UK 'must plan' for warmer future

Reposted from: http://news.bbc.co.uk/1/hi/sci/tech/8107014.stm

By Richard Black Environment correspondent, BBC News

Some regions of the UK are likely to see more floods, especially in winter

The UK needs to plan now for a future that will be hotter and bring greater extremes of flood and drought, says Environment Secretary Hilary Benn.

Launching the UK Climate Projections 2009 report (UKCP09), Mr Benn told MPs that the UK climate will change even with a global deal on emissions.

By 2080, London will be between 2C and 6C hotter than it is now, he said.

Every part of the UK is likely to be wetter in winter and drier in summer, according to the projections.

Summer rainfall could decrease by about 20% in the south of England and in Yorkshire and Humberside by the middle of the century.

These projections show us the future we need to avoid, and the future we need to plan for Hilary Benn See projections for your region

Scotland and the north-west of England could see winter rainfall increase by a similar amount.

The government hopes UKCP09 will allow citizens, local authorities and businesses to plan for future decades.

It uses computer models of the world's climate to make projections of parameters such as temperature, rainfall and wind.

"Climate change is going to transform the way we live," said Mr Benn.

"These projections show us the future we need to avoid, and the future we need to plan for."

UK CLIMATE PROJECTIONS

"These projections show us the future we need to avoid, and the future we need to plan for."

UK CLIMATE PROJECTIONS

An increase of 16% in winter rainfall in the North West, increasing the amount of rain on the wettest days leading to higher flood risk

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Average summer rainfall could decrease by 22% in the already water-stressed southern England

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By the 2080s, average summer temperatures could be up to six degrees warmer in parts of southern England

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An effective global deal at December's UN climate talks in Copenhagen could keep the summer temperature rise in southern England to about 2C, the projections suggest.

But if greenhouse gas emissions rise quickly, that figure could be as high as 12C, Mr Benn said.

Probable futures

The UK Met Office, which led the scientific analysis, says UKCP09 is the "most comprehensive set of probabilistic climate projections at the regional scale compiled anywhere in the world".

FROM THE WORLD AT ONE More from The World At One

Scientists collated data from 400 variations of the climate computer model developed by the Hadley Centre, part of the Met Office.

Each variant has been checked to see how well it predicted the climate of past decades; and the numbers have been compared with projections of other computer models.

This allowed scientists to assign probabilities to various forecasts.

Using a range of online tools including a "weather generator", people will be able to enter their postcodes and see projections of how conditions are likely to change within 25 sq km grid squares at different points in the future.

But some climate scientists have reservations about trying to project the future on such a detailed scale.

"If your decisions depend on what's happening at these very fine scales of 25 km or even 5 km resolution then you probably shouldn't be making irreversible investment decisions now," commented Myles Allen of Oxford University, one of the UK's leading climate modellers.

Climate warnings' error margins

But the idea of the impact assessment has been well received by environment groups.

"It's great that the government has decided to put together such a scientifically robust analysis of the potential impacts of climate change in the UK," said Keith Allott, head of climate change at WWF-UK.

"But the picture it paints is an alarming one,"

"This research confirms that not only is climate change already having a serious impact in Britain, but that we are also locked into further impacts, and that these impacts will get much worse unless we act now to tackle the problem."

Mild UK

Campaigners say that the UK impacts are likely to be minor compared to other parts of the world.

Last month a report from the Global Humanitarian Forum, the think tank chaired by former UN secretary-general Kofi Annan, said the UK was among the 12 countries likely to be least affected by climate change.

"Life in parts of the UK will get harder, but it will get a great deal harder in countries already suffering the impact of climate change," said Alison Doig, senior climate policy expert with Christian Aid.

Will British crops go thirsty?

"Their plight will worsen dramatically unless the international community wakes up to the fact that a full-blown emergency is looming."

On Friday, the Environment Agency will release an assessment of how the changing climate will affect the risk of impacts such as flooding in England and Wales.

Commenting on the UKCP09 projections, Environment Agency chairman Chris Smith said:

"These new projections remind us starkly of the choices we face in ensuring a sustainable future for our fragile planet.

"A failure to cut greenhouse gas emissions will lead to a battle for survival for mankind and many other species across the globe by the end of this century; and we will feel the effects here in the UK too."

The agency is likely to recommend measures that would protect areas of the UK, and sectors of the economy, against climate impacts such as flooding.

With hundreds of miles of roads and railways running along embankments, scientists are studying the impact of climate change on these vital structures

Richard.Black-INTERNET@bbc.co.uk

Climate warnings' error margins

Reposted from: http://news.bbc.co.uk/1/hi/sci/tech/8106513.stm

ANALYSIS By Pallab Ghosh Science correspondent, BBC News

Ever more precise climate models require ever larger computing power

Projections by the UK's Climate Impact Programme released on Thursday come with strict caveats about how they should be used and their margin for error.

The Department for the Environment, Food and Rural Affairs (Defra) and the Met Office argue that, even though the projections are far from certain, they will be useful to help plan for climate change in the UK.

But others have warned that the uncertainties in the projections are too great to be of practical use

Defra has produced projections of climate change and consequent weather using advanced computer modelling techniques.

Up until now, most projections have been at a sub-continental level - giving information at a regional level in squares of 300km on a side.

Defra's projections are among the first in the world to give information at a local level - to the scale of large cities of 25km square and, in some cases, projecting weather patterns to a village scale of 5km square.

Planning for change

The UK's Climate Impacts Programme projections were explicitly designed to help local authority planners and businesses make investment decisions to adapt to the consequence of climate change.

If your decisions depend on what's happening at these very fine scales, you probably shouldn't be making irreversible investment decisions now Dr Myles Allen, Oxford University

But according to Dr Myles Allen of Oxford University, who was among those who carried out an independent review of the projections, said that they may not be reliable enough at this stage to make some of the most important policy decisions.

"If your decisions depend on what's happening at these very fine scales of 25 km or even 5 km resolution, then you probably shouldn't be making irreversible investment decisions now," he said.

The review, published on Thursday, says that the projections are "credible" but does raise concerns that the statistical techniques used are untested and have not been published in a peer-reviewed journal.

The last assessment by a committee set up in 2007 by the Intergovernmental Panel on Climate Change (IPCC) concluded that these kinds of so-called "probabilistic" projections could only be applied reliably on a global scale - of 1000km square.

"The IPCC explicitly stepped back from making probabilistic projections on this sort of scale," said Dr Allen.

"The method that's been used to produce this projection is a very specific one.

"It's not been used before for this climate change approach and we thought that it would be helpful to provide a much more conservative method, something the IPCC would have used in 2007 just to provide users with a context and something to compare with so that they can see which aspects of these projections are robust."

Local governments need to address potential floods

Defra has not accepted the recommendation to provide an an alternative set of projections by the independent review panel because officials felt that having two sets would be confusing.

Dr Leonard Smith of the London School of Economics' Grantham Institute says he cannot see how any planner could make decisions on probable climate outcomes that are so uncertain that they might change substantially in 20 years.

"It's very hard to find a rational way of using them," he said.

"If the numbers are used in a naive way, then you are very likely to design a power plant or reservoir that doesn't meet the needs of the population."

Too far?

Many in the scientific community were particularly astonished that Defra published projections at a scale of 5km square - which are even more uncertain than the 25km square projections.

Among them was Professor Sir David King who was involved in commissioning the projections when he was the government's chief scientific advisor.

"If you include a 5km scale in your predictions, you are probably pushing things beyond what is realistic. So I'm a little surprised that scientists were prepared to go that far.

"If I was in the decision-making position in government, I would not have made the decision to publish those figures."

But Sir David backs Defra's decision to publish the figures at a 25km scale, despite the current uncertainties.

"There is the issue of saying to the local village council and the local city councils that this is an issue that affects you. I think that the driver was the need to get a message across to the people who make key decisions," he said.

If the numbers are used in a naive way, then you are very likely to design a power plant or reservoir that doesn't meet the needs of the population Leonard Smith London School of Economics

"I believe we need the best we can get so that we can set in train a good adaptive process to protect the country from risk of flood whether from rivers or flash floods in cities or coastal floods."

That view was echoed by Professor Sir Brian Hoskins of the Grantham Institute in London, who chaired the independent review of the projections.

"[These projections] will help people make decisions about planning and designing structures now. That doesn't say that the guidance will be identical in three years' time.

"But for those making decisions now, I think this information and providing it is a good thing to do."

Sir Brian's independent review was completed in January and has been held back until the publication of the projections this morning; in fact, those involved with the review were required to sign non-disclosure agreements.

Sir David believes that officials at Defra may have been anxious to avoid fuelling an already heated debate among the climate modelling community.

"Scientific challenge is essential to the scientific process. Civil servants are very sensitive to scientists disagreeing in public, I would be much happier if everyone could be more mature.

"If we say it as it is, I think the public would get used to the way that scientists work."