Given the EPA has been heavily censored by the Bush administration, and may be one of the worst places to look at research on Global Warming, the new report coming out from the IPCC on Feb 2, 2007 should be significantly better. As a subset of that research the University of Colorado seems the best place to focus on information about Sea Level Change outside of the hundreds of articles about it that can be found on the Daily Kos as for example on 3/24/06, 3/27/06, and 5/4/06
more below the fold...
When the rate of change changes at an increasing rate you get an exponential curve. In pure mathematics an exponential curve looks a lot like the wave above. Only in pure mathematics can an exponential curve go to infinity, in social systems it invariably breaks down.
Temperatures are rising fastest near urban areas, areas of oil production, and where the Siberian tundra melting is releasing large amounts of methane into the atmosphere.
Rising Sea Levels are related to rising temperatures not just because the polar ice is melting but because the oceans have a coefficient of expansion that means as temperatures increase they get bigger
Not just Sea Levels but also the Rate of Change in the Estimated Increase of Sea Level Change have been increasing at an increasing rate. There is a new term for this Abrupt non-linear climate change. This links to a paper on its irreversibility and surprise
Any discussion of the benefits of greenhouse gas (GHG) mitigation measures should take into consideration the full range of
possible climate change outcomes, including impacts that remain highly uncertain, like surprises and other climate irreversibilities.
Real-world coupling between complex systems can cause them to exhibit new collective behaviours that are not clearly demonstrable
by models that do not include such coupling.
Through examples from ocean circulation and atmosphere–biosphere interactions, this paper demonstrates that external forcings such as increases in GHG concentrations can push complex systems from one equilibrium state to another, with non-linear abrupt change as a possible consequence.
Furthermore, the harder and faster a system is perturbed, the higher the likelihood of such surprises—a conclusion that has significant bearing on the assessment of the potential benefits of the timing and stringency of GHG abatement measures. The paper concludes with a perspective on how to better incorporate uncertainty and surprise into integrated assessment models of climate change.
Sea level change is also affected by tides, isostatic rebounding, aubsidence, and where you happen to be located on the globe.
Back in the eighties the EPA was talking about a rise of a few mm by 2100. Now the IPCC is talking about a rise of a few meters by 2050. The scientists are agreed that the range of uncertainty about how much and when is large so they tend to take a fair and balanced approach that choses a trend line somewhere in the mid range of possible results.
A lot of the uncertainty comes from the hope that there may be possible effects of mediation such as pumping CO2 from the atmosphere back into the ground or running out of fossil fuels, or human die offs. Some of the pessimism comes from the possibility that we are already experiencing abrupt non linear change