Tuesday, February 09, 2010

Finding the source of the Amazongate

Thanks to EarthObservatory.
Right, now, we are going to have to take this steady.

I blogged that Amazongate, another case of the IPCC not checking its sources, is another AGW skeptick damp squib.

I get a comment from Richard North, (not Richard D North) who says that it is not that simple.
I respect Richard, because were allies in the struggle for vaccination in the 2001 FMD scandal.

Lets try to make it simple, using numbers. 

  1. The Sunday Times Publishes a piece originally entitled
    UN climate panel shamed by bogus rainforest claim” saying that the IPCC referred to an unsubstantiated piece from the WWF document entitled Global Review of Forest Fires:
  2. WWF replies that it was substantiated
  3. Richard North says no it wasn't

    So let's go back to the source.
  4. IPCC published the following statement:
    Up to 40%of the Amazonian forests could react drastically to even a slight reduction in precipitation; this means that the tropical vegetation, hydrology and climate system in South America could change very rapidly to another steady state, not necessarily producing gradual changes between the current and the future situation (Rowell and Moore, 2000).
  5. We follow the reference to Rowell, A. and P.F. Moore, 2000: Global Review of Forest Fires. WWF/IUCN, Gland, Switzerland, 66 pp. where we read:
    Up to 40% of the Brazilian forest is extremely sensitive to small reductions in the amount of rainfall. In the 1998 dry season, some 270,000 sq. km of forest became vulnerable to fire, due to completely depleted plant-available water stored in the upper five metres of soil. A further 360,000 sq. km of forest had only 250 mm of plant-available soil water left.
    This is referenced to D. C. Nepstad, et al: Large - scale Impoverishment of Amazonian Forests by Logging and Fire, Nature, 1999, Vo l 398, 8 April, pp505, on line here.
  6. But we cannot find that exact quote in the Nepstad paper. We do however find this:
    we find that surface fires burn additional large areas of standing forest, the destruction of which is normally not documented. Forest impoverishment due to such fies may increase dramatically when severe droughts provoke forest leaf-shedding and greater flammability; our regional water-balance model indicates that an estimated 270,000 sq km of forest became vulnerable to fire in the 1998 dry season.

    and this:
    Because of the severe drought of 1997 and 1998, we calculate that approximately 270,000 km2 of Amazonian forest had completely depleted plant-available water stored in the upper five metres of soil by the end of the 1998 dry season.
  7. I hope you are still with me. Hello?

  8. So, Richard North is rightish in asserting that the "specific assertion" is not substantiated, but the WWF is rightish in that references do exist to support the assertion that large areas of Amazon are vulnerable to fire. Which is the main point, when all is said and done.
  9. Lessons learned: always check your sources, boring as that might be, especially if you work with the IPCC, because otherwise the bogeymen AGW skeptics will get you.
PS my guess is that Moore and Rowell copied their quote from an earlier draft of the paper, and the copied passage was subsequently changed.

PPS I hope that is helpful. I need to go and have a little lie down now.

PPPS The conservatives used to criticise the habit of sticking -gate on the end of anything that was controversial, now they are doing it themselves. How times change.