In a paper published in Geophysical Research Letters of the American Geophysical Union (AGU) earlier this month, climate researchers have found that another prediction in the UN’s IPCC reports — what Al Gore likes to call “settled science” — is simply wrong, and that IPCC’s predicted rise in sea level over the next century is likely not going to happen.
First let me quote from the AGU’s own description of the paper, sent out to reporters to highlight important new findings:
With the power to drown low-lying nations, destroy infrastructure, and seriously affect sensitive
coastal ecosystems, sea level rise may be one of the most readily apparent consequences of global warming that is already under way. However, the sources of the rising waters, and the dynamics driving them, are not so clear. Melting land-locked glaciers, shrinking ice sheets over Greenland and Antarctica, and the ocean’s thermal expansion will all play a part, but the expected contribution from each of these sources is still up for debate. Previous studies have suggested that thermal expansion driven by rising sea surface temperatures will account for up to 70 percent of sea level rise in the near future, but research by McKay et al. suggests this may be a drastic overestimate.
What McKay et al. found is that the thermal expansion of the oceans actually contributed less than 1 percent of sea level rise during the last ice age., which means that the Antarctic ice sheet had to have contributed the bulk of the water for the almost 20 feet of sea level rise that occurred.
The problem this poses for modern predictions of sea-level rise is that the Antarctic ice sheet today does not appear to be melting. Thus, in order to produce the end-of-the-world scenarios that the global warming scientists like so much, the IPCC scientists assumed that the thermal expansion of the ocean would contribute most of the sea-level rise. To quote the 2007 IPCC report:
In all scenarios, the central estimate for thermal expansion by the end of the century is 70 to 75% of the central estimate for the sea level rise.
This number, however, was not really based on any good data, something the IPCC does admit. The reason it exists, however, is because the IPCC scientists do have better data on the melting (or not melting) of the glaciers and icecaps of Greenland and Antarctica, and these do not produce enough water to produce the sea-level rise these global warming activists want. Without thermal expansion, the oceans could not rise significantly, even if the world warms as much as the IPCC says.
So, the IPCC scientists guessed that thermal expansion had to be a major contributor to sea-level rise, estimating its contribution to be anywhere from 55 to 70 percent of the total.
Let me highlight the differences:
IPCC estimate: 55 to 70 percent of the total.
New data: less than 1 percent of the total.
The IPCC’s estimate seems a bit wrong, eh?
Above all, this result does not prove anything. What happened during the last major sea-level rise in the last ice age might not be a good proxy for sea-level rise in the future. Also, these new results could easily be incorrect, as they are trying to figure out what happened a hundred thousand years ago using limited data and computer models.
What this result does prove is the continuing uncertainty of climate science. We simply don’t know enough to truly understand what is happening to the earth’s climate. And anyone who says we do (Hi Al Gore!) is showing themselves to be an untrustworthy source of information, completely ignorant of the complexity of the science.