Is Arctic sea ice now in death spiral?

Arctic sea ice

One of the most tangible and visual representations of a major climatic system undergoing change as a result of a warming planet is the melting of the Arctic ice cap.

For a number of reasons, well-understood by climatologists, the higher northern latitudes have been subject to the most extreme warming. Whilst global average temperatures are now a smidgen over 1 degree warmer than pre-industrial levels (66% or 50% of the way to the agreed limit from Paris), warming in the Arctic is between 5 and 6 degrees warmer.

Arctic sea ice ebbs and flows massively between the seasons, expanding and contracting rapidly, with a peak generally in early March and the trough in September. In winter, there is around 2.5 times more ice cover than summer.

But since satellite records began monitoring daily sea ice extent in 1979, the long term trend for winter, but particularly summer ice extend is down. And rapidly.

Original estimates from the IPCC’s First Assessment report predicted total loss of summer ice by around the end of the 21st century. Recently scientists have begun to speculate the first ice-free summer might be  – wait for it – this coming northern hemisphere summer. Either way, the earlier models have underestimated the actual rate of decay.

Alarmist? Possibly, but the catastrophic summer of 2012, which absolutely smashed the previous low record of 2007, by approximately 18% and the 2016 record low winter maximum, suggests such dire predictions are possible.

The next three summers were not quite as bad (leading some ill-informed media plutocrats to declare a recovery was underway), however the recent winter has demonstrated the long term trend of recording breaking will continue and how thin the ice deniers like Murdoch are skating on.

Three years hence, the northern hemisphere winter may well have signified the beginning of  precipitous declines in winter sea ice cover. Likely approaching the annual maximum, Arctic sea ice extent is tracking around 8% below the 1981-2010 average maxima and 2% below the previous low (last year). With global temperatures at a peak, in large thanks to a strong El Nino, Arctic temperatures in this northern hemisphere winters have been “absurd“.

The freezing has most likely stopped and the big thaw is about to commence around 15-20 days earlier than normal. A low trajectory leading into the summer melting provides a high probability of a new record summer low will be ‘achieved’.

Artic Sea ice recording - NSIDC

The Arctic region is positive feedback mechanisms at work in the Arctic (particularly from the reduced albedo) mean the warming will accelerate. The sea ice reforming in the winter is likely to be thinner than ever leading to faster melting in subsequent years and less resilience to stormy weather.

The inevitable summer disappearance of the Arctic ice shelf will have far reaching consequences for the climate of the planet; such is the importance of the cooling effect of the ice. Though science lacks precision in defining exactly how these changes may manifest at a regional level, the changes are likely to be dramatic and far reaching, invoking massive economic costs and human societal dislocation, particularly on northern hemisphere economies as weather patterns shift and events become more intense.

This is a catastrophe unfolding in the timeframe of a generation. So far, the industrial world’s only response has been to gleefully rub its oily hands together race to the pole and start drilling in the now ice-free ocean. We need to do better.

The melting of the Arctic sea ice is seriously big climatic process that is happening very, very fast. It is a very tangible and absolutely indisputable trend. I would hazard a guess the soon disappearance of summer sea ice could well be the talismanic event to wake the citizenry up from its slumber and demand their governments finally stand-up to their corporate laggards.

Perhaps the day the Arctic ice finally melts will be the day we collectively reflect, “whoops, we really screwed-up”.

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