Alleged IPCC Draft Report Leaks

The Australian newspaper reports on a leaked draft copy of the Intergovernmental Panel on Climate Change's (IPCC) upcoming report, scheduled to be released by 2007 [more]. The IPCC represents the scientific consensus of thousands of climate experts. Compared to IPCC's most recent 2001 report, predicted temperature and sea level rises have a smaller band of uncertainty if CO2 doubles. These “climate sensitivity” predictions are that average global temperatures will increase by about 3 degrees Celsius (5.4 F), with a range of possibilities from 2 C to 4.5 C (in 2001 the range given was 1.4 C to 5.8 C). Sea levels are now predicted to rise between 14 cm and 43 cm (5.5 to 17 inches, (previously range set at none to a meter). Note the newspaper article confuses climate sensitivity and predictions for warming in 2100, and spins the story in a decidely skeptical manner. There is no good news to be found in these findings, if indeed this is the true draft report, as efforts to reduce carbon emissions lag and if trends continue we are almost certainly going to double carbon emission levels before the end of the century, leading to global heating well above the 2 C warming generally acknowledged as “dangerous”.

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7 Responses

  1. Almuth Ernsting says:

    Although I have not read the leaked IPCC report, I have been following all the information on closely and therefore have some idea of what will be in it. My understanding is that the 2-4.5 degrees C warming is NOT the IPCC's prediction for this century. It is the most likely total warming if CO2 atmospheric concentrations reach 550 ppm. This is called 'climate sensitivity'. Even for this 2-4.5 degrees C is only the 'best bet', whilst uncertainty (including at the top end) now appears to be far greater than it did in the last 2001 report (that's because of uncertainty over positive cloud feedbacks which nobody can yet predict). Worst of all, the business as usual scenario will see CO2 levels far above 550 ppm. That will, of course, mean more warming. The Hadley Centre, UK, speak of possible 8 degrees C warming by 2100 (with carbon cycle feedbacks). As Glen says rightly: No crumbs of hope, but a strong call on all of us to act now!

  2. John C. Wilson says:

    I'll try again. A 14cm rise in sea level over the next 94 years would be about 1.5mm per year. Current estimates for sea level rise happening right now are 2.8 to 3.4 mm per year. So this alleged IPCC report has sea level rise slowing down. Not a credible report. Or possibly just a confused report, reporters are always very weak on any story that uses numbers

  3. Pegasus says:

    While we wait for the IPCC report one thing is clear. That no matter the content there will not be enough definitive proof to convince either side in this debate. And while “the business as usual scenario” is certainly a dangerous one worse yet is the lack of consensus and apathy. Perhaps we should all focus less on climate change and more on changing perceptions.

  4. Catherine Jansen says:

    Regarding Almuth Ernsting's comment, which is a very important one… Just wanted to reiterate that the new figures represent CO2 doubling sensitivity. The old range was 1.5 to 4 degrees C. The new range is 2 to 4 degrees C, slightly narrower. In other words, when CO2 reaches double preindustrial levels, at 560 ppm, we can expect an increase of 2 to 4 degrees C over preindustrial mean global temps.
    This is different from the 1.4 to 5.8 degrees C temperature increase prediction for 2100, since that is based on different emissions scenarios, with greatly varying C02 atmospheric levels.
    For further information, the post at is indeed an excellent place to go.

  5. Glen Barry says:

    I sure do appreciate the clarification that the data is for climate sensitivity of doubling carbon dioxide levels and not predictions. Scientific American who also picked up the story has a good response at . I have updated the item to be more clear.

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