Climate change won’t be a smooth transition to a warmer world, warns the Tipping Points Report by Allianz and WWF. Twelve regions around the world will be especially affected by abrupt changes, among them the North Pole, the Amazon rainforest, and California.
 | Arctic sea ice floating in the Arctic Ocean. The North Pole is among the world's most sensitive regions with regards to global warming (Photo: WWF) |
We tend to think of climate change like the retreat or growth of a glacier, a slow and steady process, almost imperceptible, but following a fairly predictable, perhaps even manageable path.
That is a mistake, warns the Tipping Points Report published by Allianz and WWF. A global temperature rise of 2°C and one slightly in excess of 2°C can have fundamentally different effects.
Or to put it differently, an avalanche is a lot worse than just heavy snowfall, and it does not happen in slow motion. Pressure builds until a threshold, or tipping point is passed, and catastrophe ensues.
Things fall apart
So it is with climate change; a temperature increase ‘slightly in excess of 2°C’ will likely trigger the slow but inevitable death of most of the Amazon rainforest. That would destroy a vital carbon sink and a giant water tap for regional agriculture, hydropower, and drinking.
With global warming a smooth transition into the future is unlikely, says the report. Instead expect step changes as climate tipping points are passed. Economic, social, and political upheaval will likely follow. The impacts on insurers such as Allianz will be profound.
Co-author Tim Lenton explains the Tipping Points concept
Sea level rises, unpredictable monsoons in India, Amazon die-back, and the desertification of Southwest North America (California and neighboring states) are the most significant climate change catastrophes we face, according to the report’s authors from the Tyndall Centre for Climate Change Research.
In the Southwestern U.S. the tipping point has probably already been passed. The scientists now predict that levels of aridity last seen in the 1930s Dust Bowl will have become the norm by mid-century.
However, in some cases the report offers reassurance. Permafrost melt in Eastern Siberia could release greenhouse gases CO2 and methane. But it would require an extreme 9 degrees Celsius surface warming for the system to tip. Claims that the release of greenhouse gases trapped in the permafrost will lead to runaway global warming are “grossly exaggerated,” the authors conclude.
Points of no Return?
The phrase ‘tipping point’ describes the concept that “a small change can make a big difference” to a particular part of the Earth’s ecosystem.
Tipping points include cases of abrupt climate change, and slow changes that occur over decades or centuries. Such transitions can be both reversible and irreversible. In some cases, passing the tipping point is barely perceptible, but it still makes an impact on the future.
The term "tipping element" describes those ecosystems that could be forced past a tipping point.
The report focuses on 12 of the most urgent or “policy-relevant” tipping elements where human activity could have a decisive influence on whether a tipping point is passed.
It assesses their current status, where their tipping points lie, what it takes to trigger them, and the likely impacts of passing the tipping points.
 | Animation (click on the image to start)Climate Tipping Points can trigger radical environmental change. See which regions will be most affected |
The elements fall into three categories:
- melting ice and permafrost;
- climate phenomena like El Nino and the ‘Gulf Stream’ that influence other elements;
- changing rainfall patterns in the tropics and sub-tropics
The report then identifies four sets of risks associated with these elements and the impacts they entail.
- sea level rise
- unstable monsoon in India
- drought in Amazonia
- drought in Southwest North America
Sea Level Rises
Just one example: Sea level rise as predicted by the Tipping Points study differs largely from the rather conservative findings of the Intergovernmental Panel on Climate Change (IPCC). Melting polar ice sheets, ignored by the IPCC, would make a 0.5 meter rise by 2050 possible, the Tipping Points report finds.
The Greenland ice sheet, for example, contains enough water for up to 7 meters of global sea level rise. With 1 to 4 degrees of global warming above 1980-1999 levels it could tip into irreversible meltdown. While a total meltdown would take several hundred years, half a meter’s worth of melt this century is possible. What is worse, the rise would be bigger locally, hitting the eastern seaboard cities of the United States hardest.
A global half-meter sea level rise would almost double the number of people vulnerable to flooding worldwide, two thirds of them in Asia. It would endanger an extra 3000 billion dollars worth of coastal assets, mostly in China, the U.S., and India. In New York the exposed assets would increase by 23 percent, with major implications for insurers.
12 Major Climate Tippings Points and why Allianz and WWF care
Lessons to Learn
Unfortunately, these realities are virtually absent from policymaking and not well reflected in current mitigation or adaptation policy.
By framing policy on a global scale—the 2°C threshold for example—we forget that regional climate changes may be far more extreme, rapid, and far-reaching in their impacts. We are also too dependent on IPCC Assessment Report projections which have in some cases been made redundant by more recent evidence, the Arctic sea-ice melt being a prime example.
And because there has been no concerted effort to reduce carbon emissions we are almost certain to breach the 2°C threshold this century. The climate change lag effect means that we could already be irrevocably committed to tipping points we don’t even know about yet.
The Tipping Points Report aims to help rectify this global failure of imagination before passing a global tipping point of no return.
editor: James Tulloch
publishing date: November 23, 2009
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Underestimate
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