Perhaps the most visible sign of climate change is the Arctic's shrinking sea ice cover. Concerns are growing that we are reaching a point at which the transition to an ice-free Arctic Ocean in summer becomes a rapid one.
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Even our early climate-change models developed in the late 1970s told us that the Arctic would suffer most from the surface warming that came with adding carbon dioxide to the atmosphere and that this would be intimately tied to the shrinking of its sea ice cover.
This is called Arctic amplification and when we look at our climate records, that is exactly what we see: the climate warming, with the strongest rises in temperature in the Arctic, and those rises linked to the loss of sea ice cover – just as projected 30 years ago.
In other words, even the crudest climate-change models worked quite well here - something that those who cling to the hope that they are "only" models might like to bear in the mind for the future.... (Via DeSmogBlog.)
You could sail through the Northwest Passage in 1906, ie. north around North America.
ReplyDeleteThe poles shrink form time to time, it happens.
Er, this is "ice-free" as in none, not even a snowflake - not just a convenient north-west passage. Moreover, positive feedback loops mean that it will probably mean none for more and more of the year....
ReplyDeleteOh. It's much worse that that...
ReplyDeleteIf the Arctic ice does melt away, it is thought that it will cause enough de-salination of the Atlantic to stop the Gulf Stream. This means our winters here in the UK will get like Canada's.
It has happened before (apparently) and when the Gulf Stream switches off it happens *very quickly*.
Cheer up!
Indeed: I didn't want to, er, depress people....
ReplyDeleteThe other 'fun' possibility is if the desalination of the Atlantic manages to stop the North Atlantic conveyor. If that happens the life as we know it ceases to exist. Apparently, this has also happened in the dim, distant, past.
ReplyDeleteLuckily, that eventuality is meant to be 'fairly' unlikely!
I'll draw what comfort I can from that....
ReplyDeleteFrom the graphs I've seen I'd would say 'even the crudest models' were way off mark: they seem to be seriously underestimating the shrinkage.
ReplyDeleteIt looks like the relationship is cubic not quadratic.
All I can say is thank goodness for lousy economic theory - at least this global crash may give us breathing space and in 5 or 6 years time when the economy starts to 'recover' the evidence will be too loaud to ignore.
It's particularly unfortunate that sceptics never consider the possibility that the models may indeed be inaccurate but, as you say, the *wrong* way - i.e. things are even worse.
ReplyDeleteI'd like to believe the current economic crisis will have such a nice knock-on effect; unfortunately, I fear it will just lead to more compromises (hello, EU) and corners being cut...