Cities have become the new testing grounds for international climate policies. This is where smart green ideas in the transport sector are developed and implemented - often with encouraging results.
Copenhagen is known as the most bicycle-friendly city in the world
Global climate policy is usually dominated and steered by countries and international organizations. But, as the climate change summit in Copenhagen last year showed, there's a new player on the global stage - cities.
For the first time, a group of city mayors met for their own summit in the Danish capital last year. They made clear that much of the policies for combating global warming now depends on them. Cities make up 80 percent of global energy needs. And they are responsible for 75 percent of global greenhouse gas emissions.
"That's why cities must take a leading role in climate protection - they don't just contribute the most to climate change but will also feel the impact of it the most," Reinhold Achatz, head of the research department of engineering giant Siemens, who studies urban climate policy, said.
Cities make up just three percent of the earth's surface, but half of the world's population lives in them. The United Nations estimates that by 2030, that figure will rise to 60 percent, or five billion people.
Some mega-cities such as Delhi struggle to combat traffic congestion
The growing urban population causes many problems: high energy consumption, worsening traffic and growing demand for water. Since 2006, a group called Large Cities Climate Leadership Group (C40) - an alliance of 40 metropolises - has been grappling with the problems. The idea behind it is that cities can learn from each other and raise their lobbying power at international climate negotiations.
Large cities are ahead of the game particularly when it comes to transport policies. One of the leaders is the global "cycle capital" Copenhagen, which has been promoting the use of bicycles since the 1960s.
"Some 37 percent of our commuters ride to work on bicycles. We want to build bicycle paths all over the city. Only a few street sections don't have bike lanes," Lasse Lindholm, a spokesman for Copenhagen's city government, said.
The city's bicycle-friendly policies include a city-wide bike rental system and large bike parking lots. It's triggered a number of copycat efforts in Barcelona and Paris, which are expanding their own city bike rental programs.
Promoting bicycles is a vital part of transportation policy in cities such as Stockholm, Amsterdam, Vienna and Oslo, which are considered particularly environmentally-friendly in Europe.
Green is the way to go
Mexico City, too, is expanding its bike rental system together with pedestrian zones, modern and high-speed bus services, new bus lanes and a subway line. The mega-city plans to invest a billion dollars per year on it.
The Colombian capital Bogota is already reaping the benefits of expanding its public bus services. It's estimated that it's cut travelling time for commuters by more than 30 percent and lowered carbon emissions by 300,000 tons a year.
London has managed to bring down its greenhouse-gas emissions by 16 percent ever since it introduced an inner city car toll in 2003. That has also reduced motorized traffic by 20 percent. The car toll has earned the city almost 140 million euros, which it has partially invested in the expansion of its public transportation network.
Stockholm has now followed suit and introduced a similar car toll in 2007. At the same time, the Swedish capital has outfitted its busses with hybrid engines, biogas or ethanol. That's one of the reasons why Stockholm was declared the "European Green Capital" 2010 by the European Union.
Hamburg eyes ambitious climate targets
Next year, Hamburg is to get the title. One major reason is the northern German city's green transport policies. For most people in the city, the next bus or train stop isn't more than 300 meters away. Two busses with diesel hybrid engines already ply the roads - eight more are planned.
Hamburg has one of the best public transport systems
"We're now massively expanding our bicycle transportation network," said Volker Duman, a spokesman from the city's environment agency. "And Hamburg's regional train network only runs on green energy from hydropower - the first German rail company to do so."
The city is hoping to achieve an ambitious climate goal - it plans to slash carbon emissions by 80 percent by 2050.
It's already taken a first step toward that goal. The city's per-capita emission rate has already sunk 15 percent compared to 1990 levels.
"It's a significant success for the city," according to the EU Commission.
Author: Torsten Schaefer (sp)
Editor: Jennifer Abramsohn