Let’s get this one over with. Arctic ice seems to have bottomed out on 9 September, about two weeks earlier than usual. 2011 was the second lowest on record by a thin margin. I’ll freeze the graph here for the record:
Here’s the important bit:
The last five years (2007 to 2011) have been the five lowest extents in the continuous satellite record, which extends back to 1979. While the record low year of 2007 was marked by a combination of weather conditions that favored ice loss (including clearer skies, favorable wind patterns, and warm temperatures), this year has shown more typical weather patterns but continued warmth over the Arctic. This supports the idea that the Arctic sea ice cover is continuing to thin. (Emphasis added)
New research on Greenland ice
A new study has found that crevasse areas have increased by about 13% from 1985 to 2009. The effect of this seems to be to decrease ice sheet sliding but to increase melting. The latter is the more important effect.
What this means for ice sheet dynamics and sea level rise is not yet clear.
There’s more explanation here.
Meanwhile Andrew Revkin has queried a bunch of scientists on their current views on sea level rise and will let us know when he gets time.
Furthermore, according to this site (and I understand that’s right) it takes 360 of them to raise the sea level one millimetre. The oceans all up contain 1.37 billion cubic kilometres of water.
Bad weather and AGW
Kevin Trenberth has said:
It’s not the right question to ask if this storm or that storm is due to global warming, or is it natural variability. Nowadays, there’s always an element of both.
He’s also suggested that the likes of Roger Pielke Jr. and Judith Curry should prove that there has been no human influence. That’s what the appear to be suggesting. Let them prove it.
Gore impresses Tamino
I didn’t watch the Climate Reality broadcast, but Tamino did and was impressed. This much is settled about the science, he says:
Global warming is really happening.
It’s caused by human activity.
It seems Gore has rounded on the deniers, “exposing their tactics, their folly, and their lies.” They don’t like it. Tamino reckons they are getting desperate. In the program
the message came through loud and clear: the reason we’re not tackling this problem seriously is the denial campaign, which creates confusion with nothing but a bunch of red herrings.
Oreskes on Merchants of doubt
She says that in the peer reviewed literature there is essentially no debate about the validity of AGW.
I’ve previously linked to her radio interview with Richard Fidler.
Geoengineering trials have begun
Various methods geoengineering are being trialled, according to the New Scientist. At Bristol university, for example, they are hitching a kilometre-long hose to a balloon and pumping water vapour into the sky. David Keith from Harvard University thinks using aircraft would be more effective as well as cheaper.
Other methods include spraying seawater into the clouds to make them whiter. Gavin Schmidt of NASA suggests that these experiments may be a waste of time.
Schmidt says that what we need is not field tests, but better modelling studies. Most simulations of geoengineering are “naive”, he says, and cannot model all the possible side effects. “People are not doing the right kinds of experiments to assess these effects,” he says.
Climate change and refugees
A couple of weeks ago Marcus Stephens, President of Nauru, wrote about climate change and security making mention of anticipated floods of climate refugees and linking to this report by the International Organization for Migration.
Some of the most vulnerable don’t move, but then if they do further distinctions need to be made between voluntary migrants and refugees forced to leave. Also, not everyone who moves will leave the country of origin.
The usual figure given is that there will be 200 million migrants by 2050. The report says, we don’t know, the figure could be anywhere between 25 million and a billion.
I note the report was published in 2008. Does anyone have more recent or more definitive information?
Two figures I heard recently (no guarantees about accuracy):
1. A one metre sea level rise would displace 37 million people in our region.
2. There are currently 4 million refugees in our region.