Sunday, 30 December 2012

The Day After Tomorrow

The latest issue of Scientific American provides an excellent summary of the state of the Arctic polar ice cap, or what's left of it.

For those of us concerned about climate change, and everyone else, the ice caps are of tremendous importance. Those vast white expanses reflect most of the sunlight that strikes their surface back into space, whereas the surrounding seawater absorbs most of the solar energy and re-radiates it as heat. The logic is straightforward: more ice = less warming; less ice = more warming.

According to Mark Fischetti's SciAm article, the amount of sea ice that remained after the annual Arctic summer thaw (aka "minimum ice cover") fluctuated around six million square kilometers for the two decades before 2000. Then it began to shrink -due,  presumably to global warming.  When the IPCC published its last assessment report in 2006, the scientific consensus was that the shrinking ice would mean ice-free summers towards the end of the century.

Then something happened. In 2007, the summer melt began to accelerate, and the ice that reformed in the winter was not as thick. Since then the ice has continued to retreat. In 2012 the minimum ice cover hit a record low of 3.4 million sq. km - barely 50% of the average a few decades ago. A few years ago the IPCC thought we'd have an ice free Arctic summer by the end of the century. Now climate scientists think we could see it as early as 2020-2030.

2020-2030!  That's no time at all - practically the day after tomorrow. We don't have much time left if we want to avoid that outcome.

And I do think we should do everything we can to slow the arctic ice melt.  Another article, by Charles H. Greene in the same issue of Scientific American points to more links between climate and weather. In particular, Greene describes how a warming Arctic affects the jet stream and allows it to fluctuate more widely in response to seasonal oscillations like El Nino and the North Atlantic Oscillation. When the jet stream dips further south than normal we get unforgiving wintery weather. When it surges northward we get record heatwaves in March. Given the oscillations currently in place, Greene argues that "the deck may be stacked for harsh outbreaks during the 2012–2013 winter in North America and Europe."

What does a "harsh outbreak" look like? Here's how it looked in Eastern Europe earlier this year, under 10-15 feet of snow:

Not fun. 35 people died in that part of Romania in two days.  Images like that remind me of the 2006 Hollywood disaster flick "The Day After Tomorrow". While that was a movie, and not a prediction, warnings about the near term impacts of Arctic warming are getting worryingly specific.  The lesson- the faster the ice melts, the more things look like a disaster movie.

But catastrophic climate change is not inevitable - not even now, after yet another global climate summit where progress is measured in half-steps. Individuals, businesses, communities and nations can take action now to slow the buildup of greenhouse gases in the atmosphere. Simple no-cost actions to change behaviour, money saving investments in energy efficiency, resilience-boosting renewable energy investments and use of the carbon markets to spur similar measures around the world - all of these make a difference. There is no need to wait for a global treaty in order to set ambitious targets and embrace a lower-carbon future.

We can start today. Or, if you prefer to get things started on New Year's Day, we can start the day after tomorrow.