Nature Geoscience
Published online: 26 July 2009 | doi:10.1038/ngeo587Constraints on future sea-level rise from past sea-level change
Mark Siddall, Thomas F. Stocker & Peter U. Clark
It is difficult to project sea-level rise in response to warming climates by the end of the century, especially because the response of the Greenland and Antarctic ice sheets to warming is not well understood1. However, sea-level fluctuations in response to changing climate have been reconstructed for the past 22,000 years from fossil data, a period that covers the transition from the Last Glacial Maximum to the warm Holocene interglacial period. Here we present a simple model of the integrated sea-level response to temperature change that implicitly includes contributions from the thermal expansion and the reduction of continental ice. Our model explains much of the centennial-scale variability observed over the past 22,000 years, and estimates 4–24 cm of sea-level rise during the twentieth century, in agreement with the Fourth Assessment Report of the Intergovernmental Panel on Climate Change1 (IPCC). In response to the minimum (1.1 °C) and maximum (6.4 °C) warming projected for AD 2100 by the IPCC models, our model predicts 7 and 82 cm of sea-level rise by the end of the twenty-first century, respectively. The range of sea-level rise is slightly larger than the estimates from the IPCC models of 18–76 cm, but is sufficiently similar to increase confidence in the projections.
26 July 2009
Yawn
From Nature Geoscience comes this less-than-titillating abstract:
Nothing to see here, move along.
2 comments:
Dr. Pielke,
1) Okay, I’ll try to resist the urge to debunk Dean. He seems to do that quite nicely on his own.
2) Actually, the IPCC fourth assessment report suggested 18cm-59cm of sea level rise by 2100 (not the 18cm-76cm suggested in your citation). See Table 3.1 on page 45 of this (rather large) IPCC link.
3) Obviously, the fundamental problem with a study like this one is the artificial constraint of working within the warming boundaries assumed by the IPCC.
A) Schwartz 2007, calculates climate sensitivity -- the impact upon temperature of doubling of CO2 from pre-industrial levels -- at 1.1C. The IPCC attributes the 0.7C of warming during the last century to anthropogenic CO2. This leaves only 0.4C of warming to come by 2100 (assuming that is the point at which we double the CO2 famine levels represented by pre-industrial levels of CO2).
0.4C (Schwartz, 2007) / 1.1C (IPCC low end) * 7cm (low end sea level rise from your cited study) = 2.5cm (a more reasonable estimate of sea level rise by 2100).
B) Dr. Gray (0.2-0.3 degree C) and Dr. Lindzen (0.64C) have calculated climate sensitivity figures well below Schwartz, 2007.
3) But, even the excessively high calculation of 7cm–82 cm of sea level rise over the next century isn’t enough to scare anybody into a panic.
Yawn indeed…
I guess the alarmists will have to resort to reruns of the Al Gore movie. Peer reviewed science seems to lack the impact they seek.
Given what we know about the way the IPCC does science, why would the fact that their results are "sufficiently similar" to the IPCC's increase confidence in their projections?
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