Comparing what the IPCC and peer-reviewed science say about Amazonian forests
What the science says...
Select a level... | Basic | Intermediate | |||
The IPCC statement on Amazon rainforests was correct, and was incorrectly reported in some media. |
Climate Myth...
IPCC were wrong about Amazon rainforests
"The IPCC also made false predictions on the Amazon rain forests, referenced to a non peer-reviewed paper produced by an advocacy group working with the WWF. This time though, the claim made is not even supported by the report and seems to be a complete fabrication." (EU Referendum)
An article in a British newspaper claimed that the Intergovernmental Panel on Climate Change (IPCC) published wrong information about the Amazon Rainforest in their 2007 report. The issue centred on the statement that about 40% of the Amazon was susceptible to the effects of drought, or more specifically "slight reductions in rainfall".
The Amazon is the world's largest tropical rainforest, and due to its immense size, has a global effect on the Earth's climate. Despite being well adapted and resilient to wet and dry periods which occur throughout the year, the rainforest is vulnerable to extended periods of drought. Any major decline in the health of the Amazon rainforest is likely to impact the world climate.
The skeptic claims relate to section 13.4.1 of the IPCC Fourth Assessment Report (2007) which made the 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)
The reference is to a non-peer reviewed report prepared by the World Wide Fund for Nature (WWF) which itself cites an original peer reviewed study (Nepstad et al. 1999) as the basis for the claim. The citations in the WWF and IPCC reports are not complete, Nepstad et al. 1994, Nepstad et al. 1999 and Nepstad et al. 2004 support the claim that up to half the Amazon rainforest were severely affected by drought. Further studies, carried out since the 2007 IPCC report, reinforce the Amazon's susceptibility to long term reductions in rainfall .
The IPCC could have avoided confusion by simply citing the peer reviewed studies themselves, rather than the WWF report and perhaps "slight reduction" should have been better defined or qualified. Despite the error in citation, the statement made by the IPCC is factually correct. Maybe the last word should go to the lead author of the papers upon which the statements were based, Daniel Nepstad, who made a public press release to clear up the mainstream media confusion over the subject. Nepstad concludes:
"In sum, the IPCC statement on the Amazon was correct. The report that is cited in support of the IPCC statement (Rowell and Moore 2000) omitted some citations in support of the 40% value statement.
Last updated on 30 October 2010 by Rob Painting. View Archives
Zeph,
I love your analogy (from a decade ago). The double standard you mention seems quite irrational. Why must changing our course require such an asymmetric burden of proof (free of any miniscule imperfection), while those who argue not to alter course have no such burden? Well, those asking us to “change course” move to take away our status quo and make us do "something extra"... very inconvenient, right? All burden is on them.
Your analogy shows us: neither decision is “something extra”… both “changing course” (reacting to data) and “continuing course” (not reacting to data) are decisions. A worse inconvenience (loss of time / money / life) could be present in either action. Passengers don’t want to experience delay (or sinking!) unnecessarily. Ideally, the next step isn’t based on matching the prior step, but instead is guided by the best data, which becomes stronger over time.
To this end, the captain sends 100 wood specialists down to evaluate. Ninety-seven return saying the rotten wood is starting to leak, present innumerable impressive data sets demonstrating risk of accelerated leaking & sinking, and recommend repair. Ship owners, not wanting idle vessels, argue it isn’t absolutely proven that the ship would sink, and point to 3 of the 100 specialists who found some imperfections in the models. Owners influence the captain to push the boat further out to sea, and taut to passengers how much inconvenience they are preventing.
Of course, the specialists wanting to repair the ship aren’t causing the major inconvenience… the data (rotten wood) is doing this. It makes no sense to put the burden of proof asymmetrically on those wanting to repair the ship. After all, it seems some owners won’t be convinced until the ship is partially submerged, which of course then is too late.