For many people in Germany and beyond, Freiburg stands as a vision for a more environment-friendly future. The picturesque city of 200,000 people in Germany's south-west is a magnet for visitors interested in finding practical answers to the questions posed by climate change, says Dieter Salomon, the city's mayor.

“We have delegations from Japan, South Korea, India and elsewhere – and interest is growing all the time,” says Mr Salomon, whose own background reveals how environmentally conscious Freiburg is. Elected in 2002, he was the first mayor of a large German city to come from the small Green Party.