Revi,
Relevant to this discussion is something Cid just put out on his Runaway GW thread:
Climate 'tipping points' may arrive without warning
Quote:
"Many scientists are looking for the warning signs that herald sudden changes in natural systems, in hopes of forestalling those changes, or improving our preparations for them," said UC Davis theoretical ecologist Alan Hastings. "Our new study found, unfortunately, that regime shifts with potentially large consequences can happen without warning — systems can ‘tip’ precipitously.
"This means that some effects of global climate change on ecosystems can be seen only once the effects are dramatic. By that point returning the system to a desirable state will be difficult, if not impossible."
Scientists widely agree that global climate change is already causing major environmental effects, such as changes in the frequency and intensity of precipitation, droughts, heat waves and wildfires; rising sea level; water shortages in arid regions; new and larger pest outbreaks afflicting crops and forests; and expanding ranges for tropical pathogens that cause human illness.
And they fear that worse is in store. As U.S. presidential science adviser John Holdren (not an author of the new UC Davis study) recently told a congressional committee: "Climate scientists worry about 'tipping points' … thresholds beyond which a small additional increase in average temperature or some associated climate variable results in major changes to the affected system."
Among the tipping points Holdren listed were: the complete disappearance of Arctic sea ice in summer, leading to drastic changes in ocean circulation and climate patterns across the whole Northern Hemisphere; acceleration of ice loss from the Greenland and Antarctic ice sheets, driving rates of sea-level increase to 6 feet or more per century; and ocean acidification from carbon dioxide absorption, causing massive disruption in ocean food webs.
The new UC Davis study, "Regime shifts in ecological systems can occur with no warning," was supported by the Advancing Theory in Biology program at the U.S. National Science Foundation and was published online today (Feb. 9) by the journal Ecology Letters, in its Early View feature.
link
http://www.universityofcalifornia.edu/n ... icle/22806Quote:
Predicting regime shifts – drastic changes in dynamic behaviour – is a key challenge in ecology and other fields. Here we show that the class of ecological systems that will exhibit leading indicators of regime shifts is limited, and that there is a set of ecological models and, therefore, also likely to be a class of natural systems for which there will be no forewarning of a regime change. We first describe how nonlinearities in combination with environmental variability lead to model descriptions that will not have smooth potentials, concluding that many ecological systems are described by systems without smooth potentials and thus will not show typical leading indicators of regime shifts.
Abstract
In other words, we'll just be cruising along happy as a clam, then BOOM!, the ecological system we were born into and are evolutionarily adapted to, ceases to exist suddenly, never to return. No warning, irreversible.