Top Forecaster: Climate ‘Tipping Points’ May Arrive Without Warning


This graphic shows the extent of Arctic sea ice in September 2009 (in white) compared with the median ice extent for September from 1979 to 2000 (in magenta). (U.S. National Snow and Ice Data Center/map)

A new University of California, Davis, study by a top ecological forecaster says it is harder than experts thought to

predict when sudden shifts in Earth’s natural systems will occur — a worrisome finding for scientists trying to identify the tipping points that could push climate change into an irreparable global disaster.

Large Changes

Without Warning

“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.”

May Apply to Other Complex Systems

The current study focuses on models from ecology, but its findings may be applicable to other complex systems, especially ones involving human dynamics such as harvesting of fish stocks or financial markets.

Hastings, a professor in the UC Davis Department of Environmental Science and Policy, is one of the world’s top experts in using mathematical models (sets of equations) to understand natural systems. His current studies range from researching the dynamics of salmon and cod populations to modeling plant and animal species’ response to global climate change.

In 2006, Hastings received the Robert H. MacArthur Award, the highest honor given by the Ecological Society of America.

Hastings’ collaborator and co-author on the new study, Derin Wysham, was previously a postdoctoral scholar at UC Davis and is now a research scientist in the Department of Computational and Systems Biology at the John Innes Center in Norwich, England.

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.

Bigger Changes May Be ComingDonnelly-Colt Ad

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.

More Information

The study, “Regime shifts in ecological systems can occur with no warning,” was published online by the journal Ecology Letters, in its Early View feature: .

The original article, published here:, includes some relevant comments.  Φ

3 comments for “Top Forecaster: Climate ‘Tipping Points’ May Arrive Without Warning

  1. craig
    May 1, 2010 at 12:43 pm

    * With industries, the mass distribution of goods and services humming along in a world at peace, our planet can sustain a population of about 2 billion people. That’s far more than the optimum population.

    * Without industrialized agriculture, petroleum energy and products, a peaceful world might be able to support half a billion people.

    * The world’s profit motivated bubble economies which keep the wheels turning are a house of cards which are themselves wobbling at the “tipping point”. Internal factors (like reckless opportunism by banksters) or externals (peak oil, global warming disasters, nuke plant disaster, another major false flag terrorist event) could bring it all down –and it’s likely that the population of an unpeaceful world would then sustain an uneven die-off in the high 90% range.

    * However, just the mention of overpopulation is off the table. As to advocating a “population policy”, can’t you just imagine how religious leaders, the business world, left and right political factions would scream at that? Consequently, the Great Die-Off is assured. It’s just a matter of when.

    * If sane energy and conservation policies prevail (without sane and effective population policies), perhaps the GDO can be postponed until it can take 10 billion lives and much more of this beautiful planet. At climax population it would be terrafarmed, solar paneled, wind/water turbined, and mined nearly to the exclusion of any other Gaiaen purpose.

    * Given the hammer-headed fundamentalisms in our world (among which I count spiritually challenged Randites and corporate gangsters), a rational response is to simply live as honorably and happily as we can, and to start burying time-capsules in an attempt to warn whoever/whatever next inherits our planet. Our messages as impressions in time-proven fired clay tablets seems the best way to go.

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