IPCC chief: even peaking emissions at 2015 will trigger rise of up to 2.4°C
19 November 2007 7:44am
The head of the UN has called for 'sweeping, concerted action now', as the head of the Intergovernmental Panel on Climate Change warns even if greenhouse gas emissions peaked by 2015, temperatures would increase by up to 2.4°C and sea levels would eventually rise up to 1.4 metres – without factoring in melting ice.
Speaking at Saturday's launch in Spain of the IPCC's 23-page synthesis report, UN Secretary-General Ban Ki-moon urged all countries, including the US and China, to do more.
The key synthesis report conclusions are set out in a 17-slide presentation by Dr R.K. Pachauri, head of the IPCC.
"Today the worlds scientists have spoken clearly and with one voice," the UN Secretary-General said at the launch of the synthesis report. "In Bali, I expect the world's policy makers to do the same."
The Bali conference should initiate negotiations for a comprehensive climate change agreement "that all nations can embrace" and should agree to concluding these negotiations by the end of 2009, he said. (Hear Ban Ki-moon below)
"The synthesis report has answered many of our policy questions," he said. "Now, starting in Bali, it is up to the rest of us to start transforming those answers into action."
"We cannot afford to leave Bali without such a breakthrough," he said. "Global, sweeping, concerted action is needed now there is no time to waste."
The Secretary-General said he was considering holding another UN General Assembly summit on climate change "right after" the Bali meeting to maintain the momentum.
The synthesis report contains "one overarching message for all of us", he said. "The threat of climate change is real and there are concrete and affordable ways to deal with it."
"As this report makes clear, concerted and sustained action now, can still avoid some of the most catastrophic scenarios," he said.
Ban Ki-moon said he had "high expectations of all countries", including the U.S. and China. "I look forward to seeing the U.S. and China playing a more constructive role in the coming negotiations on future international cooperation on climate change starting from the Bali conference," he said.
"Both countries I think can and should lead, each in its own way."
Key findings distilled
The synthesis report distils key findings of the three working group reports released over the course of the year (the Working Group I
report on the physical science, the Working Group II
report on impacts, adaptation and vulnerability and the Working Group III
report on mitigation).
It completes the IPCC 4th assessment report process, which has involved about 450 lead authors from more than 130 countries and involved about 2,500 scientific expert reviewers and 800 contributing authors.
Member governments of the IPCC have also endorsed the findings.
Sea-level rise
IPCC chief Pachauri said at the report launch press conference that "an important finding" set out in the synthesis report was that stabilising emissions at 350ppm-400ppm CO
2 (equivalent to 445ppm-490ppm CO
2e) would imply temperature rises of 2°C to 2.4°C, though this level of increase might not be reached within the 21st century.
Considering only the associated sea level rise due to thermal expansion, this would result over many centuries in a rise of between 0.4 to 1.4 metres.
"This is an extremely serious finding," he said.
As well, the partial loss if ice sheets could imply "metres of sea level rise", Pachauri noted.
(Hear Pachauri's first audio clip below. Pachauri refers in the clip to slide 13 of his presentation) Pachauri said the IPCC Working Group III report had made it clear that if the world wants to stabilise atmospheric levels of greenhouse gases at 445ppm CO
2e or just above "we have time up to 2015 to let emissions increase. But after that, at the year 2015, they will have to peak and start declining thereafter."
"That raises the issue of burden-sharing," Pachauri said. "Who's going to do how much. And I don’t see a resolution to that challenge unless every country in the world gets committed on the basis of some set of principles and criteria of fairness and equity – and I would say ethics – by which we can reach the goal of much lower emissions."
(Hear Pachauri's second audio clip below) (
The synthesis report notes atmospheric CO2 concentrations were 379ppm in 2005. The best estimate of 2005 CO2e concentrations for all long-lived greenhouse gases is about 455ppm, but taking into account the net effect of all relevant anthropogenic agents (for example the cooling effect of aerosols in the atmosphere) it is 375ppmCO2e, it says. Pachauri's reference to 445ppm is a reference to CO2e taking account of all long-lived greenhouse gases as well as aerosols. )
What the synthesis report says
"Warming of the climate system is unequivocal," the synthesis report says. "Many natural systems are being affected by regional climate changes, particularly temperature increases," it says.
Findings outlined in the report and Pachauri's presentation include:
- global greenhouse gas emissions from human activities increased 70% between 1970 and 2004;
- most of the observed increase in globally-averaged temperatures since the mid-20th century is "very likely" due to the increase in greenhouse gas concentrations;
- globally, the area affected by drought has likely increased since the 1970s;
- the rate of global average sea level rise has risen from 1.8mm a year to 3.1mm a year from 1961 to 1993;
- projected sea-level rise at the end of the 21st century will be 18-59cm, but partial loss of ice sheets on ice polar land could imply metres of sea level rise resulting in major changes in coastlines and inundation of low-lying areas with great effects in river deltas and low-lying islands; and
- about 20-30% of species assessed so far are likely to be at increased risk of extinction.
The impacts would be felt differently in different regions. (
Click to see list of impacts by region extracted from summary report)
The cost of solutions
Pachauri said a wide variety of policies and instruments could help the world rein in greenhouse gas emissions and adapt to climate change. These include "a portfolio of technologies" and properly pricing carbon, he said.
"If we want action then clearly there has to be a price attached to carbon which will move us towards a low-carbon economy." (
Click to see table of key mitigation measures by sector extracted from summary report)
A graph included in the
report (page 16) and Pachauri's
presentation (slide 10) shows the significant difference in total global abatement levels associated with varying carbon prices.
Pachauri said the cost of action would depend on the stringency of the stabilisation target.
Aiming for stabilisation at levels between 445ppm CO
2e and 710 CO
2e would, in 2050, result in a global average macro-economic impact in 2050 ranging from a 5.5% decrease in global GDP to a 1% increase, the report says.
This corresponds to slowing average annual global GDP growth by less than 0.12%.
Summary For Policymakers of the Synthesis Report of the IPCC Fourth Assessment Report (IPCC, November 17, 2007) Presentation: 27th Session of the Intergovernmental Panel on Climate Change (Presented by Dr R.K. Pachauri under the imprimatur of IPCC, WMO and UNEP, November 17, 2007) Click here for audio and webcast versions of the press conference involving Ban Ki-moon, Dr Pachauri, UNEP chief Achim Steiner and head of the WMO Michel Jarraud (the webcast version also includes a separate address by Ban Ki-Moon, the audio version includes only the press conference)
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