Big cities are increasingly taking the lead in the fight against global warming. As heavy emitters of greenhouse gas, some are going beyond federal or national political efforts to deal with the climate-change challenge. In the US, the mayor of Seattle has been joined by more than 400 other city mayors in the US Mayors' Climate Protection Agreement. 1990 levels by 2025.

The main policy measures foreseen in the plan are:

  • A Green Homes programme, including large subsidies for home insulation and a special service to help Londoners implement energy-savings in their homes;
  • a Green Organisations programme, targeting the commercial and public sector with the aim of implementing energy-savings in buildings by turning off IT equipment and lighting at night;
  • a Green Energy programme aiming at moving a quarter of London's energy supply away from the national grid and onto local decentralised systems by 2025 (mainly via CCHP, combined cooling heat and power), and;
  • a Green Transport programme providing continued investment in public transport, walking and cycling, promoting low-carbon vehicles and full-carbon pricing for transport (highest-polluting vehicles would pay 25 pounds sterling per day and zero-emission vehicles would travel free).

A noticeable ommission in the London Climate Change plan is aviation. With several airports, aviation accounts for one third of London's CO2 emissions, but the city has little grip on this sector. Therefore the only measures it can advocate in the plan are support for EU efforts to curb emissions from aviation, a promise to challenge further runway expansion at UK airports and educating Londoners to use alternatives to air travel.