UPDATE [1.45pm AEST]: And, right on cue, the ABC (Alarmist Broadcasting Corporation) comes up trumps:
The sea ice in the Arctic Ocean has melted to its smallest point ever in a milestone that may show that worst-case forecasts on climate change are being realised, say US scientists.
They say the extent of ice observed on Sunday broke a record set in 2007 and there will likely be further melting with several weeks of northern hemisphere summer still to come. (source)
Batten down the hatches for an avalanche of alarmism relating to the impending Arctic sea ice minimum. It looks to be heading for a record low (although some measures are showing otherwise, see here), and whatever the cause, we will be swamped with links to AGW from the climate science consensus and the media.
And whilst it is at least possible that a proportion of the ice loss is attributable to warming from human emissions, the question, as always, is one of degree: how large are those effects relative to other, natural, forces?
Climate Depot details some of the other factors that may worthy of consideration, before we all leap to conclusions about the role of AGW:
- satellite measurement began just over 30 years ago, and is too short a period to draw such confident conclusions about attribution
- at the time satellite measurement began, Arctic ice had been growing for many years after a period of global cooling, and so a subsequent decline during a period of warming is to be expected
- Arctic likely to have had less ice in 1930s and 40s
- recent ice loss may be attributable to changes in ocean currents, wind or other weather-related phenomena
- this year, a particularly severe storm caused the disintegration of a considerable area of sea ice
- cyclical fluctuations of Arctic ice are known to have existed for millennia
I am not making any claim about the significance of any of the above, other than to say they may play a role.
But unfortunately, the AGW believers invariably insist on using Arctic sea ice levels as a crude “gotcha” to “prove” that they are right (canaries, coal mines etc), claiming absolute certainty of attribution, when in fact, as is almost always the case in these matters, it is a subtle combination of factors that lead to the present conditions.
Just another example of the extreme polarisation of the issues when the middle ground is where everyone should be focussing.