Category: climate and weather

Will global warming boost groundwater supplies in the Upper Colorado River Basin?

Some climate models project more rainfall in the West

A bend in the Yampa River near Dinosaur National Monument in northwest Colorado.
Will global warming boost flows in Colorado River tributaries? @bberwyn photo.

Staff Report

While most recent research suggests that the Colorado River will be depleted well beyond current demands as global temperatures increase, there may be one small bright spot on the horizon. Even if runoff from snow declines, groundwater replenishment in the basin may hold stead under projected increases in  precipitation, the U.S. Geological Survey and U.S. Bureau of Reclamation found in a new study.

“You can’t manage what you don’t measure,” said Fred Tillman, lead author and USGS scientist. “These results are the first step in understanding the quantity of groundwater we can expect in the Upper Colorado River Basin; however, further studies are needed to help more accurately forecast future groundwater availability.”

The Colorado River is a critically important source of water for more than 35 million people in the United States and 3 million people in Mexico. As much as half the water flowing in the rivers and streams in the Upper Colorado River Basin originates as groundwater. Understanding how much groundwater is available and how it’s replenished is important to sustainably manage both groundwater and surface water supplies in the Colorado River basin now and in the future.

In the new study, USGS and Reclamation scientists estimated projected changes in groundwater recharge for the Upper Colorado River Basin from recent historical (1950–2015) through future (2016–2099) time periods using climate projections and a groundwater-recharge model.

Simulated future groundwater recharge through 2099 is generally expected to be somewhat greater than the historical average in most decades due to an anticipated wetter future climate in the basin under the most advanced climate modeling projections. Groundwater resources are replenished through increases in precipitation, which may offset reductions from increased temperatures. The full report is available online in the journal Geophysical Research Letters.

But researchers urged caution interpreting the results because a few of the models suggested  decreased future recharge relative to the historical climate period.

Continue reading “Will global warming boost groundwater supplies in the Upper Colorado River Basin?”

What’s the tipping point for Antarctica’s ice sheets?

New study suggests rapid meltdown during post-ice age warming

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How long will it take for Antarctica’s ice sheets to melt? @bberwyn photo.

Staff Report

After taking a close look at rocks from West Antarctica’s dramatic Ellsworth Mountains, climate researchers say there’s a chance that ice sheets in the region could melt quickly as the planet warms, potentially causing sea level to rise by  six to eight feet.

The new study, published in Nature Communications, took a close look at Antarctic climate change about 21,000 years ago during a period of warming after the coldest point of the most recent Ice Age. They found that  the West Antarctic Ice Sheet reached a tipping point, after which it thinned relatively quickly, losing 400m of thickness in 3,000 years. Continue reading “What’s the tipping point for Antarctica’s ice sheets?”

Climate: July breaks global temperature mark — again

Mideast heatwave set records

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All northern hemisphere land areas recorded above average temperatures in July 2016.

Staff Report

There was no letup to the global heatwave in July, according to the National Oceanic and Atmospheric Administration, which reported this week that the month ended up as the warmest ever recorded on planet Earth.

Federal climate trackers said it was the 15th month in a row with above average temps, making it the longest such streak in NOAA’s 137 years of record keeping. The global temperature for July has been above average for 40 years in a row, since 1976. July was also the 379th consecutive month with temperatures above the 20th century average. The last month with temperatures below the 20th century average was December 1984, at 0.09 degrees Celsius below average.

The combined average temperature over global land and ocean surfaces was 0.87 degrees Celsius above the 20th century average, besting the previous July record set in 2015 by 0.06 degrees Celsius. Across the world’s land areas, the average temperature was 1.10 degrees Celsius above the 20th century average. Continue reading “Climate: July breaks global temperature mark — again”

Harley-Davidson to pay $15 million for cheating on clean air rules

Et tu, Harley-Davidson?

Court settlement includes mitigation and buy-back program

Staff Report

Volkswagen isn’t the only company to try and circumvent clean air rules. This week, Harley-Davidson agreed to pay a $12 million civil penalty for installing illegal devices that increase air pollution from their motorcycles.

Under the court-approved settlement, the company also agreed to spend $3 million to mitigate air pollution by replacing older wood stoves with cleaner heating units, and to  stop selling and to buy back and destroy the so-called super-tuners.

According to court documents, Harley-Davidson manufactured and sold about 340,000 of the devices, that, once installed, caused motorcycles to emit higher amounts of certain air pollutants than what the company certified to EPA. Aftermarket defeat devices like these super tuners alter a motor vehicle’s emissions controls and are prohibited under the Clean Air Act for use on vehicles that have been certified to meet EPA emissions standards. Continue reading “Harley-Davidson to pay $15 million for cheating on clean air rules”

Study says current rate of sea level rise is unprecedented in recent history

‘Our study is for sea level what the now well-confirmed famous ‘hockey stick’ diagram was for global temperature’

As global warming drives rising sea levels and more intense storms, some communities are looking to augment their beaches with "imported" sand. like here on Manasota Key in Englewood, Florida.
As global warming drives rising sea levels and more intense storms, some communities are looking to augment their beaches with “imported” sand, like here on Manasota Key in Englewood, Florida. @bberwyn photo.

Staff Report

The global rise of sea level may not be as dramatic or as easily visible as some other signs of global warming like melting glaciers, but it will be one of the most destructive and expensive long-term impacts. With a huge percentage of the world’s population living in coastal regions, society will need to take costly measures to protect people. In some cases, there will no option but to move entire communities away from the rising waters.

While there is still some uncertainty among climate scientists as to the extent of future sea level rise, there is little doubt that the current increase is unprecedented in recent times, according to a recent study by scientists with the Potsdam Institute for Climate Impact Research.

“Our study  is for sea level what the now well-confirmed famous ‘hockey stick’ diagram was for global temperature,” said Stefan Rahmstorf, co-author of the paper on past sea-level rise and Co-Chair of PIK’s research domain Earth System Analysis. “We can confirm what earlier, more local sea-level data already suggested: during the past millennia sea-level has never risen nearly as fast as during the last century.”

The researchers said greenhouse gas emissions have caused at least half of the observed sea level rise in the 20th century, and possibly even all of it.

While the study didn’t break new ground in terms of projections, it’s important to be able to show with great certainty how much sea level will rise, Rahmstorf said.

“The new sea-level data confirm once again just how unusual the age of modern global warming due to our greenhouse gas emissions is – and they demonstrate that one of the most dangerous impacts of global warming, rising seas, is well underway.”

Barring any catastrophic climate feedback loops that could accelerate the meltdown of Arctic and Antarctic ice, the researchers said sea-levels worldwide will rise by 50 to 130 centimeters by the end of this century if greenhouse gas emissions are not reduced rapidly.

“With all the greenhouse-gases we already emitted, we cannot stop the seas from rising altogether, but we can substantially limit the rate of the rise by ending the use of fossil fuels,” said PIK’s Anders Levermann, who specializes in climate adaptation.

“We try to give coastal planners what they need for adaptation planning, be it building dikes, designing insurance schemes for floodings, or mapping long-term settlement retreat.”

Even if the world’s countries live up to the 2015 Paris climate agreement, sea level will rise 20 to 60 centimeters by 2100.

“This is quite a challenge, but less expensive than adaptation to unabated sea-level rise which in some regions is impossible”, Levermann adds. “If the world wants to avoid the greatest losses and damages, it now has to rapidly follow the path laid out by the UN climate summit in Paris.”

The likely future sea-level rise cannot be brought down to just one number, but is represented as a range, which at first sight might seem large.

“The range allows for a risk assessment,” said Ben Marzeion from the University of Bremen, Germany. “Coastal Planners need to know how a reasonable worst-case scenario as well as a well-founded best-case scenario look like to weigh chances and costs. The best available science is now converging towards a common uncertainty range of future sea-level rise. Curbing greenhouse gas emissions now gives us the chance to prevent sea level rise to accelerate further.”

Why is the government spying on climate activists?

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Fossil fuel protestors targeted by undercover investigations

Staff Report

The threat of international terrorism apparently is not keeping federal agents so busy that they don’t have time to investigate the largely peaceful community of climate activists who are advocating for a rapid shift to a carbon-free energy economy.

In recent months, federal and local law enforcement agencies have cooperated with fossil fuel companies to spy on groups like 350.org and the Break Free movement, as shown by a series of documents obtained by The Intercept. Those records show that agents went underground to monitor the groups activities and training sessions. Of course, such domestic intelligence operations aren’t new — paranoid government agencies have a long history of tracking activists going back at least to Dr. Martin Luther King. Continue reading “Why is the government spying on climate activists?”

Climate: Arctic sea ice melt slows slightly in July

Experts say record low now unlikely

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Summer sea ice off the east coast of Greenland. @bberwyn photo.

Staff Report

Cool and stormy weather in the Arctic during July slowed the rate of sea ice loss to just below average for the month,  making it less likely sea ice extent will dwindle to a record low, according to the latest update from the National Ice and Snow Data Center. But it all depends on conditions the next few months.

For the month, sea ice extent averaged 2.14 million square miles, the third-lowest for July since satellite records started in 1979. It was only the second month of 2016 that didn’t end with a record-low extent, according to the NSIDC. The sea ice extent in July was 73,000 square miles above the previous record low 637,000 square miles below the 1981 to 2010 long-term average. Through 2016, the rate of decline for the month of July is 28,070 square miles per year, about 7.3 percent per decade. Continue reading “Climate: Arctic sea ice melt slows slightly in July”