Wednesday, January 24, 2007

Stern slams Stern report

Above - estimated fossil-fuel black carbon emissions since 1875, in gigatons (billions of tons) per year.

In October last year, the UK Treasury sponsored Stern report on climate change was published together with a massive publicity campaign. The report made the following conclusions;

  • If nothing is done to reduce carbon emissions then the level of carbon in the atmosphere will climb to 550ppm by 2035 (currently 430ppm), causing temperatures to rise by 2C

  • By the end of the century, the stock of greenhouse gases could more than treble, leading to a rise of 5C in average temperatures.

  • Flood risk from melting glaciers would then threaten one sixth of the world's population and up to 40% of species would face extinction.

  • Temperature change of 5C will cause global output to fall by up to 20%, greater then the Great Depression

  • However, if emissions are contained at 550ppm, the fall in GDP will be just 1% of output

However, a fascinating interview in this week's Spectator (subscription only) reveals a very different side to the story. It appears that the UN Intergovernmental Panel on Climate Change (IPCC), the world authority on whose work the Stern report was itself based, is preparing its own review on the economics of climate change due for release later this year.

It calculates that the 550ppm target would cost up to 5% of economic output, five times the figure Stern suggests. The IPCC declares it has found a

"high level of agreement and much evidence"

So how sure is Stern that his claims add up?

"We don't have sufficiently detailed knowledge to simply add this up. Anyone who places too much faith in one computer model is deluding themselves."

Those 'deluded' souls include

  • European Commission
  • The UK business lobby, the CBI
  • Greenpeace
  • The Carbon Trust
  • Prime Minister, Tony Blair ("the most important report on the future ever published by this government". )
  • Future UK PM, Gordon Brown
  • The Trades Union Congress

Good to see that UK policy is being decided on 'insufficient knowledge' and by 'delusionals'.

Update 29/1; A BBC report for Radio 4 pours more cold water on Stern and his suspect economics. Prof Richard Tol, professor at both Hamburg and Carnegie Mellon Universities, and one of the world's leading environmental economists (i.e not some eco-sceptic loon).

"If a student of mine were to hand in this report as a Masters thesis, perhaps if I were in a good mood I would give him a 'D' for diligence; but more likely I would give him an 'F' for fail"
He continues in a similar vien,

"There is a whole range of very basic economics mistakes that somebody who claims to be a Professor of Economics simply should not make"

Many economists are also sceptical about the figures Stern uses to estimate the costs of reducing our greenhouse gas emissions. The review suggests this will cost only 1% of GDP but according to Yale University Economist Robert Mendelsohn, this is far too optimistic and the figure could easily be much higher.

"One of the depressing things about the greenhouse gas problem is that the cost of eliminating [it] is quite high. We will actually have to sacrifice a great deal to cut emissions dramatically,"

Translation - the report is unmitigated bollocks and at 670 pages, is a waste of a good copse.