The National Oceanic and Atmospheric Administration delivered an Arctic Report Card earlier this month on the effects of climate change in the high latitudes. None of the news in the report is good.
I’ve written a number of articles concerning the rapid warming in the arctic latitudes, which was well-predicted even in earliest climate models. ( Here is one such article, from last May.)
The basic feedback mechanism is as follows: Warming accelerates sea ice melt in the summer, leading to increased open waters absorbing more solar energy due to their dark coloring replacing the highly reflective white surfaces of ice. That leads to warming oceans, increased evaporation and thinner ice upon refreezing, causing more rapid melting linked to more thin ice in the late spring and summer. And so on. That is the very essence of feedback; it is not entirely linear, but the trend is irrefutable.
Back to the report card.
Starting with air temperatures this past year, NOAA states: “The average annual land surface air temperature north of 60° N for October 2018-August 2019 was the second warmest since 1900. The warming air temperatures are driving changes in the Arctic environment that affect ecosystems and communities on a regional and global scale.”
Pardon the cliché, but that’s not even the half of it. All signs point to the arctic region’s drawing closer to becoming a net carbon emitter. A great deal of that is due to melting permafrost, not only in Alaska, but also over a huge portion of Siberia that froze during the last ice age 12,000 years ago without the glacial cover that reached so much of Europe and North America. This vast tract of permafrost has even larger stores of carbon and methane from more abundant frozen plant and animal life, now being released as melting progresses.
NOAA estimates the sum of arctic carbon emission to range from 300 billion to 600 billion tons of net new carbon into the atmosphere annually. This means these hundreds of billions of tons are emissions that weren’t a major factor just a few decades ago. From that, we get the global effects of additional warming tied to the emissions and the ocean heating, as well as the increasing rate of sea level rise from melting glaciers and the Greenland ice cap combined with volume expansion of water due to heating. As has been accurately reported by Washington Post science editor Andrew Freedman, based on published data I have seen: “There has been concern throughout the scientific community that the approximately 1,460 billion to 1,600 billion metric tons of organic carbon stored in frozen Arctic soils, almost twice the amount of greenhouse gases as what is contained in the atmosphere, could be released as the permafrost melts.”
Once this melting gets underway, bacteria in the soil hasten the conversion of trapped carbon into its greenhouse gaseous state. Chemists and physicists have weighed these additional and growing emissions with the amount that can be taken up by global vegetation, and there is no semblance of a balance.
The oceans still absorb vast sums of carbon and heat, but that produces its own negative feedback, which, in addition to sea level rise, is directly linked to coral reefs’ death, decimation of some fish populations and northward migration of other fish, damaging fish harvests and restoration efforts in some fishing grounds.
NOAA manages the nation’s fisheries and ocean waters, and their report illustrates problems for the many indigenous tribes who depend on coastal settlements for subsistence. While there has been a net increase in some fish populations from the northward migration, a growing number of villages are being abandoned due to land sinking caused by the melting and the consequent storm surge damage from powerful arctic low-pressure systems. Some arctic land wildlife populations are declining in a number of species due to the warming, and the ever-present mosquito populations in the tundra have been exploding as more tidal pools and open areas of water result from the melting.
The arctic area of greatest sea ice concern in the last two years has been the Bering Sea, where ice cover reduction and warming have leapfrogged ahead of the rest of the arctic, with severe consequences on fishing and crabbing, along with economic consequences on native populations.
In the end, the arctic emissions are the byproduct of midlatitude human activity leading to more emissions-linked warming. Therein lies the hastened pace of the feedback mechanisms. Warming begets more warming.
However, real uncertainty remains about the future volume of arctic and ocean-bed-melting permafrost-related emissions. Most climate scientists still believe that with some drastic reductions in fossil fuel burning and changes in agricultural technology in the next decade, the worst-case global scenarios for late in the century can be mitigated. New technological breakthroughs in energy storage are already beginning to improve the outlook for alternative energy technologies in the role of producing more power for our economies.
In the meantime, leading climate and atmospheric scientist Michael Mann of Penn State recently had somewhat more hopeful words in October for a Sydney newspaper. (Ironically, Australia has just undergone its hottest week on record this past week, with more heat to come.)
“The greatest threat I see to climate action is the paralysis that comes from disengagement, disillusionment, despair,” he told the Sydney Morning Herald and the Age on a flying visit from the United States this week. “It would be one thing if we were really doomed. … As a scientist, it would be disingenuous of me to argue otherwise. But the science tells us we can still make the reductions in carbon emissions necessary to avert the worst impacts of climate change.
“Yes, there is urgency, but we still have agency.”
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