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Arctic Communities And Permafrost Thaw | Earth Wise

December 16, 2021 By EarthWise Leave a Comment

Permafrost is frozen soil, rock or sediment that can be as much as a few thousand feet thick. To qualify as permafrost , the material has to have been at or below the freezing point of water for two or more years. Most of it is located in high latitudes in the Arctic and Antarctic regions. Permafrost covers nearly a quarter of the exposed land in the Northern Hemisphere.

Permafrost contains enormous amounts of carbon in the form of frozen soil that includes remnants of plants and animals, in some cases that have been there for more than 20,000 years.

The Arctic region has been warming faster than any place else on earth and thawing permafrost is already unleashing methane and carbon dioxide to the atmosphere, adding to the global temperature rise.

Apart from the impact on the global climate, thawing permafrost is making the ground unstable and is causing serious problems for local communities.

Recent research using satellite observations provides an overview of the Arctic to identify communities and infrastructure that will be at risk over the next 30 years.

Using high-resolution data from the Copernicus Sentinel satellite missions along with ground-based data going back to 1997, researchers modeled the permafrost ground temperature trends and extrapolated them out to 2050. The results were that 55% of the infrastructure currently located on permafrost and within 60 miles of the Arctic coastline – infrastructure on which many communities rely – is likely to be affected.

Most human activity in the Arctic takes place along permafrost coasts. Permafrost thaw is exposing these coasts to rapid change that threatens biodiversity and puts pressure on communities.

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Satellites pinpoint communities at risk of permafrost thaw

Photo, posted January 24, 2014, courtesy of Brandt Meixell / USGS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildfires And Giant Sequoias

October 28, 2021 By EarthWise Leave a Comment

Two massive California wildfires that erupted during a lightning storm on September 9 have continued to threaten groves of giant sequoia trees in the southern Sierra Nevada mountains. As of the beginning of October, flames from the KNP Complex fire had burned in or passed through 11 sequoia groves, including the famed Giant Forest in Sequoia National Park.

Hundreds of firefighters battled to protect some of the most renowned trees, including the 275-foot-tall General Sherman tree, widely considered to be the largest tree on earth by overall volume. That tree and many near it are over 2,000 years old.

Firefighters wrapped the base of the General Sherman and several other trees with fire-resistant blankets to protect them from the intense heat of approaching fires. Sequoias are actually well-adapted to fires because of their thick bark that protects them from heat. But intense fires like the KNP Complex and Windy fires are more than the trees can handle.

As of the beginning of October, both fires continue to blaze, but thanks to the efforts of firefighters, most of the giant sequoias have survived. One massive tree in the Giant Forest recently toppled over after burning for several days, but most are still standing and haven’t suffered serious damage.

As of early October, the two fires had blackened over 140,000 acres across national parks, national forests, the Tule River Indian Reservation, and local communities. These two are among multiple wildfires burning in California this past summer. The largest – the Dixie fire – has burned nearly a million acres as of early October. In total, over 2.5 million acres have already burned in California this year.

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KNP Complex fire triggers flurry of new evacuations, as flames threaten more giant sequoia trees

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Hundreds of California firefighters battle to protect ancient sequoia groves from raging wildfires – with world’s largest tree General Sherman wrapped in aluminum foil blanket

Photo, posted November 5, 2017, courtesy of Ken Lund via Flickr.

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More Antarctic Warming

April 23, 2019 By EarthWise Leave a Comment

East Antarctica is the coldest place on Earth. It makes up two-thirds of the continent, is home to the South Pole, and has vast ice sheets that have been around for tens of millions of years and are nearly three miles thick in places. Temperatures there hover around 67 degrees below zero. In 2010, a few spots on East Antarctica’s polar plateau reached a record-breaking 144 degrees below zero.

But almost unbelievably, parts of the East Antarctic seem to be melting.

Scientists are seeing worrying signs of ice loss in the East Antarctic. Glaciers are starting to move more quickly and are dumping their ice into the Southern Ocean. Satellite images show the fast-moving ice. The biggest glacier – the Totten Glacier – alone contains enough ice to raise global sea levels by over 12 feet.

The Antarctic as a whole contains about 90% of the planet’s ice. In theory, if it all melted, it would raise global sea levels by an average of 200 feet.

The growing concerns about eastern Antarctica are not that its interior plateau will soon start to melt. It is still extremely cold there and should stay that way for a long time. But its edges, which are in contact with warming ocean waters, are the real worry. As the region’s ice shelves, which float atop the Southern Ocean, erode, the vast glaciers behind them could rapidly accelerate their slide into the sea.

Today, satellites show huge glaciers moving rapidly toward the coast, with wide rivers of ice sometimes moving several miles a year. In the face of rapid change and limited data, it is difficult to predict what the Antarctic will do in the future. But it doesn’t look good.

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Polar Warning: Even Antarctica’s Coldest Region Is Starting to Melt

Photo, posted January 3, 2013, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.