Create incentives for businesses and local authorities to save energy. The fairest would be a global price on emissions through a trading system. This will take time to achieve and in the meantime national governments can use standards, rules for public procurement or other means to promote energy efficient technologies.

Governments should make energy efficiency a criterion of every project they fund, treaty they negotiate, research agreement they support, school or hospital they build. Others will follow where governments lead.

Politicians should also consider legislation. Australia plans to ban conventional light bulbs and the European Union is likely to follow. Although energy efficient bulbs achieve huge savings, governments have decided it is taking too long for them to dislodge cheaper conventional lighting.

Efficiency standards were raised sharply in the 1970s without harming growth. On the contrary, it has made economies more resilient to the surge in fuel prices in recent years and helping energy efficient technologies will further reduce dependence on energy imports. Only fear is holding us back from taking much firmer action.

The G8 debate on energy efficiency is a positive signal. It is crucial that the leaders do more than pay lip service to it and are bold enough to set their own countries on a course that will make them models for others to follow.