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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

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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

Climate: Warmer temps to drive spread of drought

State officials hope to be well-prepared for the next inevitable drought in Colorado.

Drought is expected to expand the southwestern U.S. and other regions.

Evaporation seen as huge factor in climate calculations

Staff Report

FRISCO — Increasing global temperatures will drive drought expansion regardless of precipitation in some cases, as more moisture evaporates from soils.

An increase in evaporative drying means that even regions expected to get more rain, including important wheat, corn and rice belts in the western United States and southeastern China, will be at risk of drought. The study excludes Antarctica.

The new study models the effects of both changing rainfall and evaporation rates on future drought, estimating that 12 percent of land will be subject to drought by 2100 through rainfall changes alone; but the drying will spread to 30 percent of land if higher evaporation rates from the added energy and humidity in the atmosphere is considered.

Continue reading

Climate: Scientists study link between tropical belt expansion and multi-decadal oceanic circulation patterns

Long-term Pacific Ocean cycles could be driving SW drought

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What’s the role of natural climate variability in Southwestern droughts?

Staff Report

FRISCO — If you’re ready to blame drought in the southwestern U.S. on global warming, it might be time to rethink that conclusion.

According to scientists with the University of California, Riverside, dry conditions in the region may be linked with an expansion of the Earth’s tropical belt during the past few decades. And that expansion is likely driven by multi-decadal sea surface temperature variability in the Pacific Ocean, according to the new study. Other explanations for this widening have been proposed, including radiative forcing due to greenhouse gas increase and stratospheric ozone depletion. Continue reading

Western streamflow forecasts a mixed bag

Severe drought continues in Southwest

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California, Arizona and New Mexico reporting very dry conditions.

By Summit VoiceFRISCO — Snowpack across the West is still somewhat of mixed bag in this no-Niño winter, but February storms did help bolster water supplies across the northern tier of states, according to the monthly update from USDA’s Natural Resources Conservation Service.

East of the Continental Divide as well as parts of Washington, northern Oregon, northern Idaho and western Montana are now forecast to have near-normal or above normal water supplies, according to the forecast from the NRCS National Water and Climate Center. Continue reading

Climate: February 2014 cooler than average in U.S.

Dry conditions persist in far West

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February 2014 emperatures varied widely across the country.

Staff Report

FRISCO — The average February temperature across contiguous United States was well below the 20th century average. With an average reading of 32.2 degrees Fahrenheit (1.6 degrees below average), last month will go down in the books at the 37th-coldest February on record, the National Climatic Data Center reported in its regular monthly update.

The winter season overall (December to February) was 1.0 degrees Fahrenheit below average, making it the coldest winter since 2009-2010. This winter stood in sharp contrast to the last two winters, and most winters of the past two decades, when temperatures were predominately warmer than the 20th century average, the climate data center said. Read the full report here. Continue reading

Climate: USGS says most California streams flowing at less than 10 percent of normal

Widespread western drought continues

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Much of the West has been very dry during the first four months of the 2014 water year.

By Summit Voice

As California experiences its worst drought in more than a century, it’s probably not surprising that some stream gages in the northern part of the state are showing all-time record low readings, with 2013 in the record books as the driest calendar year in the state’s 119-year recorded history.

Low streamflow affects water availability for agricultural, municipal, and industrial uses, water quality, water temperature, recreational opportunities, and the maintenance of fish populations.

Recent precipitation has resulted in some increases in streamflow, snowpack, and reservoir levels, but severe drought conditions remain. Without significant additional precipitation, prior conditions will quickly return leaving most streams in the state at less than 10 percent of normal for this time of year. Continue reading

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