We've seen Al Gore's movie and read Sir Nicholas Stern's report — now it's time for legislation. The Government has proposed a Bill to address climate change, but will it produce a robust and viable framework for addressing what Tony Blair describes as "the greatest long-term threat to our planet", or will it prove to be another vague and vacuous exercise in PR and politics?

The Government has indicated that "legislation will be introduced as soon as Parliamentary time allows", although it seems likely that something will be included in the next Queen's speech on Wednesday, November 15. We are also told that "the widest possible debate across the country and in Parliament" will be promoted, suggesting there is still a lot to play for, both inside and outside Whitehall.

The Bill is partly a response to the Stern report, which reiterated what scientists and economists on the International Panel on Climate Change have been saying for several years: "Climate change presents very serious global risks, and it demands an urgent response…it is the greatest and widest-ranging market failure ever seen…" However, any Government action could also be seen as a means of jostling for green political space with the Conservatives, who have already produced their own Bill, apparently with the support of Friends of the Earth.

Tony Blair has so far declined to comment on the content of the Bill, although he did suggest it would have to be "practical and workable". Various other vested interests inside Government will also have strong views, especially at the Treasury. David Miliband, the Environment Secretary, has taken the lead by outlining four key elements for the Bill: (1) statutory endorsement of the Government's long term emissions reduction goal of 60 per cent by 2050, along with interim reduction targets on a ten yearly basis; (2) setting up an independent "carbon committee" to advise the Government generally on its climate policy; (3) enabling powers to provide more detailed mechanisms in secondary legislation; and (4) improved monitoring and reporting arrangements (including to Parliament).

A legal blank canvas may seem like a good stepping stone towards addressing what is obviously an extremely problem-packed and contentious global issue. However, without more legislative "what" and "how" to add substance to the "where", we could end up with a rather empty measure that only takes up valuable legislative time while the "real deal" has still to be properly formulated.

In some respects, the Bill will only cover old ground. The Climate Change and Sustainable Energy Act 2006 came into force in August this year. It was promoted as a private members Bill and places a duty on the Government to report annually on the level of greenhouse gas emissions and the related mitigation measures being taken in the UK.

The Office of Climate Change has recently been set up and, according to Department for Environment, Food and Rural Affairs, will provide "a shared resource for analysis and development of climate change policy and strategy" across Government. It will function separately from the Carbon Trust and the Climate Change Programme Office. The EU Emissions Trading Scheme operates under existing enabling powers and already imposes significant annual emissions reporting requirements on the UK.

What the Bill really needs is some legal bite. Long term binding targets should be supported by intermediate milestones (perhaps on an annual basis), so that the Government can be held accountable. Penalties could be imposed on Ministers who fail to meet these targets. Detail on the delivery mechanisms should not be left to secondary legislation, as this just postpones the difficult decisions on allocating responsibilities.

An even more progressive approach would be for the independent climate change body to operate in an analogous fashion to the Bank of England Monetary Policy Committee, by setting emission reduction targets in the UK in the same way that interest rates are now fixed. Such measures could have a real impact in practice, though careful consideration would need to be given to ensure tie-in with action at the European level so that impacts on competition are minimised.

It can be expected that many of the financial impacts flowing from any new legislation will fall on business. In making decisions, business is often willing to accommodate new regulatory burdens provided the Government can deliver a long term legislative landscape based on clarity and certainty. However, such legislation in turn needs to be premised on cogent policy that has sufficient public support. By contrast, legislation that is rushed through without a firm policy foundation may only give rise to a Pandora's box of legal risks and ineffective outcomes.

Climate change is now recognised as a hugely difficult and serious problem which demands a comprehensive and substantive regulatory framework to address the inevitable economic and environmental impacts. But new legislation must be driven by a clear policy vision of what can and should be done, and not by political short-termism. Hard political decisions are no excuse for making soft law.

Michael Woods is head of the environment group at the international law firm Stephenson Harwood