He told delegates that steps such as setting tighter rules on car emissions, regulating for energy efficient goods and building urban mass transit systems are already having an impact that can be measured.

BBC: Climate ship plots course through the battering waves

Charging motorists for scarce road space, with most of the revenues being used to finance improvements in bus, rail or urban mass-transit systems, is the only sensible route to restraint.

ECONOMIST: Roads

That change in perception is providing more momentum for some cities that were already moving away from six-lane highways and suburbs dozens of miles apart, to a series of urban centers connected by light rail and other mass transit systems.

CNN: U.S. cities scrambling to meet rising mass transit demands

Cities around the world have been trying to lure commuters out of their cars and onto mass transit with the aim of making urban life cleaner and greener.

NPR: In Chile, Commuters Sue City over Transit System

Urban planners advise that cities with populations of more than 2 million should have mass transit systems.

FORBES: Delhi's Subway Builder

Granted, it is reasonable enough that most urban transport systems are subsidised, with subsidies ranging from nothing on Hong Kong's Mass Transit Railway to around two-fifths of revenues in Madrid.

ECONOMIST: The end of the tunnel