You know that a major shift in the political climate has taken place when the leading champion for the environment wins the Nobel Peace Prize.

Mr Al Gore, who "used to be the next President of the United States", will share the prize with a United Nations panel that helped turn environmental concerns into security ones.

Its work has raised awareness that the climate changes that might arise from global warming could have serious security implications, from the displacement of peoples to clashes over resources.

Similarly, a recent roundtable on the environment here saw the usual subjects being tossed up for discussion. But the topic that generated the most debate at the forum was how to make the transport system not only more efficient, but also more environmentally sound.

Better town planning, providing for more integration of commercial and residential functions, for example, would help by cutting down the need for people to travel.

Some felt that much more could be done in Singapore to promote the use of public transport, by making it more convenient and financially attractive. Professor Euston Quah from Nanyang Technological University said that rises in ERP charges had not kept pace with falling car prices and vehicle taxes, tilting the consumer calculus in favour of greater car usage.

No one wants driving in Singapore to be less efficient in order to promote public transport. But perhaps more could be done to tip the balance in favour of public transport. Investing in a denser network of MRT lines with more stations is a path that is rightly being pursued for economic reasons, but might also be supported for environmental ones as well.

Why stop there? Why should the state not encourage bus and taxi companies to go green, putting more hybrids or compressed gas vehicles on the road, for example? Singapore's transport planners used to set their sights on building a world-class transport system. But good and cheap public transport is no longer enough. These days, it also has to be one which is green, or environmentally sound. In other words, not just world-class, but planet-saving too.

Turn environmental concerns into security ones

They had to. People did not listen when they were just environmental concerns; when they were presented as economic and security problems, the world started to take notice.

Clashes over resources

All human history has been about clash over resources, whether it is land, oil or people's minds. And as resources diminish - as fresh water is likely to - there will continue to be areas of conflict.
how to make the transport system not only more efficient, but also more environmentally sound

Some argue that Singapore is too small to make a difference, but that is not the point. The island can be a test case of how to do things better - already we export expertise on housing and reclaiming water, for example, to bigger countries.

Greater car usage

ERP has boosted car ownership by keeping the traffic flowing. Transport Minister Raymond Lim said: "The use of ERP to manage traffic has made it possible for more Singaporeans to own cars than we otherwise could, and our vehicle population has grown from 680,000 in 1997 to 800,000 in 2006."

Good and cheap public transport

Good and cheap would actually be enough to drive people out of their cars, as long as it is better and cheaper than it is today. Public transport needs to be a much better choice - and even then, some people will still want to be sealed off from their fellow men inside their cars, and will pay whatever price they need to.