Nicholas Stern on a global deal on climate change

The publication of the Stern review two years ago helped shift the climate change debate from science to economics. Climate change sceptics can no longer argue that global warming is a myth or within natural variation: instead, their argument is that it is too expensive to do anything about it right now. Not exactly "wait and see", more "wait until it's cheaper".

Nicholas (now Lord) Stern addressed some of these issues yesterday in a public lecture at the London School of Economics. His timely message was that the current financial crisis is small compared to the havoc that serious climate change will wreak. What havoc? Many things, but the main effects are "all about water". A 5 degree warming (quite possible by 2100 under a 'business as usual scenario') is in the same order of magnitude as the difference between the middle of the last Ice Age and now. The combined effects of rising sea levels and retreating glaciers could force half the world's population to move. Apparently, India is already building a border fence around Bangladesh.

The main focus of the speech was on what a 'global deal' looks like and how we might get there. Stern suggested six components:

1. To stabilise carbon dioxide concentrations at a reasonably 'safe' level of 500ppm, a 50% reduction in greenhouse gas emissions (compared to 1990 levels) by 2050. This probably means an 80% reduction in developed countries and more in the USA.

2. By 2050, 8 billion of the world's 9 billion people will live in developing countries. So developing countries must lead the deal, because it will be their world. We cannot force them to cut emissions: they should be forcing us to show them how.

3. Markets and carbon trading will be essential to get reductions at the lowest possible cuts. There will be some exceptions at first to bring people on board (steel? aviation?) but we should aim to phase them out.

4. Whatever targets we set for emissions reduction, we need to stop deforestation quickly. There are lots of ancillary benefits to this (flood control, biodiversity) but it will have to be combined with development. "Climate change and development are deeply linked - if we fail on one, we fail on the other".

5. Technology: nothing should be ruled out, including carbon capture and storage (CCS) and nuclear power. This was controversial with the audience at LSE, but Stern held his ground: we need to try everything, fast, to figure out what works.

6. Adaptation: poor countries will be hit first and hardest. We urgently need to work out how to get low-carbon development in an increasingly hostile natural environment.

The rest of the speech concerned how to put together this global deal and the research programme needed to support it (this is a university, after all). "Surely the global financial crisis shows us what happens if we become aware of a serious risk and don't deal with it".

Some of Lord Stern's targets are being adopted by politicians. Barack Obama has spoken of an 80% reduction in greenhouse gas emissions by 2050; Gordon Brown has committed the UK to doing the same (though he's trying to wriggle out by excluding aviation - see here). What about the developing world? "Attitudes in China and India have changed a lot in the last 2 years, though there is still justified anger at the hypocrisy of the 'rich countries'."

It seems it always requires a disaster (Katrina? Lehman Brothers?) to shake politicians into action. Sadly, at the current rate we are going to need a few more disasters before the key players, China or the USA, take serious action on climate change.