Richard Kerr has an excellent article in today’s Science ((Pushing the Scary Side of Global Warming, Science 8 June 2007: 1412-1415, sub. req.)) looking at the discomfort scientists face in going beyond the IPCC’s conclusions on the extent to which sea level might rise over the next century. The problem here is how to approach public communication and public policy in an area where the science is moving considerably faster than the consensus-identification process of the IPCC:
(James Hansen) finds himself at the head of an informal movement to again rouse the public and policymakers. This time he worries that sea level could rise several disastrous meters by the end of the century, as the warming he heralded sends the great ice sheets rumbling toward the sea. If nothing is done to rein in greenhouse gas emissions, he says, “I just can’t imagine that you could keep sea-level rise under a meter.” Then the sea would flood many kilometers inland along the world’s low-lying coasts, from Florida to Bangladesh.
That was Hansen’s warning to Congress in late April, but it’s not the message that came out of the U.N.’s Intergovernmental Panel on Climate Change (IPCC) in early February. Many news reports gave the impression that the prestigious international assessment actually downgraded the risk of imminent sea-level rise to a small fraction of a meter.
So Hansen seems to be out on a limb, again.
The contrary voice in Kerr’s story comes from Hans von Storch:
“When we speak to the public, we should not rely on the new result,” argues Hans von Storch of the GKSS Institute for Coastal Research in Geesthacht, Germany. “The newest results are not necessarily the best ones. The IPCC should represent a certain filter. That every taxicab driver knows about [the latest result] is a bit premature.”