The Fourth Assessment Report (AR4) of Working Group II (WG2) of the Intergovernmental Panel on Climate Change (IPCC) has been discussed extensively in recent months. A number of errors were discovered. Few documents are without fault. What is surprising, however, is that the IPCC has denied obvious mistakes; and that the errors all point towards alarmism about the impacts of climate change.
The WG3 report did not attract the same scrutiny. This could create the impression that WG3 wrote a sound report. That impression would be false. Just as WG2 appears to have systematically overstated the negative impacts of climate change, WG3 appears to have systematically understated the negative impacts of greenhouse gas emission reduction.