Michael Oppenheimer, a climate science and policy expert at Princeton University and a lead chapter author for SREX, disagreed. "While some additional literature has been published since our deadline, I don't believe it changes the picture materially," he told InsideClimate News.
Did the IPCC address any other factors affecting extreme weather besides human-caused greenhouse gases?
Yes, but its focus was on man-made warming. The IPCC acknowledged that "climate extremes, exposure, and vulnerability are influenced by a wide range of factors, including anthropogenic climate change, natural climate variability, and socioeconomic development."
In the future, natural variability "will be an important factor" in shaping extremes, it said, in addition to man-made heat-trapping gases, though it didn't given any probabilities or percentages for natural variability.
What are the implications for climate change action?
The report comes just as representatives of 194 nations gear up for the Nov. 28-Dec. 9 climate negotiations in Durban, South Africa. SREX's co-chairs and IPCC senior members said during a Friday press conference that they aren't sure what impact their work will have on moving climate policies forward, in global talks and in the U.S. Congress.
However, they are hopeful SREX can move the ball on adaptation.
The report includes strategies to prepare for climate-related disasters, like building flood barriers, investing in early warning systems, improving water supply and educating communities being affected by extremes. Some forms of adaptation, like certain farming techniques, can also act as mitigation by trapping carbon in soils.
Many climate advocates, as well as global insurers hard hit by weather disasters and business groups, called the report yet another wake-up call to world leaders to take the warming threat seriously. Big investors in particular have been looking for governments to give them clear and consistent signals they they're transitioning the global economy from carbon intensive to low carbon.
How have the skeptics responded?
Several skeptics who question whether global warming is really happening criticized the IPCC's use of words like "likely" to express the probability of its many predictions, as well as the panel's acknowledgement that natural climate variability plays a small role in these extremes. They argue these descriptions are wishy-washy and were introduced only to let the IPCC off the hook, following a controversy last year over an incorrect claim about the imminent melting of the Himalayan glaciers.
Expressing this view, Joanne Codling, a popular Australian climate skeptic and scientist who calls herself Jo Nova, criticized the IPCC for this "multipurpose prediction." It means that "in the future, if it's colder, they're right; if it's warmer, they're right; and they have it covered for more or less storms, floods, droughts, blizzards and frost too," she said.