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Climate: Wet West in July

Energetic monsoon brings moisture surplus to many areas

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The big wet?

By Summit Voice

FRISCO — An energetic and widespread monsoon weather pattern brought above normal precipitation to much of the West in August, with a bullseye of moisture in southern Idaho, extending across western Wyoming, Montana, northeastern Utah and into northwestern Colorado. Some locations in the region saw up to 800 percent of average precipitation. Continue reading

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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

Climate: U.S. average temp cooler than average in July

Hot and cold pattern persists

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The yin and yang of climate, with hot readings in the far West and below-average temperatures the Midwest, along the Atlantic seaboard and the deep south. Map courtesy NCDC.

Summit Voice

FRISCO — A hot-and-cold pattern continued over the continental U.S. in July, with some western states reporting record and near-record warmth, while parts of the Midwest were record cold for the month. Continue reading

Climate: Greenhouse gases drive Australia drying trend

Since the 1970s, southern Australia has been experiencing declining rainfall in the fall and winter, creating scenes like this one in a 2007 photograph at Lake Hume. (Creative Commons/ Suburbanbloke)

Since the 1970s, southern Australia has been experiencing declining rainfall in the fall and winter, creating scenes like this one in a 2007 photograph at Lake Hume. (Creative Commons/ Suburbanbloke).

New model can resolve some climate impacts on a regional scale

STAFF REPORT

FRISCO — Increasing concentrations of greenhouse gases and ozone depletion over Antarctica are the main drivers of the long-term decline in rainfall over southwestern Australia, federal scientists said in a weekend press release.

The findings, published in Nature Geoscience, are derived from a new  high-resolution climate model that may help researchers identify more links between heat-trapping gases and regional climate trends, including here in the U.S. Continue reading

Climate: Utah tree-ring study shows severity of historic megadroughts

Luminosity.

Old Douglas firs can help reveal historic climate cycles.

Recent dry spells not so bad compared to past centuries

Staff Report

FRISCO — A tree-ring reconstruction of Utah’s climate going back to 1429 shows that the state has experienced several mega-droughts in past centuries that would be life-changing if they happen again, according to Brigham Young University professor Matthew Bekker.

The worst drought of the modern era, the 1930s Dust Bowl, barely ranks on the top 10 list of droughts in that 500-year span,” Bekker said. The findings reinforce similar studies for the Colorado River Basin. Continue reading

Western wildfires burning bigger and more often

Global warming seen as key factor in trend

wildfire acreage graph

Study documents significant trend in size and frequency of western wildfires.

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Western wildfires: How much bigger will they get?

By Summit Voice

FRISCO — The size and frequency of western wildfires have been increasing at a startling rate the past few decades, researchers said this week after scrutinizing satellite data to measure burned areas.

The number of wildfires larger than 1,000 acres increased by a rate of seven fires a year from 1984 to 2011 and the total areas burned grew by about 90,000 acres per year — an area the size of Las Vegas, according to the new study accepted for publication in Geophysical Research Letters, a journal published by the American Geophysical Union.

“We looked at the probability that increases of this magnitude could be random, and in each case it was less than one percent,” said Philip Dennison, an associate professor of geography at the University of Utah in Salt Lake City and lead author of the paper. Continue reading

Environment: Is the Amazon rainforest near a tipping point?

A NASA photo taken from the International Space Station shows sunlight glinting off the Amazon River.

A NASA photo taken from the International Space Station shows sunlight glinting off the Amazon River.

Drought the main driver of destructive fires

By Staff Report

FRISCO — Longer droughts, land-use changes and wildfires may  be pushing parts of the Amazon rainforest toward an ecological tipping point, a team of scientists said after analyzing the effects of fire in a series of study plots.

The changes may abruptly increase tree mortality and change vegetation over large areas, the researchers said, pointing out that current Amazon forest models don’t include the impacts of wildfires. As a result, projections of future forest health tend to underestimate the amount of tree death and overestimate overall forest health, said Dr. Michael Coe, of the Woods Hole Research Center. Continue reading

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