Joe over at Climate Progress once again points us to stake-raising news, this time in an article just published in Science (subscription required). The gist of it is that forecasts from in the latest IPCC report underestimate the pace and impact of current changes due to global warming. The broad consensus required among scientists and participating national agendas to publish the IPCC's conclusions served as a censor to many findings which are now being confirmed as accurate.
The emphasis on consensus in IPCC reports, however, has put the spotlight on expected outcomes, which then become anchored via numerical estimates in the minds of policy-makers. With the general credibility of the science of climate change established, it is now equally important that policy-makers understand the more extreme possibilities that consensus may exclude or downplay.The IPCC group did not include many of the feedback effects on ice sheet melting or carbon emissions released from natural storage sources as temperatures rise. These effects - which are well under way right now - stand to accelerate impacts such as sea level rise well beyond the stated limits in the IPCC's conclusions. This is critical information for dynamic risk assessment, preparation, adaptation and certainly for mitigation action.
[N]ational governments now need to confront a more fundamental question of how often they need comprehensive assessments of climate change. Addressing the special risks entailed in particular aspects of the climate system, like the ice sheets or carbon cycle, might be better approached by increasing the number of concise, highly focused special reports that can be completed relatively quickly by smaller groups, perhaps even by competing teams of experts. At this juncture, full assessments emphasizing consensus, which are a major drain on participants and a deflection from research, may not be needed more than once per decade.