Re: “Global Warming? Not Always,” by Martin P. Hoerling (Sunday Review, March 9, 2014):
As California’s severe drought has worsened, there has been persistent debate about the links between drought and climate change (or indeed any extreme weather event). Three key, but very different, questions are often confused: Has climate change caused the current drought? Is it already influencing or affecting the drought (no matter its cause)? And how will climate change affect future droughts?
But this is the wrong question to ask. The current drought has certainly been exacerbated by climate change for one simple reason: Temperatures in California are now higher today, as they are globally. This alone increases water demand by crops and ecosystems, accelerates snowpack loss, and worsens evaporation from reservoirs. There are other complicating effects, but the influence of higher temperatures on drought is already real and cannot be ignored.
We are now unambiguously altering the climate, threatening water supplies for human and natural systems. This is but one example of how even today we are paying the cost of unavoidable climate changes.
PETER GLEICK, JONATHAN OVERPECK, CONNIE WOODHOUSE
Oakland, Calif., March 10, 2014
Dr. Gleick is president of the Pacific Institute. Dr. Overpeck is a professor of geosciences and atmospheric sciences and Dr. Woodhouse is a professor of geography and geosciences at the University of Arizona, Tucson.
Farmers continue to grow alfalfa, rice and other thirsty crops. Their resource use has been heavily subsidized by the government. According to The Economist, they have paid a paltry 15% of the capital costs of the federal system that delivers much of the water to their fields. Thus, farmers have no incentive to irrigate their farmlands efficiently.
After a few more weeks of the rainy season, much of California will bake, increasing the likelihood of wildfires. The water table has decreased in many areas, prompting farmers to drill deeper to reach groundwater, further depleting aquifers.
In January, Gov. Jerry Brown issued a drought declaration and urged Californians to cut water use by 20%. About $183 million in federal aid that has been pledged, coupled with $687 million in California aid, should bring some relief.
Los Altos, Calif., March 9, 2014
Monmouth Beach, N.J., March 9, 2014
As California endures a historic drought, many are wondering why Gov. Jerry Brown supports expanding a practice that severely jeopardizes our water: hydraulic fracturing, or fracking.
San Francisco, March 9, 2014
The writer is an anti-fracking organizer for the Center for Biological Diversity.