Sir

Your Editorial “Carbon impacts made visible” (Nature 429, 1; 200410.1038/429001a) mentions two bottom-up opportunities that need to be seized if we are to reduce the causes of climate change. But you omitted another, possibly more significant, one that is already happening.

Since 1993, local governments in towns, cities and municipalities around the world have been signing up to their own Kyoto-like commitments, largely as part of the International Council for Local Environmental Initiatives programme, “Cities for Climate Protection” (http://www.iclei.org). At the last count, almost 600 had signed up. In the United Kingdom, 60 towns and cities, including Middlesbrough, have signed up to a similar programme, under the Nottingham Declaration on Climate Change. Added together, these communities produce nearly 10% of the world's greenhouse gas emissions. So these community-level targets should not be ignored.

Local governments are well placed to get to the nub of the problem in a way that global treaties and carbon trading can never achieve. They can get the message across to the residents, shopkeepers and drivers of the world that efficient, cheap-to-run homes, fridges, cars and so on can improve their quality of life while helping a global cause. Also, people can take action locally regardless of national priorities: witness the wealth of climate-friendly activities going on in many US cities despite the now infamous anti-Kyoto stance of the Bush administration (see Earthed 9–11, May 2004).

So in an age when the power of communities seems to be shrinking against the might of world governments and multinationals, it's refreshing to see that bottom-up local action still has an important part to play in tackling climate change. Power to the people indeed!