Climate ‘tipping points’ may arrive without warning, says top forecaster:
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.
“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.”
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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.
And we thought Mother Nature would be oh so convenient and give us lots of advance notice that Bad Stuff was about to happen… why, exactly?
Some of these potentially sudden shifts, like the desertification of “bread-basket” zones and the unpredictable shifting of ocean currents commensurate with the disappearing ice cap (and the drastic weather changes that are sure to follow) — make the whole “rising sea level” problem seem rather innocuous. Where, for example, are Miami’s submerging residents going to flee when faced with nothing but deserts to the north?
What a scary century we’ve cooked up for ourselves.
Mark: Yep, that’s a key point a lot of people have been missing–it’s not the sea level rise, but the other water effects that will bite us the hardest. The poles get the most attention, but the melting with the greatest potential for human impact happens in mountain glaciers. Less summer runoff means less water electricity generation (hydro + cooling thermoelectric plants), plus less water for human consumption, hygiene, agriculture, industrial use, etc.
Think about how we’ve built up our infrastructure around the world. The placement of cities, businesses, electricity generating plants, and basically everything “permanent” we build all has embedded assumption, sometimes very subtle, about what the surrounding conditions will be like “forever”. As the global climate changes (to coin a phrase), those assumptions are suddenly incorrect in many places, leaving us to figure out how to adapt to the new reality or move/replace those pieces of the infrastructure.