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Climate: Greenhouse gas buildup ‘loads the dice’ for Southwest megadroughts

Odds of 30-year dry spells increase dramatically as global temps rise

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Green bars indicate wet periods, the larger the bar the more unusually wet. In a similar way, yellow indicates dry and droughty periods. The graph stretches from January 1895 on the left to last month on the right, showing how the cycle of droughts alternating with wet years has changed, with dry years becoming more prevalent.

By Summit Voice

FRISCO — Tree ring records clearly show that the southwestern U.S. experienced megadroughts long before the anthropogenic global warming era. One such decades-long dry spell may have been a factor in the collapse of the Anasazi civilization at Mesa Verde.

But the steady buildup of heat-trapping gases in the atmosphere is loading the dice in favor of another megadrought sooner, rather later, according to scientists with Cornell University, the University of Arizona and U.S. Geological Survey. The chances of a decade-long drought is now at least 50 percent, and there’s a 20 percent to 50 percent chance of a 30-year megadrought.

“For the southwestern U.S., I’m not optimistic about avoiding real megadroughts,” said Toby Ault, Cornell assistant professor of earth and atmospheric sciences and lead author of the paper. “As we add greenhouse gases into the atmosphere – and we haven’t put the brakes on stopping this – we are weighting the dice for megadrought conditions.” Continue reading

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Global warming spells trouble for fish populations in desert rivers of the Southwest

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Dwindling precipitation in the Southwest spells trouble for native fish. bberwyn photo.

Study shows significant loss of fish habitat by mid-century

Staff Report

FRISCO — Big sections of vulnerable stream habitat for native fish in the Southwest are likely to disappear by mid-century as global warming causes stream flows to dwindle.

By 2050, stream-drying events could increase by 17 percent, and the number of zero-flow days could go up by 27 percent in the Verde River Basin, affecting species like speckled dace (Rhinichthys osculus), roundtail chub (Gila robusta) and Sonora sucker (Catostomus insignis).

The drying trend will fragment aquatic habitat, hampering feeding and spawning. Some populations that are already isolated may very well disappear, said Ohio State University researcher Kristin Jaeger, an assistant professor at the School of Environment and Natural Resources. Continue reading

Study tracks early Native American ‘baby boom’

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Mesa Verde was a center of southwestern civilization. Photo courtesy National Park Service.

Native American population history may offer lesson for modern society, as climate change may have caused subsequent crash

Staff Report

FRISCO — Everybody knows about the post-WWII baby boom, but there was another era when North America’s population swelled, as Native Americans in the Southwest shifted from hunting and gathering to agriculture.

The “growth blip” between about 500 and 1300 A.D. is probably linked with emerging early features of civilization — including farming and food storage — and birth rates may have “exceeded the highest in the world today,” according to research published in the journal Proceedings of the National Academy of Sciences.

But like so often in human history, the boom was followed by a crash, offering a warning sign to modern societies about the potential risks of overpopulation, according to Tim Kohler, an anthropologist at Washington State University, who co-authored the paper with WSU researcher Kelsey Reese. Continue reading

Climate: New study projects major habitat losses for birds, reptiles in Southwest

Gray jay in Summit County Colorado

A gray jay searches for bugs in a stand of lodgepole pines near Frisco, Colorado.

A few bird species may gain some ground

By Summit Voice

FRISCO — Reptile species like the iconic chuckwalla will probably experience significant habitat loss as global temperatures climb during the next few decades, scientists said this week in a new study projecting climate change impacts to southwestern birds and reptiles.

The study was done by scientists with the U.S. Geological Survey,  University of New Mexico, and Northern Arizona University. Overall, the findings suggests many reptile species will lose ground as conditions get warmer and more dry.  Continue reading

Biodiversity: Feds finalize critical habitat for jaguars

Jaguar. Image via the Wikimedia Commons.

Jaguar. Image via the Wikimedia Commons.

Nearly 1,200 square miles of territory protected for recovery of native cats

By Summit Voice

FRISCO — Nearly 17 years after federal biologists first listed jaguars under the Endangered Species Act, the wild cats may now have a protected area to roam in the wilds of the Southwest.

The U.S. Fish and Wildlife Service this week designated about 1,200 square miles of rugged desert, mountain and forest lands in southern Arizona and New Mexico as critical habitat for jaguars — but only after a sustained legal push by the Center for Biological Diversity.

The federal wildlife agency initially resisted mapping out protected areas, claiming that the cats are too rare for habitat protection. Wildlife advocates challenged the agency’s position and a federal court rejected the government’s argument, leading to this week’s critical habitat listing notice in the Federal Register. The USFWS is also working on a jaguar recovery plan for the area. Continue reading

Water: How long will the Southwest’s acequias survive?

Dartmouth study details threats to historic communal irrigation 

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A patchwork of fields around Taos, New Mexico

Staff Report

FRISCO — The historic communal irrigation systems known as acequias Southwest are in decline as snowmelt dwindles and water priorities shift. Social and economic shifts favoring modernism over tradition, are also factors on the decline, according to a new study from Dartmouth College.

Similar trends have been observed in other parts of the world, where rural communities that once fended for themselves are becoming integrated into larger economies, which provide benefits of modern living but also the uncertainties of larger-scale market fluctuations. The study appears in the journal Global Environmental Change. Continue reading

Climate: Is the Southwest ‘stuck’ in a drought pattern?

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NOAA’s winter outlook offers little relief for Arizona, New Mexico

By Bob Berwyn

FRISCO — Drought conditions may persist across the southwestern U.S. this winter and may redevelop across the Southeast, according to the seasonal outlook from NOAA’s Climate Prediction Center.

“Even though we don’t have La Niña, the atmosphere across the Pacific seems to be stuck in a La Niña mode … It’s been quite surprising to us, how persistent the pattern is,” said Mike Halpert, acting director of the Climate Prediction Center.

Parts of the Southwest, especially New Mexico, have been experiencing one of the driest periods on record, and Halpert said there is “decent agreement” in the CPC’s models on the climate signal that has resulted in the persistent trend. Continue reading

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