Scary Pictures from NASA

We used to talk about climate change as a “slow motion catastrophe” because we thought its consequences were still far of in the future. But the blandly titled “Sea Ice Conditions: Multimedia Presentation” from NASA makes it clear that we need serious action now.

The key bit for me was the acceleration of melting of the Arctic ice. If you check out the description Figure 3, you’ll see that “Monthly irregularities in ice area from November 1978 to February 2008 are shown. The overall trend is -4.4 percent per decade but there appears to be an acceleration in the decline from 1996 to 2008. The trend from 1978 to 1996 (in green) is shown to be -3 percent per decade while that from 1996 to 2008 (in blue) was -10.7 percent per decade.”

Why does this scare me?

Well, check out Figure 14: “Polar ice reflects light from the sun. As this ice begins to melt, less sunlight gets reflected into space. It is instead absorbed into the oceans and land, raising the overall temperature, and fueling further melting. This results in a positive feedback loop called ice albedo feedback, which causes the loss of the sea ice to be self-compounding. The more it disappears, the more likely it is to continue to disappear.”

The Arctic is, essentially, one of the great control valves of the climate. And we – in the immortal words of Spinal Tap – have cranked it up to 11. Granted, the knock-on effects of this accelerating cycle are by their very nature difficult to predict, but they are keeping a lot of scientist up at night and should have politicians leading a charge for climate action.

If you don’t want to try to read between the lines of NASA’s rather dry report of the facts, take a look at this study published last month in the Proceedings of the National Academy of Sciences. It ranked the disappearance of Arctic sea ice at the top of their list of potential “tipping points” in the climate system, where things don’t change gradually but jump quickly from one state to another. As these eminent researchers put it:

“Society may be lulled into a false sense of security by smooth projections of global change. Our synthesis of present knowledge suggests that a variety of tipping elements could reach their critical point within this century under anthropogenic climate change. The greatest threats are tipping the Arctic sea-ice and the Greenland ice sheet, and at least five other elements could surprise us by exhibiting a nearby tipping point.”

Let us not be lulled.

by Keith Stewart