Furthermore, while CO2 emissions are declining in many sectors, emissions from transport are expected to increase by 57% worldwide between 2005 and 2030. At the rate of growth experienced before the economic downturn, transport emissions will be 120% higher in 2050 than in 2000.
So when an international deal is finally ratified, national governments will need to deliver swift and urgent action on transport if they are to meet their respective targets on reducing emissions. The International Association of Public Transport (UITP) says only ambitious and visionary strategies will produce major change, and suggests that public transport has the competence and ambition to improve the environment for the world's rapidly-growing urban population. It has therefore set the ambitious target of doubling the market share of public transport worldwide by 2025.
"When we first suggested doubling public transport usage in a decade, many of our members dismissed the idea as unrealistic," explains UITP secretary general Hans Rat. "But when we started to list the cities and regions that are already committed to this target we easily counted more than 20. Geneva is planning to double public transport journeys in less than a decade, as is Toronto. Shanghai is a vast city, yet the authorities want to ensure that any destination can be reached in less than an hour. These are bold targets, but cities like Brussels, which has doubled public transport usage in 10 years, prove that they are achievable.
"There are a lot of examples of cities and regions where they are planning to make public transport the primary means of getting around, and that is a very significant change," he adds. "Politicians are taking a much more visionary approach to transport than they were a decade ago. For example, in Strasbourg the mayor wants to reduce speed limits for cars to 30km/h. This will reduce pollution and make public transport a more attractive option."
Rat believes that the current economic uncertainty adds impetus to the argument for modal shift. "I think there are interesting parallels between climate change and the economic crisis," he says. "Climate change is driven by an element of over-consumption - a few generations have burned fossil fuels that took millions of years to produce. It's clear that if we carry on behaving in this way there are consequences for all of us. The economic crisis was also driven by over-consumption. So we're entering an age where there is a strong logic to change lifestyles and reduce consumption, and public transport has an important role to play in this change.
"I think young people are very open to the idea of breaking away from over-consumption and adopting greener travel habits. In recent years, young urban people have become much more open to trains, trams and buses. They still like cars but they are often much more willing to consider alternatives."
But Rat acknowledges the renaissance of public transport is not universal, and while there is evidence of strong modal shift in some regions, the process is much less advanced elsewhere. "In some countries, such as Russia, I think public transport is still viewed by many younger people as part of the older system, whereas private transport is considered aspirational. A lot needs to be done in these areas to raise public transport to the level of technology people experience elsewhere in their lives.
"It's clear that public transport in many cities is taking a hit from the recession as reduced economic activity means less revenue. But many countries, such as France, are making huge investments in public transport as part of their economic stimulus programmes."
The Middle East is fast becoming a world focus for rail investment, and next year UITP will host its 59th Congress in Dubai, a city which exemplifies the transformational effect of public transport in a society previously dominated by cars. The development of Dubai in recent years has been based on private mobility, but as the city grows and land is increasingly at a premium, the authorities recognised the need for more sustainable transport. The city wants to increase public transport usage from 6% of all journeys in 2005 to 30% in 2020, and despite the economic crisis, is pressing ahead with plans for more metro and light rail lines.
"Public transport is now firmly in the mindset of planners across the Middle East, and Dubai's achievements have encouraged other cities in the region to follow," says Rat. "Dubai clearly has economic problems but I think they will work through these issues and go on developing a world-leading public transport system."