Our Melting Planet

Due to declining ice coverage in the Arctic, the NOAA is being forced to quickly generate maps of previously uncharted Arctic waters for commercial vessels. Meanwhile, John Timmer talks to geologist Richard Alley about glacial melt in the Antarctic:

The key thing that regulates the flow of these glaciers is what’s called a “grounding line,” or the place where the glacier’s end is in contact both with the ocean floor and with the ocean itself (this is in contrast to the floating ice that sometimes spreads past this site). While a glacier is on the grounding line, Alley said there are a lot of feedbacks that tend to keep it there. … The problem is that, when the feedbacks are finally overcome, the grounding line fails catastrophically, and the ice tends to retreat rapidly to the next potential grounding line.

Alley identifies areas in which this effect could “raise sea levels by two meters”, faster than we would be able to adapt. Unfortunately, worldwide concern about the need for action on climate change is fading:

Despite years of studies showing the impact of global warming on the planet, only 49 per cent of people now consider climate change a very serious issue – far fewer than at the beginning of the worldwide financial crisis in 2009. Worries about climate change first dropped in industrialised nations but they have now also fallen in developing economies including Brazil and China, according to the survey by GlobeScan Radar.