Perspectives on sea ice

[snousle]

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.

Comments

[dorisduke.livejournal.com]

I have not seen this in the mainstream papers. But I do read so many other things I have been following it. I believe the last I read they expect all the ice cover to have gone this year.

[snousle.livejournal.com]

Well, not this year, the decline isn't THAT fast. But we could see an ice-free arctic ocean in about 20 years.

An amusing take…

[ursine1.livejournal.com]

I enjoyed reading the article. It rings true about how "climate deniers" will go to such lengths to discount the obvious. It's like the current conservative diatribe about all those polls showing Obama leading are "skewed". And they forget to mention that the Fox News poll shows similar results. Of course when Obama wins in November, they are all set to claim that he stole the election.

Chuck

[p0lecat.livejournal.com]

You mean the Sacramento Valley well become a inland sea again? I guess this will be number 4.

[snousle.livejournal.com]

Not for at least a few hundred years. But eventually, maybe.

[barbarian-rat.livejournal.com]

Regular news has not covered it much. There are mentions of melting polar ice, but in they're desire to be "neutral" there is little analysis of how this backs up prior forecasts of how climate change will show it's effects.

Melting ice caps and glaciers, drought and record heat in most of the US and ice storms in the upper mid-west and New England are, from what I have read, clearly indications of climate change. the rest of the world is covered in even less detail.

[snousle.livejournal.com]

I would not agree on the "clearly" designation. What we see in todays climate would not be particularly likely if co2 were at earlier or preindustrial levels, but it is not really outside the range of plausible variation. There is some disagreement among scientists on this question, and the media tends to go with the most dramatic pronouncements. Which is a problem unto itself.

The sea ice retreat, however, is wildly out of whack with what we know from the past, though the records are a little spotty, and is likely to create conditions that have actually never been seen before within the decade.

[barbarian-rat.livejournal.com]

I did hesitate on using "clearly".... and you have read up on this far more than I.

From what I recall of the early statements of climate change it was suggested that we would experience several decades of weather fluctuation. Weather events would range from what most people would think of as "normal" to severe. The severe events might all fall within the "normal variation". In addition to the severity of storms, we could experience more storms than we would have otherwise. The amount of storms may or may not fall within "normal variation". It is difficult to determine if climate change is just making storms stronger or if it is causing us to experience more storms, or both. That is were it appears that disagreement among scientists comes in.

From what I see we have a number of severe weather events over the past couple of decades, couple that with retreating glaciers and sea ice and it seems to me that we are in the early states of climate change, thus why I used "clearly".