The IPCC Messed Up over 'Amazongate' - the Threat to the Amazon is Far Worse

Challenging climate sceptics is good sport but we're in danger of forgetting the deadly serious matter at hand

Well this becomes more entertaining by the moment. Those who staked
so much on the "Amazongate" story, only to see it turn round and bite
them, are now digging a hole so deep that they will soon be able to
witness a possible climate change scenario at first hand, as they emerge, shovels in hand, in the middle of the Great Victoria Desert.

Here's
the story so far. In January the rightwing blogger Richard North
claimed that the Intergovernmental Panel on Climate Change had "grossly
exaggerated the effects of global warming on the Amazon rain forest".
In 2007 the Panel had claimed that "up to 40% of the Amazonian forests
could react drastically to even a slight reduction in precipitation".
Reduced rainfall could rapidly destroy the forests, which would be
replaced with ecosystems "such as tropical savannahs."

North asserted that this "seems to be a complete fabrication", though see this update too.
His story was picked up by hundreds of other climate change deniers,
some of whom went so far as to claim that it destroyed global warming
theory. It was also run by the Sunday Times, which headlined its report
"UN climate panel shamed by bogus rainforest claim".

Two
weeks ago the Sunday Times published a complete retraction. That, you
might think, would be the end of the matter. How wrong you would be.
Far from accepting that they had made a mistake, the promoters of this
story now seem determined to compound it. On Sunday our old friend Christopher Booker asserted
that "an exhaustive trawl through all the scientific literature on this
subject by my colleague Dr Richard North (who was responsible for
uncovering "Amazongate" in the first place), has been unable to find a
single study which confirms the specific claim made by the IPCC's 2007
report ... all observed evidence indicates that the forest is much more
resilient to climate fluctuations than the alarmists would have us
believe."

There is no doubt that the IPCC made a mistake.
Sourcing its information on the Amazon to a report by the green group
WWF rather than the substantial peer-reviewed literature on the
subject, was a bizarre and silly thing to do. It is also an issue of
such mind-numbing triviality, in view of the fact that the IPCC's 2007
reports extend to several thousand pages and contain tens of thousands
of references, that I feel I should apologise for taking up more of
your time in pursuing it. But the climate change deniers have made such
a big deal of it that it cannot be ignored.

It is also
true that nowhere in the peer-reviewed literature is there a specific
statement that "up to 40% of the Amazonian forests could react
drastically to even a slight reduction in precipitation". This figure
was taken from the WWF report and it shouldn't have been.

But
far from "grossly exaggerating" the state of the science in 2007, as
North claimed, the IPCC - because it referenced the WWF report, not the
peer-reviewed literature - grossly understated it. The two foremost
peer-reviewed papers on the subject at the time of the 2007 report were
both published in Theoretical and Applied Climatology. The references
are below. They are cited throughout the literature on Amazon dieback.

What do they tell us? That the projection in the IPCC's report falls far, far short of the predicted impacts on the Amazon.

The
first paper, by Cox et al, predicts a drop in broadleaf tree cover from
approximately 80% of the Amazon region in 2000 to around 28% in 2100
(Figure 6). That is bad enough, involving far more than 40% of the
rainforest. But the forest, it says, will not be largely replaced by
savannah: "When the forest fraction begins to drop (from about 2040
onwards) C4 grasses initially expand to occupy some of the vacant
lands. However, the relentless warming and drying make conditions
unfavourable even for this plant functional type, and the Amazon box
ends as predominantly baresoil (area fraction >0.5) by 2100."

In
other words, the lushest region on earth is projected by this paper to
be mostly replaced by desert as a result of global warming (and the
consequent reduction in rainfall) this century. I hope I don't have to
explain the consequences for biodiversity, the people of the Amazon or
climate feedbacks, as the carbon the trees and soil contain is oxidised
and released to the atmosphere.

So what does the second
paper say? Betts et al go even further. In their model runs: "By the
end of the 21st Century, the mean broadleaf tree coverage of Amazonia
has reduced from over 80% to less than 10%."

They are
slightly more sanguine about the savannah/desert balance. "In
approximately half of this area, the trees have been replaced by C4
grass leading to a savanna-like landscape. Elsewhere, even grasses
cannot be supported and the conditions become essentially desert-like."

Isn't that reassuring? It is worth noting that both these papers are referenced elsewhere in the IPCC's 2007 report.

They
are not alone. One of the runs in a 1999 paper by White, Cannell and
Friend, also published in a peer-reviewed journal (see below) shows
almost the entire Amazon basin as desert by the 2080s (Figure 2b(ii)).

Compare
these projections to Booker's claim that "all observed evidence
indicates that the forest is much more resilient to climate
fluctuations than the alarmists would have us believe."

So
now the promoters of the Amazongate story have three options. They can
persist in claiming that the IPCC was wrong, but this time on the
grounds that it underestimated the likely response of the Amazon to
climate change. But that would create more problems for them than it
solved. They could fall back on their age-old defence and claim that
it's all irrelevant, because the scientists' projections for how the
Amazon might respond to climate change are based on models. But that
would oblige them to suggest a better means of predicting future
events. Tealeaves? Entrails? Crystal balls? Or they could quietly slink
away before this doomed crusade causes them any more embarrassment, and
find something more useful to do.

Booker ends his piece by
maintaining that on "the only occasion" on which I had attempted to
expose the misinformation he peddles, I got it wrong and had to
apologise to my readers. Yes, I did get one of my claims wrong and I said so as soon as I discovered it. This is where Christopher and I differ: I admit my mistakes, he does not.

But
I'm fascinated by his assertion that this was "the only occasion" on
which I pulled him up. Either he has a very short memory or a very
selective one. To prompt some glimmer of recognition, here are some of
the other occasions on which I have pointed out his mistakes:

In 2007 I showed that Booker and North had used cherry-picking to support their claim that speed cameras had impeded the decline of deaths
on the roads. They had ignored the latest evidence (which flatly
contradicted their claims), misquoted a House of Commons report and
changed the date of an article of mine, which had the effect of making
their narrative more convincing.

In 2008, I showed how
Booker had misquoted scientific papers, engaged in cherry-picking and
relied on the word of a man convicted under the Trade Descriptions Act
for making false claims about his qualifications to support his
contention that white asbestos cement "poses no measurable risk to
health".

I also drew attention to my favourite Bookerism:
his observation, in February 2008, that "Arctic ice isn't vanishing
after all." The "warmists", he pointed out, had made much of the fact
that in September 2007 northern hemisphere sea ice cover had shrunk to
the lowest level ever recorded. But now it had bounced back, proving
how wrong they were. To reinforce this point, he helpfully published a
graph, showing that the ice had indeed expanded between September and
January. I pointed out that the Sunday Telegraph continued to employ a man who cannot tell the difference between summer and winter.

In 2009, I detailed six howling mistakes about climate change in just one of his columns. Last month I lambasted
him for falsely claiming that under EU rules you'll be able to bury
dead pets only after "pressure cooking them at 130 degrees centigrade
for half an hour".

I don't mean to spend my life
correcting Booker's mistakes, but the volume of misinformation he has
published is mindblowing, and someone has to call him to account. Other
journalists, perhaps wisely, don't bother.

All this is
good knockabout stuff. But we're in danger of forgetting that it
concerns a deadly serious matter: a change in the climatic conditions
which have made human civilisation and the current human population
possible, and, specifically, the degradation of the most wonderful and
beautiful of the world's ecosystems into desert and scrubby grassland.
It is hard to overstate the irresponsibility of those who misrepresent
the science in order to persuade people that no action needs to be
taken.

References:

PM Cox et al, 2004.
Amazonian forest dieback under climate-carbon cycle projections for the
21st century. Theoretical and Applied Climatology, 78, 137-156. DOI
10.1007/s00704-004-0049-4

RA Betts et al, 2004.
The role of ecosystem-atmosphere interactions in simulated Amazonian
precipitation decrease and forest dieback under global climate warming.
Theoretical and Applied Climatology, 78, 157-175. DOI
10.1007/s00704-004-0050-y

A White, MGR Cannell, AD Friend, 1999.
Climate change impacts on ecosystems and the terrestrial carbon sink: a
new assessment. Global Environmental Change, 9, S21-S30.