Will global warming desiccate the Southwest?

‘A normal year in the Southwest is now drier than it once was’

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Will the Southwest’s life-giving rains fade away? @bberwyn photo.

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A federal climate assessment projects soaring temperatures for the Southwest.

Staff Report

A subtle long-term shift in atmospheric patterns driven by global warming could lead to longer and more intense droughts in the southwestern U.S. and other semi-arid regions. Most climate models suggest that that a belt of higher average pressure that now sits closer to the equator will move north. This high-pressure belt is created as air that rises over the equator moves poleward and then descends back toward the surface.

That shift may already be affecting the climate of the Southwest, as moisture-bearing weather patterns have become more rare in the region, according to a new study. Previous research has suggested that the region’s forests and fish and birds are in big trouble. In Australia, researchers are nearly certain that global warming was a factor in a record-breaking 2013 heatwave. A federal climate assessment released in 2013 also identified similar concerns for the Southwest.

“A normal year in the Southwest is now drier than it once was,” said Andreas Prein, a postdoctoral researcher at the National Center for Atmospheric Research who led the study. “If you have a drought nowadays, it will be more severe because our base state is drier.” Continue reading

Can the Southwest’s forests survive global warming?

New study projects widespread forest mortality by 2100

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Vast swaths of spruce trees have died in southern Colorado during the past few years. Photo courtesy U.S. Forest Service.

Forest ecosystems around the world are under the gun from climate change, development, insect invasions and conversion to agriculture. This stand of lodgepoles in Colorado was clear cut after pine beetles killed most of the trees.

Forest ecosystems around the world are under the gun from climate change, development, insect invasions and conversion to agriculture. This stand of lodgepoles in Colorado was clear cut after pine beetles killed most of the trees. @bberwyn photo.

Staff Report

Unless deep greenhouse gas cuts happen soon, last month’s historic climate agreement may be too little, too late for some forests in the American Southwest, where scientists are projecting a widespread die-off of needleleaf evergreens — including pine, spruce, piñon and juniper trees — by 2100.

After combining data from field observations with climate model projections, the research team concluded that  72 percent of the region’s needleleaf evergreen forests will die by 2050, with nearly 100 percent mortality by 2100.

“No matter how we investigated the problem, we got the same result. This consensus gives us confidence in this projection of forest mortality,” said Sara Rauscher, assistant professor of geography in University of Delaware’s College of Earth, Ocean, and Environment.

It’s pretty clear that the die-off is already under way. Even drought-resistant species like piñon pines were hit hard by a drought in the early 2000s. A massive bark beetle infestation wiped out millions of acres of lodgepole pines in the southern Rockies, and spruce beetles have taken a big toll on once-lush spruce forests in southern Colorado. Continue reading

Critical fire weather forecast across big swath of Southwest

All of Arizona, New Mexico encompassed in weekend warning from National Weather Service

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The National Weather Service is highlighting a large part of the Southwest for critical fire weather conditions. Hot temperatures and winds are expected.

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The Whitewater-Baldy Fire burning in New Mexico in June 2012. Photo courtesy Kari Greer/USFS.

Staff Report

FRISCO — In what may signify an early start to the western wildfire season, the National Weather Service Sunday issued bulletin warning that multiple days of critical fire weather conditions are expected across the Southwest this coming week.

From the NWS website:

“A dry airmass will be in place from the Great Basin to the Plains on Sunday. Temperatures warming into the 60s and 70s with wind gusts near 35 mph and relative humidity values from 10 to 15 percent will lead to elevated to critical fire danger. These conditions will likely remain in place until mid-week. Rapid growth and spread is likely with any fires that are ignited in and around this region.”

The warning for this week is a shift away from a seasonal forecast issued last month that didn’t include any elevated early season fire danger in the region. Parts of the Southwest saw some relief from a multi-year drought this winter, but overall, the region is still dry and fire danger can be significant even during normal precipitation years.

The areas with the highest potential for dangerous fires extends from southeastern California through southern Nevada, southeastern Utah, far western Colorado and covers nearly all of Arizona and much of New Mexico.

Both New Mexico and Arizona saw their largest wildfires on record during the past several years, including the 2011 Wallow Fire in Arizona, which burned across half a million acres (about 841 square miles). In New Mexico, the 2011 Las Conchas Fire burned about 150,000 acres, following by the Whitewater-Baldy Complex Fire in 2012 in Catron County, New Mexico, which scorched nearly 300,000 acres.

 

 

 

 

Climate study projects brutal Western droughts

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Shrunken reservoirs may become the norm across the West during the second half of the century. bberwyn photo.

All models point to significant drying and warming

Staff Report

FRISCO — By the second half of this century, the relentless increase in global greenhouse gases could push the U.S. Southwest and Great Plains toward persistent drought conditions worse than anything seen in ancient or modern times.

Drought conditions will likely be more severe than during several decades-long megadroughts that are well-documented by paleoclimate records, according to climate scientists with the Lamont-Doherty Earth Observatory at Columbia University’s Earth Institute.

Continue reading

Energy: New Southwest power line to boost production, distribution of renewable energy

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Energy infrastructure improvements are key to tapping renewable resources.

‘The SunZia transmission line will finally unlock New Mexico’s stranded wind and solar resources and move that energy to market’

Staff Report

FRISCO — A $2 billion, 550-mile transmission line project will bolster the U.S. energy grid’s capacity to use power generated from renewable sources in the Southwest, Obama administration leaders said as they announced approval for the SunZia Southwest Transmission Project.

The line will run from the proposed SunZia East Substation in Lincoln County, New Mexico, to the existing Pinal Central Substation in Pinal County, Arizona.

“The SunZia Project will help unlock the abundant renewable energy resources in the Southwest, creating jobs and bringing reliable, sustainable power to a growing corner of our country,” said Interior Secretary Sally Jewell. Continue reading

Climate: Extended droughts spell trouble for Southwest birds

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Some birds won’t nest at all during drought years.

Some Sonoran Desert species skip breeding entirely during extreme drought

Staff Report

FRISCO — Drought-driven delayed nesting by some southwestern bird species may lead to crashing populations, scientists said in a new study that looked closely at Sonoran Desert bird species, such as Black-tailed Gnatcatchers and Verdins.

The research suggests drought conditions are delaying nesting by two weeks or more for some species. Despite recent rainfall, drought conditions persist in much of the Southwest, making life tough even for species adapted to a dry environment.

Delayed nesting makes the birds more vulnerable to nest predators and parasites, according to the scientists with Point Blue Conservation Science and the U.S. Geological Survey finds that increased drought frequency in southwestern North America results in increased instances of delayed nesting. Continue reading

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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