Santa’s relocation or death spiral….

23 04 2013

Another guest post by Mark Cochrane.

Below is the latest update of the so-called Arctic sea ice death spiral. It shows the monthly change in sea ice volume for the arctic region over the last 35 years. For those that don’t know, the amount of sea ice grows and shrinks each year, with increased freezing growing the area covered during the colder months and increased melting shrinking the area covered each summer. If things were climatically stable those would be concentric circles, not a spiral. While the area covered is what is often reported, what has been under-appreciated is the loss of ice thickness that has accompanied the process of melting. Previously, much of the arctic sea ice cover was ‘multiyear’ ice that was thicker due to the amount of time it had been accumulating and the rafting and ridge-forming processes it had been subjected to. Now, most of the remaining ice is being formed each winter and lost each summer. The minimum area covered (Septembers) since 1979 has dropped by 13%/decade. The volume has dropped even faster because warm ocean waters are melting the ice cover from below during the warmer seasons while sunlight melts it from above.

In terms of energetics for climate change, there is another important dynamic at work. The ice cover generally reflects 80% of the incident sunlight while the sea water generally absorbs 80% of the same sunlight. What this means is that for every area of ice cover that is lost, there will be a 4-fold increase in energy uptake during the summer seasons. In terms of temperature the change is more extreme because ice takes 80x the energy to be raised one degree as liquid water of the same mass due to the phase change from solid to liquid as ice melts. Ice acts as a great energy sink, saving up cold from the winter, to moderate any temperature swings in the summer. However, as the ice melts, the energy influx per unit area may increase by only 4 fold but once the ice is gone the heating rate will jump 320 times for the affected areas. More sunlight gets taken up by the ocean waters and it all goes into heating the waters since there is no longer any ice melting (phase change) to be done.

If Waldhams is correct, the Arctic may be ice free during summers within 2-3 years. This happens faster and faster because of the huge swing in the amount of energy pouring into the ocean waters and the thinning of the remaining sea ice. Thinner sea ice is prone to being broken up by winds and waves during storms. Much like crushed ice in your glass, fractured sea ice melts more rapidly.

This is one tipping point that we are already past. Unless we get another dinosaur-killing asteroid or massive equitorial volcanic eruptions, summer sea ice will likely pass into history in the near future. Once it is gone, the ice free period will grow in length year after year as the oceans warm further. This won’t be either subtle or temporary.

Regional weather patterns will change substantially and there is reason to believe that some of the whacked springs of Europe and the US are knock on effects of the melting sea ice. This massive change has alterred the polar jet stream and could (still being argued in the literature) be resulting in more cold air spilling down out of the arctic as the jet stream weakens.

In any case, we need a new home for Santa Claus as the North Pole is no longer a viable summer home. He’ll either need to shift over to Greenland or do a complete Pole shift to the Southern hemisphere.

If anyone doubts that we are fundamentally changing the planet, then book a trip for the North Pole. Study a little history on the furore to find the fabled Northwest Passage then consider that, starting this year, China intends to use the Arctic as a shipping route to the US and Europe –

China to ship up to 15% of trade through the Arctic

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