I wonder if any else has noticed that we appear to have crossed a threshold in the usage of the phrase ‘tipping point’ in discussions of climate? We went from a time when it was never used, to a point (of no return?) where it is used in almost 100% of articles on the subject. Someone should come up with a name for this phenomenon….
Regardless of the recent linguistic trends, the concept has been around for a long time. The idea is that in many non-linear systems (of which the climate is certainly one), a small push away from one state only has small effects at first but at some ‘tipping point’ the system can flip and go rapidly into another state. This is fundamentally tied to the existence of positive feedbacks and is sometimes related to the concept of multiple ‘attractors’ (i.e. at any time two different ‘states’ could be possible and near a transition the system can flip very quickly from one to another). Another ‘tipping point’ in non-linear systems occurs when as some parameter varies, the current attractor changes character or disappears. However it is currently being used interchangeably a number of potentially confusing ways and so I thought I’d try and make it a little clearer.
[Read more…] about Runaway tipping points of no return

Along with various Seattle business and community leaders, city planners and politicians, a large group of scientists from the University of Washington got a chance to preview the new film, An Inconvenient Truth, last week. The film is about Al Gore’s efforts to educate the public about global warming, with the goal of creating the political will necessary for the United States to take the lead in efforts to lower global carbon emissions. It is an inspiring film, and is decidedly non-partisan in its outlook (though there are a few subtle references to the Bush administration’s lack of leadership on this and other environmental issues).