(another refugee from that black hole at email@example.com)
The short headline reads, “Drought’s Link to Climate Change Is Disputed” (New York Times, Justin Gillis). The evidence cited, however, is a version of “We’ve seen this before,” which might be an appropriate response had someone said “unprecedented” but which does not help establish doubt about a role of climate change. This misleads. Why should the standard be the discovery of brand-new phenomena, when all climate change has to do is to alter where and when the usual suspects return to the stage?
Another staple of climate coverage is when a cause is implied to be this-or-that. In reality, causes are always plural. No sooner do you learn about gravity causing the fall of Newton’s apple than you are faced with gravity being insufficient to explain the speed of the fall. Air resistance is also acting on the apple.
If everything has multiple causes, why do climate scientists go along with how reporters frame “the cause” question? The appropriate answer is nearly always, “Drought has a mix of causes. Climate change is not a new one. It just alters the mix.”
There is, however, a reason that overheating will create more drought episodes, and in new places. It comes, not from the global average overheating (which obscures uneven overheating), but because there are hot-spots, called continents.
We know that land has been warming twice as fast as the ocean surface. The Arctic warmed even faster. Unless warm air stops rising, we have to expect a rearrangement of our usual winds and moisture delivery. What would be surprising is if drought patterns did not change. That’s the appropriate starting point for discussing drought prospects.
And as long as overheating keeps increasing, there will never be a settled new arrangement of winds and moisture delivery. The obvious conclusion is that climate instability is going to characterize the future.
Averages often obscure important drivers. Rain arriving at inconvenient times can, for example, flatten grain crops in midsummer, leaving them to rot. Deluge and drought may come as a pair, yet not show up in the annual averages which continue to frame our approach to the climate problem.
Extreme weather can strike a serious blow to our civilization, and do so much more quickly than the effects of the slow rise in local temperature. In this new era of climate instability, don’t make the mistake of thinking things will change gradually. Or predictably.
All bets are off, which is bad news for our just-in-time food supply line. It’s time to return to the pharaoh’s policy of keeping a seven year stockpile of grain.
William H. Calvin is a professor emeritus at the University of Washington’s medical school in Seattle.