Fiona Harvey Up the Amazon without a reference

As we reported earlier, a claim that the IPCC was wrong on the effects of rainfall on the Amazon has been retracted.

What happened was, in brief, this: in its landmark 2007 report on climate science, the Intergovernmental Panel on Climate Change said that an estimated 40 per cent of the Amazon forest could be at risk from the sorts of reductions in rainfall expected from climate change.

Unfortunately, the source for this finding in the IPCC was not properly given. It was confused with a separate claim, based on a Nature paper, that was mainly about other factors that destroy the Amazon, such as logging, ranching and forest fire.

This confusion in the sourcing allowed climate change sceptics to claim that this was another example of the IPCC making things up.

It wasn’t. In fact, the 40 per cent finding had a highly credible source: the Amazon Environmental Research Institute (IPAM).

But the sceptics either did not know this, or ignored it.

Now, the spotlight has been thrown on this debacle once more because the UK’s press watchdog, the Press Complaints Commission, has ruled in favour of a scientist, Simon Lewis, who was misquoted in the report on the Amazonian claim run by the Sunday Times in January this year.

Dr Lewis told Energy Source he had been trying to point out that the Amazonian finding was correct, but should have been attributed to two separate sources.

So now it is clear that the original finding was correct. Some sceptics, however, have been scoffing still, saying that the science behind the finding was out of date and that the 2005 droughts in the Amazon showed that the rainforest was resilient to a lack of rainfall.

But Dr Lewis pointed out to us that he was co-author of another recent Science paper that backed up the original finding, by showing that the Amazon could under conditions of reduced rainfall – and even in the case of a reduction in rainfall that is smaller than the reductions the IPCC is forecasting – be extremely vulnerable.

The debacle shows how in the heat of the “Climategate” affair, claims were made about the IPCC’s findings and practices that have not all been borne out. The IPCC admits to one error, of claiming that the Himalayan glaciers would melt by 2035. But the handful of other complaints that have been brought – the Amazonian finding, which has been much discussed all over the blogosphere; a finding that parts of North Africa could see crop yields decline drastically (which the IPCC concedes was “poorly worded”); complaints concerning its use of “grey literature” that had not been peer-reviewed – it stands over.

An inquiry convened by the IPCC into the claims is not expected to report until the autumn.

That the IPCC has been vindicated in the case of this alleged error is unlikely to make much impression on jubilant sceptics. Nor is the story likely to gain the prominence that the original allegation did. Unfortunately, mud – Amazonian mud, in this case – sticks.