Summer is the period when sea-ice reaches it’s minimum extent in the Arctic, but thanks to climate change this extent has been declining rapidly.
There are signs the Arctic is approaching a death spiral, when the Arctic will be ice-free during the summer months.
This will have profound effects on the planet’s climate.
As Robert Scribbler notes in his blog the past few weeks have been concerning:
Over the past month, warmth and energy have been building in the Arctic. All around, from Siberia to Scandinavia to Alaska, heatwaves have flared beneath anomalous long-wave patterns in the Jet Stream. Patterns, that in many cases have persisted for months. The Alaskan heat dome sent temperatures there to 98 degrees (Fahrenheit). Temperatures in Siberia flared to the low 90s. And heat built and flared again in Scandinavia and Northeastern Europe, sending Arctic temperatures first into the 80s and then to 92.
This building and highly anomalous heat was coupled by another unusual event — a long duration series of Arctic storms that have thinned and weakened large sections of sea ice near the North Pole. This Persistent Arctic Cyclone has flared and faded, remaining in the Arctic since late May.
Now, with central sea ice weakened and with heat circling in from all around, the Arctic appears to be bracing for a period of rapid sea ice loss.
Last year we saw a record decline in sea ice. This year’s decline did not seem as precipitous, tracking slightly below the 1981-2012 average extent and within standard deviation.
As the above graph from the US National Snow and Ice Data Center indicates, the trend of the past few weeks looks worrisome.
A sharp decline is obvious, pushing it closer to the 2012 record minimum – though I hasten to add within the standard deviations.
Noise or signal?
Hard to say at this point, but I’ll be watching the trend over August. What ever the outcome, low and declining sea-ice extent during the summer months can be considered “the new normal”.
Tipping point cometh?
The oceans cover 70% of the planet’s surface, and are a crucial component of the climate system itself.
But at some point the oceans will stop soaking up the extra heat/energy we’re adding to the climate system.
Like a slowly boiling jug of ice water, we’ll reach a tipping point.
At first the temperature rise is imperceptible.
Slowly the heat builds – slowly the ice begins to melt.
Linear – manageable.
To preserve the ice, one merely has to remove the source of the heat.
But what if you don’t?
What if you continue to expose the contents of the jug to the same – or increased – levels of heat?
Slowly the heat builds – slowly the ice melts.
But there comes a point when the ice is gone.
A tipping point is reached and passed.
Within moments, the water reaches boiling point.
This simple brute fact of physics is now playing out in the Arctic.