It is becoming increasingly common for ecosystem services - services provided by the natural environment that benefit people - to have a financial value attached.  The idea is that it can help with management decisions relating to the environment.  For example, if we can say how much something is worth, then we can work how just how much to charge organizations like say BP when damage to the environment occurs through say an oil spill.  One of the main problems with valuing ecosystem services lies in how they are valued, because there is no one set procedure for doing so. What you can end up with is a value that only reflects what you chose to place a value on.  This is further complicated by unknown ecosystem services, and links between ecosystems which are yet to be fully understood. A few weeks ago the UK’s National Ecosystem Assessment valued the 127 English 'marine conservation zones' suggested by Government Science Advisory Panel between at £1.87 billion and £3.39 billion to the economy each year - just from divers and anglers which includes links to the NEA report).  Dr Tom Webb of the University of Sheffield in the UK has been casting an eye over this report and according to his calculations something doesn't quite add up.

Tom has written an excellent piece on where he feels things have gone awry enough to start of his "bullshit klaxon" that was "loud enough to knock me off my chair".  Here's an example of where Tom thinks the calculations are wrong.  The NEA suggested that a marine conservation zone known as 'Offshore Brighton' would receive between 26,000 to 44,000 diver visits a year (70 to 120 per day).  Tom notes that the dive site requires boat access, and that ten dive boats would need to be in operation every single day of the year for that to happen.  Does it?  Not a cat in hells chance says Tom.

Tom points out that some of the report was done very well, and he does a good job at giving an example at how ecosystem valuations can be misleading, and how they can be improved to be more representative of the true value.

The lead author of the NEA report has commented on the blog too - very much worth a read - there's a nice discussion going on there.