Perspectives on sea ice
Not sure how much the regular news has covered the recent arctic sea-ice minimum, but this has stood out as a particularly interesting development in relation to the scenarios forecast in climate models.
In 2006, a review of sea-ice forecasts from several different climate models pointed out that abrupt reductions in sea ice cover are a common feature of those models. The most pessimistic forecast suggested that minimum ice extent might drop below 4 million square km. sometime late in this decade.
The current sea-ice minimum is 0.75M km2 lower than last year, which certainly edges the decrease into the "abrupt decline" category, but does so sooner than ANY model had predicted. The expected consequence of this loss of sea ice is less stability in the polar air mass, which results in greater variability in the weather, including more severe winter storms and longer droughts. It is this increase at the extremes, not the change in average temperature per se, that has the greatest impact on human affairs.
There is a decent chance - maybe 1 in 3 - that the sea ice will bounce back for a few years. But given that the current low is so much lower than the previous record, one would have to conclude that the models have, in this respect at least, been too conservative. It seems likely that this is going to be the "rubber meets the road" moment, when climate change goes from something that can only be measured with scientific instruments and statistical analysis, to something with direct, observable effects on everyday life. If you had asked me last year, I would have expected this to happen around 2030 or later. My current outlook is less sanguine.
An amusing take on how this is likely to unfold can be found here.
In 2006, a review of sea-ice forecasts from several different climate models pointed out that abrupt reductions in sea ice cover are a common feature of those models. The most pessimistic forecast suggested that minimum ice extent might drop below 4 million square km. sometime late in this decade.
The current sea-ice minimum is 0.75M km2 lower than last year, which certainly edges the decrease into the "abrupt decline" category, but does so sooner than ANY model had predicted. The expected consequence of this loss of sea ice is less stability in the polar air mass, which results in greater variability in the weather, including more severe winter storms and longer droughts. It is this increase at the extremes, not the change in average temperature per se, that has the greatest impact on human affairs.
There is a decent chance - maybe 1 in 3 - that the sea ice will bounce back for a few years. But given that the current low is so much lower than the previous record, one would have to conclude that the models have, in this respect at least, been too conservative. It seems likely that this is going to be the "rubber meets the road" moment, when climate change goes from something that can only be measured with scientific instruments and statistical analysis, to something with direct, observable effects on everyday life. If you had asked me last year, I would have expected this to happen around 2030 or later. My current outlook is less sanguine.
An amusing take on how this is likely to unfold can be found here.