Okay, the Intergovernmental Panel on Climate Change does not do so in as many words. But in addition to being more confident than ever (despite a 16-year pause in warming and the growing mismatch between model projections and observations) that most recent warming is man-made, they are also more confident nothing really bad is going to happen during the 21st Century.
The scariest parts of the “planetary emergency” narrative popularized by Al Gore and other pundits are Atlantic Ocean circulation shutdown (implausibly plunging Europe into a mini-ice age), ice sheet disintegration raising sea levels 20 feet, and runaway warming from melting frozen methane deposits.
As BishopHill and Judith Curry report on their separate blogs, IPCC now believes that in the 21st Century, Atlantic Ocean circulation collapse is “very unlikely,” ice sheet collapse is “exceptionally unlikely,” and catastrophic release of methane hydrates from melting permafrost is “very unlikely.” You can read it for yourself in Chapter 12 Table 12.4 of the IPCC’s forthcoming Fifth Assessment Report.
But these doomsday scenarios have always been way more fiction than science. For some time now, extreme weather has been the only card left in the climate alarm deck. Climate activists repeatedly assert that severe droughts, floods, and storms (Hurricane Sandy is their current poster child) are now the “new normal,” and they blame fossil fuels.
* “Current datasets indicate no significant observed trends in global tropical cyclone frequency over the past century … No robust trends in annual numbers of tropical storms, hurricanes and major hurricanes counts have been identified over the past 100 years in the North Atlantic basin.”
* “In summary, there continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale.”
* “In summary, there is low confidence in observed trends in small-scale severe weather phenomena such as hail and thunderstorms because of historical data inhomogeneities and inadequacies in monitoring systems.”
* “Based on updated studies, AR4 [the IPCC 2007 report] conclusions regarding global increasing trends in drought since the 1970s were probably overstated.”
* “In summary, confidence in large scale changes in the intensity of extreme extra-tropical cyclones since 1900 is low.”