November 11, 2013

expert reaction to corrections to IPCC’s AR5 summary for policymakers

The IPCC revised estimates of historical greenhouse gas emissions from their AR5 summary for policymakers, but said the errors did not affect overall conclusions.

Professor Brian Hoskins, Grantham Institute for Climate Change, Imperial College London, said:

“These corrections are minor adjustments to historical greenhouse gas emissions (Section B) and to the cumulative emissions consistent with achieving a 2 degree warming target with different levels of probability (Section E).  These minor corrections do not affect any of the conclusions drawn in the Summary for Policy Makers. ” 

Professor Myles Allen, Head of the Climate Dynamics Group, University of Oxford, said:

“These errors are all rather small adjustments to numbers, mostly arising from needing to include 2011 emissions in the cumulative totals, and were spotted almost immediately by the IPCC authors themselves. This just shows that science is self-correcting and that those best placed to spot errors and publish them are those closest to the science.”

Andrew Watkinson, Professor of Environmental Sciences, University of East Anglia (UEA), said:

“I do not think the mistakes are significant in terms of the messages and conclusions, although they are mostly revisions upwards. For clarity the errata should have given the incorrect figures as well as the corrected figures and also related them back to the Technical Summary and individual chapter.

“They are clearly not typos as you can trace the various numbers back through the Technical Summary to the Chapter Report, which is at least the case in terms of the errors in Section B5.

“The errors in this case seem to relate primarily to Table 6.1 although the the original figure of 545 only appears in the text. It is then difficult to determine where the original error comes from as in the case of the incorrect 365, the reference for that is (Boden et al., 2011), and updated to 2011 using BP energy statistics. Was an error made in these calculations, which has now been corrected?

“Given a work of this complexity, it is not surprising, given the best efforts, that some errors creep through. It is a credit to the transparency of the system that they have been corrected, even at this late stage.”