Re: Ch. 6: Sea ice meltback begins
Chapter 6 – Sea Ice Meltback Begins
“Naturally, given his occupation, Scoresby was ignored by the British Establishment, although he did become a Fellow of the Royal Society.”
I like this sense of tragic whimsy in Wadhams’ writing. Scoresby was a whaler who provided the first scientific analysis of Arctic sea ice in 1820, and whose data led to efforts to reach the Pole, although the first British vessel was forced back by the strong flow of sea ice. In general the Royal Society is immensely prestigious for its superb scientific work, but British class snobbery has immense disdain for mere facts, a sense of contempt that helps to explain why the practical science of climate change gets ignored by the powers that be.
Sealers and whalers continued to track the ice edge, sending their data to the Danish Meteorological Institute from 1872, producing a somewhat patchy historical record of ice extent that showed no clear trends until the recent precipitous collapse. Attention on the Arctic increased with the Cold War as it became the route for missile trajectories between America and Russia, and regular surveys showed summer ice area start to fall from about 1960.
The estimate in the 1980s was a loss of about 3% per decade, but this did not take into account that the ice was also thinning, as Wadhams discovered with his submarine voyages, leading to a paper in Nature published in 1990 showing thinning of 15% between 1976 and 1987. By the 1990s, better measurement methods revealed thinning of a staggering 43% over about 20 years, a volumetric loss of 60%.
Wadhams continues his cantankerous comments about climate modellers, commenting that they failed to recognise the major importance of this finding. Imagine if chicken egg shells thinned by 43%. That was a big factor in the banning of DDT due to its effect on eagle eggs
. We are similarly walking on eggshells with the thin Arctic ice, but in this case the shell still protects the whole planet.
Unfortunately, Wadhams was still ignored by climate modellers, who complacently thought the Arctic ice would remain for the rest of this century. The summer minimum in September fully detached from the coasts of Siberia and Alaska for the first time in 2005, producing accelerating collapse, due to the open seas allowing bigger storms to break up the ice and send it out to the Atlantic.
The idea of studying polar ice by submarine sounds dangerous, and indeed it is. In 2007, two sailors on a British polar submarine were killed by an exploding canister, which should have been replaced already, and Wadhams was lucky to escape alive. That was the last British polar submarine voyage.
The relentless downward trend driven by global warming continues. In 2012, the sea ice summer extent that had been stable above ten million square km for the first half of the twentieth century hit a disastrous new low of just 3.4 million, a third of the previous safe figure, with a strange Arctic cyclone breaking off big chunks. Yet modellers still expected several more decades of summer ice, ignoring the range of accelerating interconnected warming feedback amplifiers.
One of these amplifiers of global warming is the huge new areas of open water that enable the polar winds to whip up big waves in previously icy seas. Polar waves were the topic of Wadhams’ PhD in the 1970s, back when science involved field measurement. Travelling on a diesel sub, he used sonar to show how wave energy scatters when it hits the ice. Now satellite tracked wave buoys show that the autumn refreezing is just not happening as it used to, because this wave scattering is so much more extensive, and because of the heat that has accumulated in the water over the ice-free summer months.