Friday, December 19, 2008

Climate change: positive feedback

One of the predictions of climate change scientists is that as arctic sea-ice decreases, the area will warm even faster, as the exposed sea will abosorb more heat.

It's happening:

Dr Stroeve and colleagues have now analysed Arctic autumn (September, October, November) air temperatures for the period 2004-2008 and compared them to the long term average (1979 to 2008).

The results, they believe, are evidence of the predicted amplification effect.

"You see this large warming over the Arctic ocean of around 3C in these last four years compared to the long-term mean," explained Dr Stroeve.

"You see some smaller areas where you have temperature warming of maybe 5C; and this warming is directly located over those areas where we've lost all the ice."

This positive feedback cycle is currently only affecting the arctic - but as the temperature there rises, it will have an increasing effect on the climate of the northern hemisphere. Exactly what it will do, they're not sure - but it will likely affect temperatures and precipitation, and therefore ultimately agriculture.

And meanwhile, the world's government's continue to dither. I don't think we can afford that for very much longer.