Leading article: The blame game and a plan for the future

It is impossible to state unequivocally that the floods that have caused such misery in parts of England over recent days are a direct consequence of accelerating climate change. Flooding is not a new phenomenon in the UK. And the waters have risen to such levels in the past. There will inevitably be those who argue that this is part of a normal cycle. But regardless of whether this latest misfortune is a result of global warming or not, all the scientific climate projections tell us that we can expect more of these sort of extreme "weather events" over the coming century.

When we talk of the effects of runaway climate change, we tend to focus on such effects as the melting of the polar ice caps, the disappearance of glaciers, global crop failure and desertification. But another consequence of a warmer world will be an increase in the number of storms, hurricanes and typhoons. These will be more powerful too, creating vast amounts of rain and flooding.

We have no excuses for underestimating the damage this will inflict. As this weekend's events show, flooding threatens a vast number of houses and businesses. It can severely disrupt the transport system, as the wretched experience of drivers on the M5 at the weekend attests. And the contamination of our water supplies is also a serious risk, as the ominous warning by East Surrey Water for customers to boil their water demonstrates. We have not yet seen flooding damage our electricity supplies, but with a significant number of power stations sited in coastal areas, it would be folly to ignore the possibility.

The economic cost of future flooding could be colossal. The Association of British Insurers predicts that by 2080 global warming will have increased the annual cost of flooding in Britain by almost fifteen-fold, potentially up to £22bn. Globally, the cost is likely to be even greater. Sir Nicholas Stern's report on the economic effect of global warming for the Treasury calculated last year that 5 to 20 per cent of the world's economy could be wiped out by a combination of drought, floods, water shortages and extreme weather.

The Conservatives have rushed to blame ministers for the damage caused in the immediate crisis, but there does not seem to have been much more that the Government could have done, beyond perhaps a greater provision of sandbags and portable defences. It is impossible for ministers to predict exactly where it is going to rain. The official response in such instances is always going to be mainly reactive: airlifting people out of danger and providing temporary accommodation to those affected.

The Government's fundamental responsibility lies in planning. It has a duty to invest properly in flood defences. The National Audit Committee found last month that defences in some parts of the country are not in a satisfactory condition. That is clearly something that needs to be put right. Another official responsibility is to regulate the level of new building on flood plains. Yet the Government proposes to construct 200,000 more homes in the South-east, many on land prone to flooding. The Government has a stark choice. It must either invest vastly more in flood defences, or ensure that these homes are built elsewhere. Ministers can no longer get away with treating building and flood protection as unrelated areas of policy.

But most important, the Government must push through a global treaty to bring down global carbon dioxide emissions from industry and transport. In the long term, this is our only hope of protection. This weekend we received a mere taste of the chaos and trauma that climate change will bring in its wake. Unless we act now, there will be far worse extremes of weather to come.