The UK government clearly aimed to make a statement about climate change last week. And it succeeded. At the Queen's official opening of parliament on 15 November, it promised legislation that will see the country's greenhouse-gas emissions slashed to 60% of 1990 levels by 2050. That is a level far beyond its carbon-reduction commitments under the Kyoto Protocol, and a longer-term programme of cuts than any other major polluting country has so far adopted.

Is the British pledge as impressive as it sounds? The legislation has not yet been officially introduced into parliament — that will happen in the coming months when the government produces a draft bill. So, although the announcement is a powerful statement of intent, the details remain vague. “How the target is defined and set, and how progress is measured and reported, are fundamental issues that are still being considered,” said a statement from the Department of Environment, Food and Rural Affairs, which is charged with drafting the legislation.

Opposition politicians and environmentalists have also pointed out that although the far-reaching target is laudable, the plan isn't so tough in the short term. Critics have called for the plan to involve fixed annual cuts in emissions, rather than the five-yearly targets suggested by the government. There is optimism, however, that the target is achievable — if improvements in energy efficiency are combined with the development of low-carbon technologies.

Unfortunately the same cannot be said of sorting out what should happen in the next phase of the Kyoto agreement. International talks in Nairobi, Kenya, last week were meant to address how to incorporate large developing economies such as China, India and Brazil into the treaty after 2012. On Friday, the summit's final day, the Kyoto nations decided to postpone the negotiation until 2008.