In case you hadn’t noticed, the IPCC released its AR4 Synthesis Report, Summary for Policymakers on Saturday.

‘Today the world’s scientists have spoken clearly and with one voice,’ said United Nations Secretary General Ban Ki-moon.

The BBC reported the event on Friday (R4 news 18:00), before the report was published…

HARRABIN: They’re haggard with lack of sleep, but beaming that they’ve reached an agreement on an unequivocal message to politicians that climate change is real, dangerous, but manageable if steps are taken now. The results are compromised as usual, some wanted the final wording softer, others more strident still, but I’m told the final document when it’s published tomorrow will be impossible to ignore. It’ll say that we can see climate change happening already, sometimes, like in the Arctic, much faster than scientists predicted previously. We’re likely to have more droughts, floods, oppressive heatwaves and species extinctions, it’ll say, and some changes will be irreversible. That last phrase is so strong that some countries wanted it left out, but according to Steffan Zinger of WWF, they were voted down. 

ZINGER: The word irreversible for instance was strongly debated and strongly questioned by certain governments which are on the other side of the Atlantic. But they in the end gave in and accepted that climate change will have irreversible consequences.

So that’s how the ‘science’ that is supposed to inform the political process is achieved… Everybody stays up late, and argues until somebody ‘gives in’, or is ‘voted down’. Some kind of ‘speaking clearly and with one voice’.

Despite the headlines and column inches, there is virtually nothing new in this report. It’s a rehash of the three reports published earlier this year by the IPCC. All that is new in the report itself (and which most news outlets chose to lead with) is the word ‘irreversible’. Writing on the BBC website, for example, environment correspondent Richard Black tells us that ‘The IPCC states that climate change is ‘unequivocal’ and may bring ‘abrupt and irreversible’ impacts’. But the only mention of these words in the IPCC report are in the section ‘Anthropogenic warming could lead to some impacts that are abrupt or irreversible, depending upon the rate and magnitude of the climate change’, which reveals a far less frightening and urgent picture than such accounts suggests:

Partial loss of ice sheets on polar land could imply metres of sea level rise, major changes in coastlines and inundation of low-lying areas, with greatest effects in river deltas and low-lying islands. Such changes are projected to occur over millennial time scales, but more rapid sea level rise on century time scales cannot be excluded. {3.4} 

Does that mean immediate sea-level rise can’t be ruled in? ‘We don’t know’ would have sufficed. Similarly…

Climate change is likely to lead to some irreversible impacts. There is medium confidence that approximately 20-30% of species assessed so far are likely to be at increased risk if increases in global average warming exceed 1.5-2.5oC (relative to 1980-1999). As global average temperature increase exceeds about 3.5oC, model projections suggest significant extinctions (40-70% of species assessed) around the globe. 

It shouldn’t come as a surprise to anybody that extinction is an irreversible process. The clue is in the word “extinct”. And anyway: likely… some… medium confidence… approximately… 20-30% of species assessed so far… likely… increased risk… if… Of how many ‘assessed species’, exactly?

As for the ‘abrupt’ bit (which isn’t new, in that it was in the Working Group II report published back in April), all we get is

Based on current model simulations, the meridional overturning circulation (MOC) of the Atlantic Ocean will very likely slow down during the 21st century; nevertheless temperatures over the Atlantic and Europe are projected to increase. The MOC is very unlikely to undergo a large abrupt transition during the 21st century. Longer-term MOC changes cannot be assessed with confidence. Impacts of large-scale and persistent changes in the MOC are likely to include changes in marine ecosystem productivity, fisheries, ocean CO2 uptake, oceanic oxygen concentrations and terrestrial vegetation. Changes in terrestrial and ocean CO2 uptake may feed back on the climate system. 

Contrasting the report with statements in the press reveals very different pictures. Over the weekend, BBC Radio 4 was ending its news items on the report with: ‘The mainstream message from the IPCC is that it’s not too late – if we act now.’ According to Black’s article on BBC online: ‘The panel’s scientists say the reversal needs to come within a decade or so if the worst effects of global warming are to be avoided.’ Trouble is, the report doesn’t actually say that. Anywhere. At all. Whatsoever.

So what is going on here? It is true that Dr Pachauri said in the press conference that CO2 emissions need to peak and start declining by 2015. But Pachauri is not the IPCC. And as we’ve pointed out recently, his statements on this issue do not reflect the IPCC position. Meanwhile, journalists are happy to confound ‘the consensus’ with ‘what Pachauri reckons’ because that way they can say that ‘things are worse than ever before’.

The only differences between this report (and the press coverage of it) and previous ones concern the language, not the science. That language is getting more abrupt, and the problem is becoming irreversible. And our models predict it to get worse than previously expected.