In a ceremony in Brussels on 10 February, nearly 300 cities will pledge to go beyond the EU target of a 20% reduction in CO2 emissions by 2020. They include large cities like Bielsko-Biala, Budapest, Hamburg, Lisbon, Madrid, Riga and Zagreb.

The covenant of mayors will take place during Europe’s annual conference on sustainable energy, a showcase for new trends in low-carbon technology and renewable energy. The largest of the events taking place in 52 European cities during sustainable energy week (9-13 February), the conference also boasts an awards ceremony for the most innovative projects.

Some cities are already well on their way to reaching the 20% target. One of the most active, the German city of Heidelberg, has set up an agency to advise residents on how to save energy. “The last 10 years we reduced nearly 40% of our CO2 emissions in our city facilities,” says Eckart Würzner, Heidelberg’s mayor.

The Brussels conference comes just two months after EU leaders signed off on a comprehensive package of measures for lowering Europe’s contribution to climate change. The most far-reaching reform ever of European energy policy, the plan aims to make Europe the world leader in renewable energy and low-carbon technology. This will help shelter the economy from the effects of rising energy prices and uncertain supplies. 

Energy prices in the EU rose by an average of about 15% in 2008, partly in response to growing demand from developing countries like China and India. More than 50% of the EU's energy comes from countries outside the bloc – and the dependence is growing. Much of that energy comes from Russia, whose disputes with transit countries have disrupted supplies in recent years. The latest cutoff, in January, lasted nearly two weeks.