19 December 2009

First thoughts on the Copenhagen outcome

My preliminary reaction to the outcome of the Copenhagen climate change conference is to be totally unsurprised but seriously disappointed that the assembled leaders were unable to make worthwhile progress on a matter that in general terms has been on the global multilateral agenda since 1992, and in quite specific terms has been on the agenda since the negotiation of the Kyoto protocol in 1997.

I am also struck by the way in which the hothouse atmosphere of these grand multilateral circuses leads normally sensible people to say ridiculous things that should fool no-one. 

As reported on The Age’s website today (see here), President Obama has described the outcome as a “meaningful and unprecedented breakthrough”. Just two little problems, however: it doesn’t get us to where we need to go to avoid dangerous levels of temperature rise (which certainly makes the outcome “meaningful”), and it will not be legally binding. So what we will get is not what we need, but what the national leaders happen to feel comfortable with giving, provided they and their successors happen to feel like delivering on it, which on the track record since Kyoto does not inspire much confidence.

I also think our political leaders owe us all a better and more emphatic explanation of the gamble they are taking with our future. They omit from their language the probabilistic nature of the connection between a level of greenhouse gases in the atmosphere and the resultant degree of global warming.  They speak of a commitment to limit global warming to 2 degrees Celsius, when what they mean is they intend to limit the concentration of greenhouse gases in the atmosphere to 450 parts per million CO2 equivalent.

There is an important difference. We do not know exactly what concentration of greenhouse gases would lead to a 2 degree temperature rise; we can only establish a probability distribution around a central estimate. The central estimate is that limiting the concentration of greenhouse gases to 450 ppm will limit the temperature rise to 2 degrees. What this means is that there is a 50 per cent probability that the temperature rise will be 2 degrees or less. Equally, there is a 50 per cent probability that 450 ppm will result in a temperature rise of more than 2 degrees, and accordingly a substantial probability of the temperature rise reaching 3 degrees, and a finite probability of reaching 4 degrees. Failure to communicate this risk to the public in words of one syllable is criminally negligent.

What this probability distribution means is that if we want to be reasonably sure of limiting the temperature rise to 2 degrees we should at the very least be signing up to the aim of limiting the rise to 1.5 degrees as sought by the representatives of the low-lying states and dismissed in such a cavalier fashion by the rest including our own Prime Minister.

The sin is compounded by the fact that climate scientists whose opinions I respect tell me that there is increasing evidence that any temperature rise over 1 degree will be very problematic. This means that accepting as a target a concentration of emissions that gives only a 50 per cent chance of limiting the temperature rise to 2 degrees would be the height of irresponsibility, even if the assembled world leaders (sic) had accepted emissions targets that would produce that result. And they failed to do even that.

No comments: