IPCC Warns of Dire Climate Consequences

On November 17, 2007 the Intergovernmental Panel on Climate Change (IPCC) released its fourth “Synthesis Report” along with a “Summary for Policymakers.” The latest report integrates the findings of reports released earlier in 2007 by each of the three IPCC working groups, which dealt, respectively, with the underlying science of climate change, the likely impacts, and mitigation options.

Perhaps emboldened by the 2007 Nobel Peace Prize, which IPCC shared with Al Gore, scientists reportedly resisted efforts by major carbon-emitting countries to water down the conclusions in the report. Compared with previous IPCC reports, the Fourth Report is stronger in its warnings and written in a manner that is more accessible to non-scientists among politicians and the general public. It outlines six possible scenarios in terms of greenhouse gas emissions, the resulting atmospheric warming, and the likely impacts on human and ecological systems. Even the best-case scenario is daunting.

Among the mitigation options, this report summarizes the Working Group III conclusions that the building sector offers the greatest potential for cost-effective carbon emission reductions. Among options costing less than $20 per metric ton of avoided carbon, buildings provide at least three times the potential of any other sector, according to the report. Policymakers will rely heavily on this report when they meet in December in Bali, Indonesia, to begin work on the sequel to the 1997 Kyoto Procotol and the 2001 Marrakesh Accords that detailed the Protocol’s implementation.