Positive feedbacks are driving climate change

How Feedback Loops Are Driving Runaway Climate Change

Dahr Jamail

Truth-Out,

1 October, 2018

If you think this summer has been intense as far as record warm temperatures, wildfires, drought, and flooding events around the Northern Hemisphere, you haven’t seen anything yet — unless you happen to live in the Arctic.

According to the US National Oceanic and Atmospheric Administration (NOAA), air temperatures there are increasing at an “unprecedented rate” — twice as fast as they are around the rest of the globe. NOAA’s 2017 Arctic Report Card states unequivocally that the Arctic “shows no sign of returning to reliably frozen region of recent past decades.”

The Executive Summary of the report also adds, “Arctic paleo-reconstructions, which extend back millions of years, indicate that the magnitude and pace of the 21st century sea-ice decline and surface ocean warming is unprecedented in at least the last 1,500 years and likely much longer.”

A recent report from National Geographic revealed that some of the ground in the Arctic is no longer freezing, even during the winter. Along with causing other problems, this will become yet another feedback loop in the Arctic, causing yet more greenhouse gasses to be released from permafrost than are already being released and impacting the entire planet.

The simplest explanation for a positive climate feedback loop is this: The more something happens, the more it happens. One of the most well-known examples is the melting of sea ice in the Arctic during the summer, which is accelerating. As greater amounts of Arctic summer sea ice melt away, less sunlight is reflected back into space. Hence, more light is absorbed into the ocean, which warms it and causes more ice to melt, and on and on.

Dr. Ira Leifer is an academic researcher who specializes in bubble-related oceanographic processes (such as subsea bubble plumes emanating from the ocean floor), satellite remote sensing, and air pollution. Working closely with NASA on some of his projects, Leifer uses the agency’s satellite data to study methane in the Arctic and its role in climate disruption.

One of his concerns about a feedback loop already at play in the Arctic is how the heating of that region is already being amplified by ocean currents that transport warmer, more southerly waters northwards into Arctic seabed waters where it can affect methane deposits in submerged permafrost and sub-seabed methane hydrates.

“The release of this methane contributes powerfully to overall warming – methane is a very potent greenhouse gas, which actually has a bigger effect [on] the atmosphere’s radiative balance than carbon dioxide on decadal timescales,” Dr. Leifer told Truthout.

Dr. Peter Wadhams is a world-renowned expert who has been studying Arctic sea ice for decades.

His prognosis for the Arctic sea ice is grim: He says it is in its “death spiral.”

“Multi-year ice is now much less than 10 percent of the area of the ice cover; it was 60 percent or more before 2000,” Dr. Wadhams told Truthout. “[Sea ice] extent in summer is down to 50 percent of its value in the 1980s.”

Dr. Wadhams, who is also the President of the International Association for the Physical Sciences of the Ocean (IAPSO), noted that this primary feedback loop is much further along than most of us realize.

“I see the summer sea ice disappearing by the early 2020s,” Wadhams said. He noted that the change of albedo (a measure of reflection of solar radiation) due to the loss of sea ice and snowline retreat across the Arctic “is sufficient to add 50 percent to the warming effect of CO2 emissions alone.”

Alarmingly, on August 21, Arctic scientists told The Guardian that the oldest and strongest sea ice in the Arctic had broken up for the first time in recorded history. One of them described the event as “scary,” in part because it occurred off the north coast of Greenland, which is normally frozen year-round. The region has long been believed to be “the last ice area”: It was thought, at least until now, to be the final place that would hold out against the melting impacts from an increasingly warmer planet.

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