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Don Paul: It’s a tangled web nature weaves in the Arctic

On Christmas Eve, a data buoy at the North Pole registered a temperature of 32 degrees Fahrenheit, which is about 50 degrees above average for this time of the year.

A massive low pressure storm system had pumped that warm air up to the top of the world. That general process of polar warming has happened many times in the past, though not to this record extent and not with the frequency such warmings have been occurring in recent decades.

Can this change be linked with climate change-induced global warming? The answer is: “very probably.”

Again, statistical correlation does not absolutely prove causation. Yet it must be noted information from many authoritative sources made public by Climate Central shows this kind of near freakish warming is now at a level of a 1-in-50 year event.

Friederike Otto, a climate scientist at Oxford University, states that a warming of this magnitude early in the 20th century would be statistically all but impossible. Climate models in the '80s and '90s correctly predicted the greatest amount of warming globally would occur in the Arctic, and that’s precisely what has occurred.

In November, North Pole temperatures ran an amazing 27 degrees above average. During this past year, Arctic ice cover was at its lowest peak coverage in March since satellite records began in 1979, and its second lowest minimum coverage in September. In fact, the November warmth was so extreme that ice coverage began thinning again (temporarily) at a time when thinning is unprecedented.

The Arctic is warming fastest because as ice melts and thins, its highly reflective surface shrinks, and the dark open waters can absorb more of the sun’s heat.

This creates a complex feedback mechanism.

With more exposed warmer sea water, more water vapor is released into the atmosphere over the high latitudes later in the summer and early autumn. This, in turn, allows more snow to fall many years in October over Siberia than used to be the case. As the sun lowers on the horizon, such a huge, advancing expanse of snow cover cools the atmosphere more rapidly and more extremely than used to be considered normal. The frigid air is of greater density, so that an enormous ridge of dense high pressure builds up over Siberia, altering the path of the polar jetstream which must move around this atmospheric mountain. In that transition, the polar jet often traverses the coldest latitudes and, if the polar vortex is sufficiently weak to allow the jet to buckle southward, that polar air can be delivered to some of the middle latitudes in the northern hemisphere.

The U.S. got a taste of this, especially in the northern plains, in December. There are early signs a colder – possibly much colder – pattern may be returning around mid-January.

So far, the coldest air in the northern hemisphere has been most persistent in Siberia and Mongolia. Nomadic tribespeople in Mongolia have been put at risk because their loss of livestock has increased due to the unusual severity of the cold, as well as the increased threat of frostbite and hypothermia among themselves.

With stable, frigid air in place, more people are burning coal and other fuels in desperate efforts to stay warm, and the strong temperature inversion (warmer air aloft over the cold air at the surface) in such a stagnant arctic air mass traps the pollutants near the surface creating some of the most dangerous air pollution in recent decades near the Mongolian capital.

There is a scientific irony in all this. Well, it’s not really ironic to atmospheric scientists, but it can seem counterintuitive to the casual reader.

The fact that climate change-induced warming has led to increased frequency of abnormal snowfall on the vast Siberian basin in October which, in turn, leads to more severe cold outbreaks in parts (not all) of the northern hemisphere during the early and mid-winter may read as irony.

Yet this warming quite apparently can be directly related to harsher winter weather at times in the middle latitudes of eastern North America, western Europe and large expanses of central and northern Asia. None of these harsh winter outbreaks can counter the overall global warming which is ongoing, in case you’re wondering. The number of record high temperatures during the course of a year compared to record lows is no longer even roughly balanced.

Arctic ice continues to shrink and doesn’t thicken as much as it used to prior to this warming (the total mass of Antarctic ice is lessening as well, but the Antarctic is a vast continent, unlike the Arctic, and regional dynamics differ compared to the Arctic Ocean).

This feedback mechanism is also leading to melting of the permafrost in the high latitudes of Eurasia and North America. During the warm season, this melting allows the release of more methane, a potent greenhouse gas (it traps 23 times more heat than CO2, but it doesn’t persist in the atmosphere as long). This trend in the Arctic has little spikes and valleys, but the median is clear.

There may be a few positives in all this, come the opening of a Northwest Passage for cruise ships and freighters (and naval warships) during warm months.

What’s obvious, however, is that the negatives in these trends will continue to far outweigh the positives.

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