Posted on August 27, 2014 by Bob Berwyn
Odds of 30-year dry spells increase dramatically as global temps rise
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
Filed under: climate and weather, Drought, extreme weather, global warming | Tagged: Arizona, California drought, climate change, global warming, greenhouse gases, megadrought, New Mexico, Southwest | Leave a comment »
Posted on August 18, 2014 by Bob Berwyn
‘In our data we find unambiguous evidence of anthropogenic contribution to glacier mass loss’
Shrinking glaciers on the Dachstein Mountains in Austria will affect water supplies far downstream in local areas and in distant rivers. bberwyn photo.
FRISCO — Some of the world’s glaciers were shrinking before the onset of unchecked heat-trapping pollution, but the human factor in the glacial equation has grown exponentially in the past few decades.
A new modeling study led by scientists at the University of Innsbruck (Austria) shows that only about 25 percent of the global glacier mass loss during the period of 1851 to 2010 is attributable to anthropogenic causes. However, between 1991 and 2010 the fraction increased to about two-thirds.
“In the 19th and first half of 20th century we observed that glacier mass loss attributable to human activity is hardly noticeable but since then has steadily increased,” said researcher Ben Marzeion, explaining that scaled-down regional models can detect an anthropogenic influence in America and the Alps, where glacier changes are particularly well documented. Continue reading
Filed under: climate and weather, Environment | Tagged: climate, Environment, glaciers, global warming, greenhouse gases, mountains, water | Leave a comment »
Posted on July 30, 2014 by Bob Berwyn
Cutting methane could slow global temperature surge.
Action could help avert climate tipping points
FRISCO — Leading scientists say the U.S. must do more to cut methane emissions from fossil fuel exploitation and other sectors to try and avoid reaching climate tipping points that could have disastrous implications.
Methane is a much more potent heat-trapping gas than carbon dioxide, but it only stays in the atmosphere for about 12 years, which means that big cuts could have a tangible short-term benefit in the race to cap global warming. Continue reading
Filed under: climate and weather, energy, Environment, global warming, greenhouse gases | Tagged: climate change, Environment, global warming, greenhouse gases, methane | Leave a comment »
Posted on May 22, 2014 by Bob Berwyn
The Four Corners Power Plant in a 1972 photo via Wikipedia.
Satellite data verified by in-stack measurements
By Summit Voice
FRISCO — Keeping tabs colorless, odorless carbon dioxide emissions is not always easy, yet it will be crucial someday for being able to measure whether countries are meeting targets for emissions reductions.
Scientists with Los Alamos National Laboratory now say they’ve been able to measure air pollution and greenhouse gases from the two coal-fired power plants in the Four Corners — the largest single point source of pollution in the U.S. Continue reading
Filed under: climate and weather, Environment | Tagged: air pollution, Four Corners Power Plant, global warming, greenhouse gases, Los Alamos National Laboratory | Leave a comment »
Posted on May 6, 2014 by Bob Berwyn
A computer-generated split-screen image a split-image simulates the average 20 percent best (left) and 20 percent worst 20 percent (right) visibility at the Long’s Peak vista based on an average of monitored data for years 2000-2004.
Very likely without cuts in pollutants, study says
FRISCO — By 2050, many Americans will see their chances of experiencing unhealthy summertime ozone levels increase by 70 percent, according to scientists with the National Center for Atmospheric Research. Warmer temperatures will make the toxic brew of air pollutants even more volatile unless emissions of specific pollutants that are associated with the formation of ozone are sharply cut, the researchers said in a new study published this week.
Almost all of the continental United States will experience at least a few days with unhealthy air during the summers, the research shows. Heavily polluted locations in parts of the East, Midwest, and West Coast where ozone already frequently exceeds recommended levels could face unhealthy air during most of the summer. Continue reading
Filed under: air quality, climate and weather, Environment, global warming, greenhouse gases | Tagged: climate change impacts, global warming, greenhouse gases, ozone pollution, smog | 1 Comment »