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Global warming: More extreme rainfall events nearly certain

Warmer atmosphere, more moisture, more rain

Breckenridge, Colorado recently recorded an all-time 24-hour record rainfall event during a summer thunderstorm. Bob Berwyn photo.

Breckenridge, Colorado recently recorded an all-time 24-hour record rainfall event during a summer thunderstorm. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — Large parts of the northern hemisphere could see a 20 to 30 percent increase in extreme precipitation events by the end of the century. Extra moisture due to a warmer atmosphere dominates all other factors, leading to notable increases in the most intense precipitation rates, according to a new NOAA-led study.

The study shows a 20-30 percent expected increase in the maximum precipitation possible over large portions of the Northern Hemisphere by the end of the 21st century if greenhouse gases continue to rise at a high emissions rate.

“We have high confidence that the most extreme rainfalls will become even more intense, as it is virtually certain that the atmosphere will provide more water to fuel these events,” said Kenneth Kunkel, Ph.D., senior research professor at the Cooperative Institute for Climate and Satellites-North Carolina and lead author of the paper. Continue reading

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What’s the climate tipping point for permafrost?

Cave study offers clues on temperature threshold

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Global permafrost is a significant factor in the climate-change equation. Map courtesy United Nations Environmental Program.

By Summit Voice

SUMMIT COUNTY — Climate scientists have long been warning that a meltdown of Arctic permafrost will trigger a spike in greenhouse gas emissions as long-frozen organic soils give up their carbon to the atmosphere. What’s not yet clear is how fast and how much of the permafrost will melt, but a new study helps identify a temperature threshold that could lead to widespread melting.

A team led by Oxford University scientists studied stalactites and stalagmites in caves along Siberia’s permafrost frontier, where the ground begins to be permanently frozen in a layer tens to hundreds of meters thick.

The stalactites and stalagmites only grow when liquid rainwater and snow melt drips into the caves. The formations record 500,000 years of changing permafrost conditions, including warmer climate periods. After studying the paleoclimate clues in the caves, the researchers concluded that another 1.5 degrees of warming would be enough to cause substantial thawing of permafrost far north from its present-day southern limit. Continue reading

Draft report IDs key global warming threats

Activists say deep greenhouse gas cuts needed to avoid climate disaster

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Seasonal temperature anomalies by season in 2012.

By Summit Voice

FRISCO — A recent federal draft report on climate change has spurred renewed calls for deep cuts in greenhouse gas emissions to avert the most serious impacts from rising global temperatures.

The report, which is in a public comment phase, concludes that global warming is already affecting the U.S. Warmer temperatures will endanger food supplies, increase the risk of flooding and powerful hurricanes, and warm the country by as much as 10 degrees by 2100.

The report finds that global warming has already delivered hotter summers, more flooding and periods of extreme heat that “last longer than any living American has ever experienced.” Continue reading

Global warming: The longer we wait, the harder it gets

Meeting 2-degree warming target requires immediate action

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Even without El Niño, Nov. 2012 temps were far above average across most of the globe. Graphic courtesy NASA.

By Summit Voice

SUMMIT COUNTY — Delaying meaningful action on climate change is tempting, but will likely prove to be very costly in the long run, an international group of researchers warned this week in an article in Nature Climate Change.

The easiest path is to reaching the targeted 2-degree cap in global temperatire increases would be to significantly cut greenhouse gas emissions. If that doesn’t happen by 2020, the goal is still attainable, but at a much greater cost, with much higher climate risks and and under exceedingly optimistic assumptions about future technologies.

Timely cuts in emissions leaves more doors open in the long run, said the researchers from the International Institute for Applied Systems Analysis in Laxenburg, Austria, ETH Zurich in Switzerland, and the National Center for Atmospheric Research in Boulder.

The researchers say this is what needs to happen sooner, rather than later:

Nuclear power would need to remain on the table as a mitigation option, or people would need to quickly adopt advanced technology strategies, including electric vehicles and highly efficient energy end-use technologies such as appliances, buildings, and transportation. Meanwhile, coal-fired power plants would need to be rapidly shut down and replaced with other energy sources.

“You would need to shut down a coal power plant each week for ten years if you still wanted to reach the two-degree Celsius target,” said IIASA energy program leader Keywan Riahi, who also worked on the study. Continue reading

Global warming: Sea level going up, up up …

The Greenland ice sheet is thinning, according to NASA data. Click on the image for more information.

Ice sheet melting may be slow, but it’s inexorable

By Summit Voice

SUMMIT COUNTY — Study after study has been done on how global warming will affect sea level, and it appears that, no matter how you slice and dice it, coastal areas will see significant impacts during the coming centuries.

In one of the latest research projects, scientists tried to factor in all of the Earth’s ice, including some 200,000 glaciers worldwide, concluding that a sea-level rise of 1.1 (about 3.5 feet) meters by the year 3000 is inevitable. Continue reading

Traveling in a warming world

Global warming accepted as fact in Austria; mountain communities planning for year-round tourism

Storm clouds build over Salzburg, Austria.

Many of Austria’s alpine glaciers are melting quickly, leading to concerns about long-term water supplies. Photo courtesy The Canary Project. Please click on the photo for more information.

By Bob Berwyn

SUMMIT COUNTY — Leaving Colorado in the midst of one of the most brutal heatwaves and droughts on record, it was hard to not think about global warming and climate change, especially after driving past thousands of acres of withered and stunted corn around DIA, with smoke from wildfires near and far hanging over the Front Range.

We were hoping our family visit to Austria would offer some relief, and sure enough, temperatures stayed in the 70s and low 80s during much of the time, a far cry from our last couple of trips to area, including 2003, when much of Europe was gripped by extreme warmth that killed up to 15,000 people in France. Continue reading

Global warming: American Meteorological Society says there’s no room for doubt on climate change

‘Prudence dictates extreme care’

Global July temperatures were the fourth-warmest on record. Graphic courtesy NASA.

By Summit Voice

SUMMIT COUNTY — While there are still a few prominent TV weather announcers who publicly question the overwhelming body of global warming science, the American Meteorological Society has updated its official position on climate change, acknowledging unequivocally “that Earth’s lower atmosphere, ocean, and land surface are warming; sea level is rising; and snow cover, mountain glaciers, and Arctic sea ice are shrinking. The dominant cause of the warming since the 1950s is human activities.”

“This statement is the result of hundreds of hours of work by many AMS members over the past year,” said AMS executive director Keith Seitter. “It was a careful and thorough process with many stages of review, and one that included the opportunity for input from any AMS member before the draft was finalized,” Seitter said. The full statement is online at the AMS website.

After describing in detail what’s known about climate change, the AMS statement ends with a poignant warning: “Prudence dictates extreme care in accounting for our relationship with the only planet known to be capable of sustaining human life.” Continue reading

Climate change: scientists ponder cloud brightening

Geoengineering idea floated as a way to slow global warming

Could brightening clouds help slow the march of global warming? Photo courtesy NOAA.

By Summit Voice

SUMMIT COUNTY — With international efforts to limit heat-trapping greenhouse gases faltering, some scientists say it’s worth at least exploring the concept of creating clouds that might reflect sunlight to counter global warming.

Geoengineering has always had a few proponents, as there are always some people who think that we can engineer our way out of any problem. But many of the ideas floated as possible solutions to global warming are just vague theories at best, with little evidence that they could work.

Now, University of Washington atmospheric physicist Rob Wood describes a possible way to run an experiment to test the concept of cloud brightening on a small scale. His idea is described in a paper published this month in the journal Philosophical Transactions of the Royal Society.

Wood makes it clear he’s not advocating for geoengineering, but wants to encourage more scientists to consider the idea of marine cloud brightening and even poke holes in it. Continue reading

Global warming: Reservoir drawdowns a factor in atmospheric methane levels

Reservoir drawdowns appear to have the potential to increase heat-trapping methane in the atmosphere.

Study measures increased methane emissions as reservoir levels drop

By Summit Voice

Lowering water levels in reservoirs may significantly increase emissions of heat-trapping methane gas, according to Washington State University researchers who measured dissolved gases in the water column of Lacamas Lake.

Graduate student Bridget Deemer found methane emissions jumped 20-fold when the water level was drawn down. A fellow WSU-Vancouver student, Maria Glavin, sampled bubbles rising from the lake mud and measured a 36-fold increase in methane during a drawdown.

Methane is 25 times more effective than carbon dioxide at trapping heat in the atmosphere. And while dams and the water behind them cover only a small portion of the earth’s surface, they harbor biological activity that can produce large amounts of greenhouse gases. There are also some 80,000 dams in the United States alone, according to the U.S. Army Corps of Engineers National Inventory of Dams.

“Reservoirs have typically been looked at as a green energy source,” Deemer said. “But their role in greenhouse gas emissions has been overlooked.” Continue reading

Colorado: Coal still king in Summit County energy mix

The Four Corners coal power plant. Photo courtesy EcoFlight.org. Click to track Ecoflight state by state.

70 percent of the power for the local area derived from dirty fossil fuels

By Summit Voice

SUMMIT COUNTY — Despite small-scale hyperlocal efforts to cut greenhouse gas emissions, the local area still relies on coal to a much larger degree than the national average, according to an online EPA clean energy tracker.

The calculations, based on data from 2009, show that, for Frisco’s 80443 zip code, coal accounts for 67.8 percent of the energy used in the area. The national average is 44.5 percent. Continue reading

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