From Water Deeply (Tom Philip):
If we are adequately to talk about the weather this century, we are going to need a new lexicon that better captures the current reality, writes Tom Philp of Metropolitan Water District.
Water policy is becoming a prisoner of its own limited vocabulary, particularly when it comes to the weather. Here is a case that “drought” and “normal” belong in the dustbin of history, for their overuse can lead to the wrong conversation. These words are not so sinister as to be banned from the dictionary. But they tend to miss the mark as to what seems to be happening with our weather this century.
First, the case against “drought.”
In California, a drought only happens when a governor declares it to be so. It is invariably announced via an executive order when the state is already well into a publicized dry pattern. Likewise, Sacramento declares the drought over after it has been raining like mad.
Yes, dry years strung together are important. They have their acute set of management problems. The recent multi-year dryness brought true hardship to many communities, farmers and aquatic ecosystems throughout the state. Longer streaks may lie ahead.
But looking back at California’s weather so far this century, we have been “dry” (as in below-average precipitation) two years out of three. Sometimes they have come in streaks that draw temporary attention. Sometimes they have been sandwiched in between by a single wet year.
Being dry two years out of three is a very big deal. For lack of a better term, it is like a Semi Drought. A Dry Period. This needs a name. This has some very serious consequences.
There is evidence throughout the West that groundwater basins have suffered because of this chronic semi-drought. The University of Arizona recently documented the emerging problems of the Semi Drought.
And Southern California, even with intensive groundwater management, has not been immune from the impacts. Based on information collected by the Metropolitan Water District of Southern California, local groundwater production has decreased by more than 200,000 acre-feet since 2000. The net loss is roughly equivalent to the annual residential needs of the cities of San Diego, Burbank, Anaheim, Long Beach, Glendale and Garden Grove.
No governor has ever declared California to be in a chronic Semi-Drought. Perhaps this weather trend is rarely discussed, and never declared, because we haven’t settled on a catchy word that describes what has steadily emerged to be our most challenging long-term weather problem.
Second, the case against “normal.”
Yes, normalcy has an unavoidable mathematical purpose. There must be a benchmark for a past to describe the present. But there really is not such a thing as normal, or average, in the state that has had the most variable weather in the country. And the experts seem to be telling us that things will be even less “normal” in the future.
Cases in point are two studies that came out of the Scripps Institution of Oceanography at the University of California-San Diego last fall. They pointed to even more volatility, as in dramatic swings from wet to dry years (sound familiar?) in the future.
“Rainfall in a warmer future will be delivered in less frequent but more intense events,” Scripps meteorologist Alexander Gershunov said at the time.
As Gershunov intimated, the Scripps research also pointed to more frequent dry years in the future. That is more evidence that the Semi Drought that is under way is truly the norm.
Meanwhile, we all watch the weather. We all wonder what about the future. And we converse about it in yesteryear’s language.
If we truly are in a long and challenging Semi-Drought, or whatever we end up calling it, whether it is very wet or very dry or very “average” in any given year is important in the short term. But in the long term, it is a statistical asterisk.