David King: There's no avoiding it. Tackling climate change costs money

Spending now will help secure the future for our grandchildren

In the Oxfordshire town of Abingdon, close to where I live and work, a bridge is being demolished to reduce the risk of flooding to nearby homes. The removal of this footbridge, across the River Ock, will ease the flow of water when levels are high.

The blockage created by this bridge caused severe flooding in 2007, the year when 13 people died and thousands of other buildings across western and central England were inundated, in some of the worst floods we have seen.

Climate change is raising sea levels and making storms and serious flooding more frequent, and much work has been done since 2007 to protect our most vulnerable homes and businesses. Floods that today we would expect only every 150 years could hit us every 10 years by 2100, if we do not significantly cut carbon emissions. Vast areas of Britain will be at risk.

This threat was highlighted in 2004 in the Government's Foresight Future Flooding report which I led, working with more than 100 other experts. We warned that four million people and properties worth £200bn were at risk over the next century from flooding and coastal erosion caused by climate change.

The report also said that economic damage could be cut by between 40 and 70 per cent if investment in flood management was sufficiently increased. We found that for every £1 spent, £8 could be saved in the future, although that depended on the Government substantially increasing funds for flood protection.

As a result of this report, spending was increased to £800m annually on flood management. Despite that, we were still suffering £1.4bn worth of flood damage every year. Damage is caused not only by overflowing rivers and eroding coasts, but by the inability of sewerage and drainage systems in towns and cities to cope with sudden downpours. As climate change bites, these downpours will occur more often but sewers and drains won't be up to the job.

Now, the Government is looking again at how much it spends to protect us from flooding, and £800m annually is nothing like enough. More money is needed to protect against the effects of climate change – rises in sea levels, coastal erosion, the increasing frequency and severity of storms and a predicted 20 per cent increase in river water. Alongside that is the demand for new homes, some of which could be built on flood plains.

In July 2007, ministers increased flood defence spending by £200m in response to the floods of that year. And less than four months ago, the Government promised a multi-million package of measures including a flood forecasting centre, specially adapted homes, new rescue boats and money for local authorities to take control of flood management.

This more recent allocation was in response to the Pitt Review, which followed the 2007 flooding disaster and updated our 2004 warnings. It found that climate change could cause even greater sea-level rises and even more frequent storms than we feared five years ago. It called for between £1bn and £2bn to be spent annually on flood management over the next 50 years and up to £800,000 each year on drains and sewers.

I wholeheartedly agree with Pitt's recommendations: even if we meet the strictest targets for cutting emissions, we will still need this level of investment because reducing greenhouse gases will take about three decades to have effect.

Governments are detailing their economic stimulus packages aimed at helping us out of our dire financial straits with varying portions of these packages being earmarked for green investments – to rejuvenate renewables' industries, develop cleaner vehicles and fuels, and create jobs in businesses for which climate change is an opportunity.

Investing more in flood protection should be part of those packages and is crucial if we are to save money in the future. Spending now means helping secure the futures of our grandchildren. Unblocking the River Ock to help the people of Abingdon is one small, but essential, good turn done. The Government must allocate enough money for thousands more good turns like this. If it does, it will leave a truly sustainable legacy for generations still to come.

Prof Sir David King is Director of the Smith School of Enterprise and the Environment at the University of Oxford. He was Chief Scientific Adviser to the UK Government from 2000 to 2007