It is well known that the IPCC projections for sea-level rise are low. There are many reasons for this, but perhaps the main reason is the fact that the IPCC basically ignore sea-level rise contributions from the melting Greenland and Antarctic ice sheets:
The IPCC range assumes a near-zero net contribution of the Greenland and Antarctic ice sheets to future sea level rise, on the basis that Antarctica is expected to gain mass from an increase in snowfall. Observations show, however, that both ice sheets have been losing mass at an accelerating rate over the past two decades
As the figure at the top of this post indicates more recent estimates for sea-level rise are substantially higher, but significant uncertainties still remain. Those uncertainties, however, aren’t comforting, as a seal-level rise of 2+ meters is a truly frightening prospect. Even the low end estimates are worrisome.
The bottom line is that the IPCC is inherently conservative, despite what one hears in the media. It’s high end estimate is roughly the same as the low end estimates from studies that have come later.
Michael Tobis’ diagram of the climate change debate is helpful in understanding the range of opinions within the scientific community and the media.
The question is how do we get the media to report in the full spectrum of informed opinion, rather than just the lower end of the bell curve?
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