THE RISING SEA AND THE IPCC

In its 2007 report, the Intergovernmental Panel on Climate Change (IPCC) estimated that sea level will rise as much as 59 cm in the next century. This estimate does not include any "dynamical" contributions from the Greenland and Antarctic ice sheets. In the last decade, however, there is evidence of a dramatic increase in such dynamical meltwater loss from both ice sheets. Recent studies by Rigot and associates suggest that in 2006, Greenland and Antarctica contributed equal amounts of meltwater to the ocean. An indication of how fast our perceptions are changing is the fact that Antarctica was not even considered as a factor in 21st century sea-level rise in the 2001 IPCC report. In the IPCC's discussion of shoreline erosion related to sea-level rise, the Bruun Rule is mentioned favorably. The Bruun Rule has no basis in reality, yet the wide-spread understanding that for every one foot of sea-level rise a sandy shoreline will retreat 100-200 feet is based on past Bruun Rule projections. In the IPCC policymaker reports, the writing is very complex and, in many circles, the fact that the 59 cm upper range estimate does not include ice sheet contribution is not recognized. The lesson to be learned is that future IPCC documents for policymakers must be edited for eighth-grade-level reading.