Paul Krugman: Loading the Climate Dice

The costs of climate change are already here:

Loading the Climate Dice, by Paul Krugman, Commentary, NY Times: 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... 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 ... 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. ...

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..., suggested the analogy of loaded dice. Imagine ... 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,... 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..., 9 of the 10 hottest years on record have occurred since 2000. But that’s not all: really extreme high temperatures ... have now become fairly common. Think of it as rolling two sixes, which happens ... more often when the dice are loaded. And this rising incidence of extreme events ... means that the costs of climate change aren’t a distant prospect, decades in the future. On the contrary, they’re already here...

The great Midwestern drought is a case in point. This drought has already sent corn prices to their highest level ever..., it could cause a global food crisis... 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. ... Will the current drought finally lead to serious climate action? History isn’t encouraging. The deniers will surely keep on denying... 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.