Tough Sledding….

28 12 2016

Happy Holidays all,

markcochrane2

Mark Cochrane

Last weekend I was treated to a morning of trying to drive my daughter to her swim meet in -32 degree (-50 wind chill) temperatures (Fahrenheit and Celsius are about the same at these temperatures). Annually this sort of thing, or a big snowstorm somewhere leads to either denial of global climate change or the ‘an ice age is coming’ drivel.

However, every time we have massive unseasonable cold somewhere, spare a thought for what that actually means. That cold air didn’t just spring into existence, it had to come from somewhere. If the lower latitudes are experiencing this influx of cold air that means that something has to be back filling the air in the north. Translation, it gets very warm up north in the northern hemisphere. Remember, the key word in global climate change is ‘global’.

This year, yet again, the North Pole is experiencing a massive Christmas heat wave, raising temperatures to near freezing (32 F or 0 C, take your pick). Now this could be just ‘natural variability’ but each year that it keeps happening weakens that argument. You can’t have 1000-yr events every year or two again and again and call that ‘natural’. For several years now I have been a proponent of the theory that this is a signal of ongoing global climate change (e.g.Cohen et al. 2013). Debate is still ongoing in the scientific community about what is driving this phenomenon but it makes too much sense to me that it is linked to the dropping ice coverage in the Arctic ocean for it to be all chalked up to ‘natural variability’, which is just a weasel term for shit that happens periodically that we can’t convincingly explain.

The Arctic is showing stunning winter warmth, and these scientists think they know why

Last month, temperatures in the high Arctic spiked dramatically, some 36 degrees Fahrenheit above normal — a move that corresponded with record low levels of Arctic sea ice during a time of year when this ice is supposed to be expanding during the freezing polar night.

And now this week, as you can see above, we’re seeing another huge burst of Arctic warmth. A buoy close to the North Pole just reported temperatures close to the freezing point of 32 degrees Fahrenheit (0 Celsius), which is 10s of degrees warmer than normal for this time of year. Although it isn’t clear yet, we could now be in for another period when sea ice either pauses its spread across the Arctic ocean, or reverses course entirely.

But these bursts of Arctic warmth don’t stand alone — last month, extremely warm North Pole temperatures corresponded with extremely cold temperatures over Siberia. This week, meanwhile, there are large bursts of un-seasonally cold air over Alaska and Siberia once again.

It is all looking rather consistent with an outlook that has been dubbed “Warm Arctic, Cold Continents” — a notion that remains scientifically contentious but, if accurate, is deeply consequential for how climate change could unfold in the Northern Hemisphere winter.

So once again, Santa might be facing some tough sledding this year…

Merry Christmas,

Mark

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