Is it climate change or just a string of bad natural luck?
Dissecting California’s drought
LAKE TAHOE, Calif. – What’s up with the weather? Yes, it has snowed in the last week but the big story during midwinter was “hot and dry’ in the Rockies. In California, now in the fourth year of drought, it was even worse, with hot weather from Mexico to Oregon over the Presidents’ Day Weekend.
A patch of abnormal weather or the front edge of a dramatically changing climate?
Climate scientists don’t agree, and those on the sidelines have argued even more vehemently.
“We’re now 15 percent of the way into the 21st century with runoff declines of 20 percent on the Colorado River,” says Brad Udall, senior water and climate research scientist/scholar at the Colorado Water Institute. “At what point can we say ‘this is climate change’ without being labeled some kind of kook?”
California continues to be pained. Heavenly, the Vail Resorts ski area that sits on the California-Nevada border had a little more than 40 percent of the ski area’s 4,800 acres open this weekend.
China Peak Mountain Resort had only the beginning skiing hill and a slope for sleds and inner-tubes open for Presidents’ Day weekend. “I’ve seen a couple wimpy years before, but nothing like this – nothing even close,” owner Tim Cohee told the Associated Press.
Storms have arrived, but with marginal good for ski areas. “When it’s raining at the top of the mountain, it’s awful hard to build a snowpack,” said Michael Anderson, the official state climatologist in California.
He told the AP that it was the second warmest January in recorded history but also the driest. The Sierra Nevada in January received 2 percent of its normal precipitation, with an average high temperature of 53 degrees.
Across the Rockies, it was more of the same: fog rarely, if ever, seen at mid-winter during the World Alpine Ski Championships at Vail/Beaver Creek. In Jackson Hole, the temperature one day hit 52 degrees during a time of year when above-freezing is rare. In Yellowstone National Park, grizzly bears were out and eating bison carcasses.
Meteorologists blame what they have taken to calling the “ridiculously resilient ridge” offshore the West Coast for both California’s woes of hot and dry and Boston’s recent cold and wet. But is this just ridiculous weather—or part of a shifting climate?
In December, the National Oceanic and Atmospheric Administration released a report by eight scientists that concluded that California’s drought was “due to natural variations of ocean systems, with sea surface temperatures largely responsible,” in the words of Richard Seager, the lead author. The new finding doesn’t refute the evidence that climate change is real, Seager told the San Jose Mercury News and other reporters. But in the case of the 2011-2014 California drought, natural variations were much more potent than human factors, the team concluded.
A different report from the American Geophysical Union found that the drought was unprecedented in the last 1,200 years. The authors, however, said that the drought was not outside the range of recent climate variability.
Taking stock of Colorado’s drenching rains in September 2013, NOAA so far has also refused to find a causal link to rising global temperatures—despite evidence that the global atmosphere now caries 3 to 5 percent more water vapor.
Other climate scientists found the new NOAA study wanting. Michael Mann, for example, pointed out that sea-surface patterns underlying the ongoing drought-favorable conditions may be partly forced, “and not simply a result of natural climate variability.” Nor, he added, did the NOAA study account for the potential influence of decreasing Artic Sea ice.
The study exposed a deep rift among climate scientists and others about the level of proof that should be required. “This isn’t about ‘causality’ but about ‘influence,’” said Peter Gleick, president of the Pacific Institute, an Oakland think tank that studies water policy. “The evidence is clear that human-induced climate change is influencing the drought, no matter the cause.”
Kevin Trenberth, a climate scientist with the National Center for Atmospheric Research, similarly argues that increased greenhouse gases add oomph to natural variability, giving Superstorm Sandy perhaps another 10 to 15 percent punch as it reached the Jersey shore and Manhattan.
Naomi Oreskes, a professor of the history of science at Harvard University, had a piece in the New York Times on Jan. 3 that accused climate scientists of being too timid. “It’s increasingly clear that they ought to be more emphatic about the risk,” she wrote. She says the scientific method that demands a 95 percent level of probability is too high. It means that science too often misses causes and effects that are really there.
In Aspen, a string of 50-plus temperature days plus the second driest January since records began in 1935 invited questions about the weather vs. climate change issue. The Aspen Global Change Institute has issued a report saying that skiing could end by 2100, but local meteorologist Cory Gates told The Aspen Times that it was the “most ridiculous statement on Earth.”
He said that the unusual weather of this winter is just that. “It just wasn’t our year in the West. Whoop-de-doo,” Gates said.
This originally appeared in the Feb. 25 issue of Mountain Town News. Obviously, the weather in the Southern Rockies took a turn after that.