By PAUL KRUGMAN
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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