Climate change: are we past the point of no return?

Climate change won’t be a smooth transition, warn Allianz and WWF in a report flagging potentially catastrophic ecological tipping points.
Arctic sea ice floating in the Arctic Ocean. The North Pole is among the world\'s most sensitive .../ Credits: WWF

Article at a glance

We tend to think of climate change as a slow and steady process, following a fairly predictable, even manageable path. That is a mistake, warns the 'Tipping Points Report' published by Allianz and WWF.

With global warming a smooth transition is unlikely, says the report. Instead there may be disruptive, sudden changes as key ecological thresholds, or tipping points, are breached.

As report co-author Tim Lenton describes in the film below, tipping points describes the concept that “a small change can make a big difference” to a particular part of the Earth’s ecosystem, changing its state fundamentally.

Such transitions may be irreversible. In some cases, passing the tipping point is barely perceptible, but it still makes a large impact on the future.


The term "tipping element" describes those environmental processes 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. 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

Points of no return?

The best known tipping point is the global warming threshold of 2 degrees Celsius. A temperature rise slightly above that is considered highly dangerous by climate scientists. It could, for instance, trigger dieback of much of the Amazon rainforest, destroying a vital carbon sink and source of fresh water.

Sea level rises, unpredictable monsoons in India, and the desertification of the Southwest region of North America are other key tipping points, according to the report’s authors from the Tyndall Centre for Climate Change Research.

In the Southwestern US the tipping point has probably already been passed. The scientists now predict that by mid-century levels of aridity last seen in the 1930s will be the norm.

The study suggests melting polar ice sheets would make possible a 0.5 meter sea level rise by 2050. 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.

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 $3 trillion of coastal assets, mostly in China, the US, and India. In New York, the exposed assets would increase by 23%.

In some cases the report offers more 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.

Regional extremes

Unfortunately, tipping points are largely absent from policymaking discussions and not well reflected in current climate change policies.

For instance, by framing policy on a global scale—the 2 degrees threshold for example—we forget that regional climate changes may be far more extreme.

We may also be overly dependent on reports from the Intergovernmental Panel on Climate Change (IPCC) which have in some cases been challenged by more recent evidence (see 'Polar expert brands climate change report “complacent”').

And because there has been no concerted effort to reduce carbon emissions we are almost certain to breach the 2 degrees 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.

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Comments (9)

keerthi kumar: 21.12.2010, 16:10

It is good information, all govt's should take immediate action by educate the people immediately.All countries should come forward to save this earth.

John Toxey: 09.03.2010, 23:57

We are past the tipping point. The Kyoto Emissions Pact was too late in coming. You all have underestimated the rate of the warming. It will be in decades rather than centuries and will continue to excelerate until a new equilibrium is reached.I have been studying the facts for years and your predictions are all off. You have no real clue as to the impact of this warming. You are all whistling in the dark.
No one talks of the possible positive aspects of the warming. Many areas now not warm might be able to sustain agriculture.
Love to you all and realize that there is nothing we can now do to stop or even slow it down.
John Newbern Toxey III

Thilo Kunzemann: 22.02.2010, 11:19

Many thanks for your comment. In fact, oxygen levels in the atmosphere are not increasing, its the CO2 levels that are increasing. This should already answers your question regarding the oxidation of metals.

The increase of CO2 levels will, theoretically, make plants grow faster. Global warming, however, could make certain areas drier, which will again limits growth. Northern latitudes will probably see increased growth and longer growth periods, while regions closer to the equator won't profit because of increased weather extremes (floods, drought).

Harry Nafpliotis: 13.02.2010, 20:35

Assuming that oxygen levels are increasing what would happen to the normal growth of plants,insects and animals? Furthermore,what would happen to the everyday metal- made appliances from overly exposed to increased oxygen levels? The fact remains that we need the present levels of carbon dioxide which in natural balance with oxygen makes possible our existence.

Mackenzie Jones: 26.01.2010, 03:12

This web site has helped me a great deal. I am in grade 8 and am doing a speech on climate chang/global warming/changing water currents/ and the new phenomeon of 2012...these pages are full of intresting information on the El Ninos and La Nina which was great because that is one of the 4 main points in my speech! This was a great web sit, and i only wish this website had information for every topic in the world, that way all my homework and assinments would be done in a flash. Thanks again!

BINAY SANDWAR: 22.12.2009, 08:19


joe samuels: 19.12.2009, 17:58

It is warmer, but no one knows the cause nor is any agreement will do a thing. "Tipping points" are spoken of on this blog as if it is fact when the fact is it is an opinion. It may or may not be correct. But, remember, in 1980, El Nino happened every 7 years. By 1988, that "fact" was found to be false. This guy is reasonable, rational and unbiased. In other words he has the right approach. Everyone should consider this.

James Emery: 18.12.2009, 14:48

Carbon tax will slap 3000 dollars of debt on every newborn child in all participating nation states. i've never heard of a tax across multiple nations, or one that taxes the air, the water, and the flow of you're blood, but making people pay the fat man al gore for all of this will somehow change the endless cycle of cyclical consumption, profit is the only motivation behind gore's actions,

Brad Arnold: 27.11.2009, 08:07

Sadly, current climate models dramatically underestimate future abrupt climate change because ecosystem collapse is underestimated:

Leemans and Eickhout (2004) found that adaptive capacity decreases rapidly with an increasing rate of climate change. Their study finds that five percent of all ecosystems cannot adapt more quickly than 0.1 °C per decade over time.
Forests will be among the ecosystems to experience problems first because their ability to migrate to stay within the climate zone they are adapted to is limited. If the rate is 0.3 °C per decade, 15 percent of ecosystems will not be able to adapt. If the rate should exceed 0.4 °C per decade, all ecosystems will be quickly destroyed, opportunistic species will dominate, and the breakdown of biological material will lead to even greater emissions of CO2. This will in turn increase the rate of warming.

Reference: Leemans og Eickhout, 2004, Another reason for concern: regional and global impacts on ecosystems for different levels of climate change, Global Environmental Change 14, 219–228.

By the way, the world is committed to at least 2C of future warming. Here is what Climate Code Red says:
--Human emissions have so far produced a global average temperature increase of 0.8 degree C.
--There is another 0.6 degree C. to come due to "thermal inertia", or lags in the system, taking the total long-term global warming induced by human emissions so far to 1.4 degree C.
--If human total emissions continue as they are to 2030 (and don't increase 60% as projected) this would likely add more than 0.4 degrees C. to the system in the next two decades, taking the long-term effect by 2030 to at least 1.7 degrees C. (A 0.3 degree C. increase is predicted for the period 2004-2014 alone by Smith, Cusack et al, 2007).
--Then add the 0.3 degree C. albedo flip effect from the now imminent loss of the Arctic sea ice, and the rise in the system by 2030 is at least 2 degree. C, assuming very optimistically that emissions don't increase at all above their present annual rate! When we consider the potential permafrost releases and the effect of carbon sinks losing capacity, we are on the road to a hellish future, not for what we will do, but WHAT WE HAVE ALREADY DONE.

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