By Robert A. Vella
As expected, President Trump pulled the U.S. out of the Paris Climate Accords yesterday. Also expected, an increasingly concerned world reacted with anger, dismay, and rhetorical self-interest. See:
At the same time, ominous climatic changes have been observed in Earth’s polar regions which support a new growing consensus that global warming is accelerating much faster than most scientists had expected.
Methane can form deep underground, where heat and pressure transform ancient organic material into methane gas. Fifteen thousand years ago during the Ice Age, when the Barents Sea was not yet a sea but an ice sheet, methane that migrated up through bedrock would have hit solid ice. It couldn’t go anywhere so it froze in place as methane hydrate. But as ice sheets melted to form a now liquid Barents Sea, the hydrates also began to turn back into methane gas. Pressure from this gas lifted the seafloor to create the giant mounds. With enough pressure, the mounds could blow, creating those giant craters.
Andreassen looked at the Barents Sea, but the same thing may have happened in other places when ice sheets retreated at the end of the Ice Age. Scientists have also found pingos in the Beaufort Sea north of Alaska and craters in the North Sea west of Norway.
And something similar may also be happening on land. In 2014, a number of huge craters appeared in Siberian. It was one of the hottest years on record in Siberia, and permafrost was melting. The craters were also found in areas rich in natural gas, and satellite imagery revealed mounds along with more craters. Russian scientists found clods of dirt that looked like they had been thrown from the craters. Irina Streletskaya, a geographer at Lomonosov Moscow State University who studied one of the craters, wrote in an email that she thinks trapped methane explains both the Barents Sea and Siberian craters.
New craters may be forming in the Barents Sea today, too. The smaller craters, says Andreassen, maybe the younger ones. But the bigger potential threat to climate change is not small methane blow-outs in the Barents Sea; it’s massive blow-outs that could happen in areas currently covered by ice. If ice sheets keep retreating in places like Greenland and Antarctica, it could leave more land bare and release long pent-up reservoirs of methane.
A massive crack in an Antarctic ice shelf grew by 11 miles in the past six days as one of the world’s biggest icebergs ever is poised to break off.
Only eight miles remain until the crack in the Larsen C ice shelf cuts all the way across, producing an iceberg about the size of the state of Delaware.
Adrian Luckman of Project MIDAS, a British Antarctic research project that’s keeping watch on the ever-growing crack, said it’s the largest jump since January. The full process is known as “calving,” the timing of which is “very close,” he added.
Once the iceberg breaks off, it “will fundamentally change the landscape of the Antarctic Peninsula,” he said.
Ice shelves are permanent floating sheets of ice that connect to a landmass, according to the National Snow and Ice Data Center. Since the ice is already floating, the newly created iceberg won’t contribute to rising sea levels.
Still, studying ice shelves and icebergs is important because they “hold back the glaciers that ‘feed’ them,” Luckman said. “When they disappear, ice can flow faster from the land to the ocean and contribute more quickly to sea-level rise.”