Loading the Climate Dice

By PAUL KRUGMAN

The New York Times

July 22, 2012

http://www.nytimes.com/2012/07/23/opinion/krugman-loading-the-climate-dice.html?_r=1&wpisrc=nl_wonk

A couple of weeks ago the Northeast was in the grip of
a severe heat wave. As I write this, however, it's a
fairly cool day in New Jersey, considering that it's
late July. Weather is like that; it fluctuates.

And this banal observation may be what dooms us to
climate catastrophe, in two ways. On one side, the
variability of temperatures from day to day and year to
year makes it easy to miss, ignore or obscure the
longer-term upward trend. On the other, even a fairly
modest rise in average temperatures translates into a
much higher frequency of extreme events -- like the
devastating drought now gripping America's heartland --
that do vast damage.

On the first point: Even with the best will in the
world, it would be hard for most people to stay focused
on the big picture in the face of short-run
fluctuations. When the mercury is high and the crops
are withering, everyone talks about it, and some make
the connection to global warming. But let the days grow
a bit cooler and the rains fall, and inevitably
people's attention turns to other matters.

Making things much worse, of course, is the role of
players who don't have the best will in the world.
Climate change denial is a major industry, lavishly
financed by Exxon, the Koch brothers and others with a
financial stake in the continued burning of fossil
fuels. And exploiting variability is one of the key
tricks of that industry's trade. Applications range
from the Fox News perennial -- "It's cold outside! Al
Gore was wrong!" -- to the constant claims that we're
experiencing global cooling, not warming, because it's
not as hot right now as it was a few years back.

How should we think about the relationship between
climate change and day-to-day experience? Almost a
quarter of a century ago James Hansen, the NASA
scientist who did more than anyone to put climate
change on the agenda, suggested the analogy of loaded
dice. Imagine, he and his associates suggested,
representing the probabilities of a hot, average or
cold summer by historical standards as a die with two
faces painted red, two white and two blue. By the early
21st century, they predicted, it would be as if four of
the faces were red, one white and one blue. Hot summers
would become much more frequent, but there would still
be cold summers now and then.

And so it has proved. As documented in a new paper by
Dr. Hansen and others, cold summers by historical
standards still happen, but rarely, while hot summers
have in fact become roughly twice as prevalent. And 9
of the 10 hottest years on record have occurred since
2000.

But that's not all: really extreme high temperatures,
the kind of thing that used to happen very rarely in
the past, have now become fairly common. Think of it as
rolling two sixes, which happens less than 3 percent of
the time with fair dice, but more often when the dice
are loaded. And this rising incidence of extreme
events, reflecting the same variability of weather that
can obscure the reality of climate change, means that
the costs of climate change aren't a distant prospect,
decades in the future. On the contrary, they're already
here, even though so far global temperatures are only
about 1 degree Fahrenheit above their historical norms,
a small fraction of their eventual rise if we don't
act.

The great Midwestern drought is a case in point. This
drought has already sent corn prices to their highest
level ever. If it continues, it could cause a global
food crisis, because the U.S. heartland is still the
world's breadbasket. And yes, the drought is linked to
climate change: such events have happened before, but
they're much more likely now than they used to be.

Now, maybe this drought will break in time to avoid the
worst. But there will be more events like this. Joseph
Romm, the influential climate blogger, has coined the
term "Dust-Bowlification" for the prospect of extended
periods of extreme drought in formerly productive
agricultural areas. He has been arguing for some time
that this phenomenon, with its disastrous effects on
food security, is likely to be the leading edge of
damage from climate change, taking place over the next
few decades; the drowning of Florida by rising sea
levels and all that will come later.

And here it comes.

Will the current drought finally lead to serious
climate action? History isn't encouraging. The deniers
will surely keep on denying, especially because
conceding at this point that the science they've
trashed was right all along would be to admit their own
culpability for the looming disaster. And the public is
all too likely to lose interest again the next time the
die comes up white or blue.

But let's hope that this time is different. For
large-scale damage from climate change is no longer a
disaster waiting to happen. It's happening now.

___________________________________________

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