from most climate research, Hansen's study - based on
statistics, not the more typical climate modeling - blames these three
heat waves purely on global warming:
-Last year's devastating Texas-Oklahoma drought.
-The 2010 heat waves in Russia and the Middle East, which led to thousands of deaths.
-The 2003 European heat wave blamed for tens of thousands of deaths, especially among the elderly in France.
The
analysis was written before the current drought and record-breaking
temperatures that have seared much of the United States this year. But
Hansen believes this too is another prime example of global warming at
its worst.
The new research makes the case for
the severity of global warming in a different way than most scientific
studies and uses simple math instead of relying on complex climate
models or an understanding of atmospheric physics. It also doesn't
bother with the usual caveats about individual weather events having
numerous causes.
The increase in the chance of
extreme heat, drought and heavy downpours in certain regions is so huge
that scientists should stop hemming and hawing, Hansen said. "This is
happening often enough, over a big enough area that people can see it
happening," he said.
Scientists have generally
responded that it's impossible to say whether single events are caused
by global warming, because of the influence of natural weather
variability.
However, that position has been
shifting in recent months, as other studies too have concluded climate
change is happening right before our eyes.
Hansen
hopes his new study will shift people's thinking about climate change
and goad governments into action. He wrote an op-ed piece that appeared
online Friday in the Washington Post.
"There is still time to act and avoid a worsening climate, but we are wasting precious time," he wrote.
The
science in Hansen's study is excellent "and reframes the question,"
said Andrew Weaver, a climate scientist at the University of Victoria in
British Columbia who was a member of the Nobel Prize-winning
international panel of climate scientists that issued a series of
reports on global warming.
"Rather than say,
`Is this because of climate change?' That's the wrong question. What you
can say is, `How likely is this to have occurred with the absence of
global warming?' It's so extraordinarily unlikely that it has to be due
to global warming," Weaver said.
For years
scientists have run complex computer models using combinations of
various factors to see how likely a weather event would happen without
global warming and with it. About 25 different aspects of climate change
have been formally attributed to man-made greenhouse gases in dozens of
formal studies. But these are generally broad and non-specific, such as
more heat waves in some regions and heavy rainfall in others.
Another
upcoming study by Kevin Trenberth, climate analysis chief at the
National Center for Atmospheric Research, links the 2010 Russian heat
wave to global warming by looking at the underlying weather that caused
the heat wave. He called Hansen's paper an important one that helps
communicate the problem.
But there is bound to
be continued disagreement. Previous studies had been unable to link the
two, and one by the National Oceanic and Atmospheric Administration
concluded that the Russian drought, which also led to devastating
wildfires, was not related to global warming.
White
House science adviser John Holdren praised the paper's findings in a
statement. But he also said it is true that scientists can't blame
single events on global warming: "This work, which finds that extremely
hot summers are over 10 times more common than they used to be,
reinforces many other lines of evidence showing that climate change is
occurring and that it is harmful."
Skeptical
scientist John Christy of the University of Alabama at Huntsville said
Hansen shouldn't have compared recent years to the 1950s-1980s time
period because he said that was a quiet time for extremes.
But
Derek Arndt, director of climate monitoring for the federal
government's National Climatic Data Center, said that range is a fair
one and often used because it is the "golden era" for good statistics.
Granger
Morgan, head of engineering and public policy at Carnegie Mellon
University, called Hansen's study "an important next step in what I
expect will be a growing set of statistically-based arguments."
In
a landmark 1988 study, Hansen predicted that if greenhouse gas
emissions continue, which they have, Washington, D.C., would have about
nine days each year of 95 degrees or warmer in the decade of the 2010s.
So far this year, with about four more weeks of summer, the city has had
23 days with 95 degrees or hotter temperatures.
Hansen says now he underestimated how bad things would get.
And
while he hopes this will spur action including a tax on the burning of
fossil fuels, which emit carbon dioxide, a key greenhouse gas, others
doubt it.
Science policy expert Roger Pielke
Jr. of the University of Colorado said Hansen clearly doesn't understand
social science, thinking a study like his could spur action. Just
because people understand a fact that doesn't mean people will act on
it, he said.
In an email, he wrote: "Hansen is
pursuing a deeply flawed model of policy change, one that will prove
ineffectual and with its most lasting consequence a further
politicization of climate science (if that is possible!)."
Website Link: http://www.weather.com/news/new-climate-change-study-20120805
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