Taken from BBC News website (http://www.bbc.co.uk/news/science-environment-13616543) by Richard Black, 2 June 2011
The UK's parks, lakes, forests andwildlife are worth billions of pounds to the economy, says a major report.
The health benefits of merely living close to a green space are worth up to£300 per person per year, it concludes.
The NationalEcosystem Assessment (NEA) says that for decades, the emphasis has been onproducing more food and other goods - but this has harmed other parts of naturethat generate hidden wealth.
Ministers who commissioned the NEA will use it to re-shape planningpolicy.
"The natural world is vital to our existence, providing us with essentialssuch as food, water and clean air - but also cultural and health benefits notalways fully appreciated because we get them for free," said EnvironmentSecretary Caroline Spelman.
"The UK NEA is a vital step forward in our ability to understand the truevalue of nature and how to sustain the benefits it gives us."
The economic benefits of nature are seen most clearly in food production,which depends on organisms such as soil microbes, earthworms and pollinatinginsects.
If their health declines - as is currently happening in the UK with bees -either farmers produce less food, or have to spend more to produce the sameamount.
Either way there is an economic impact; and on average, the costs are growingover time.
Degrading report
"About 30% of the key ecosystem services that we rely on are degrading.
"About 20% are getting better, however - our air quality has improved a lot -and what this report says is that we can do a lot better across the board," hetold BBC News.
The 1940s saw the beginning of a national drive to increase production offood and other products such as timber.
Although that was successful, the NEA finds there was aprice to pay - England, for example, has the smallest percentage of forest coveranywhere in Europe, while many fish stocks are below optimum levels.
The report says the problem arises largely because currently, only materialproducts such as food carry a pricetag in the market.
By calculating the value of less tangible factors such as clean air, cleanwater and natural flood defences, it hopes to rebalance the equation.
The Royal Society for the Protection of Birds (RSPB) welcomed theassessment.
"The traditional view of economic growth is based on chasing GDP, but in factwe will all end up richer and happier if we begin to take into account the truevalue of nature," said its conservation director, Martin Harper.
"Of course no-one can put a pounds and pence value on everything in nature -but equally we cannot ignore the importance of looking after it when we arestriving for economic growth."
The NEA seeks to include virtually every economic contribution from eighttypes of landscape, such as woodlands, coasts and urban areas.
It also provides some local flavours by looking at variations across theUK.
Some figures emerge with precision, such as the £430m that pollinatinginsects are calculated to be worth, or the £1.5bn pricetag on inland wetlands,valued so high because they help to produce clean water.
Other aspects of the evaluation are less precise because the costs andbenefits are harder to quantify, and may change over time.
Ian Bateman, an economist from the University of East Anglia who played aprincipal role in the analysis, said that putting a single price on natureoverall was not sensible.
"Without the environment, we're all dead - so the totalvalue is infinite," he said.
"What is important is the value of changes - of feasible, policy-relevantchanges - and those you can put numbers on."
The full 2,000-page report is stacked full of such numbers. The governmentintends to use some of them in its forthcoming Natural Environment White Paperand other initiatives that could reform urban and rural planning.
Professor Watson said this did not imply an end to development, but thatcosts and benefits of each proposed development could be assessed moreaccurately in advance.
"Urban green space, for example, is unbelievably important - if affects thevalue of houses, it affects our mental wellbeing.
"This report is saying 'this has got incredible value, so before you startconverting green space into building, think through what the economic value isof maintaining that green space' - or the blue space, the ponds and therivers."
On the global stage, several countries have previously evaluated the economicworth of specific factors such as forests or fisheries.
And two international studies - the MillenniumEcosystem Assessment (MEA) and TheEconomics of Ecosystems and Biodiversity (Teeb) - have given broader viewsof society's environmental trajectory, and the costs and benefits.
But the UK is the first nation to produce such a detailed assessment acrossthe piece.