First up—what are Climatic Tipping Points? Tipping points are thresholds where a small change could push a system into a completely new state. They are based on positive feedback loops, whereby an effect of something actually reinforces the cause. With respect to the Earth’s climates, they are caused when particular impacts of global heating become unstoppable. Thus, a tipping point is an irreversible change in the climate system. Needless to say, avoiding Climatic Tipping Points is recommended.
What levels are critical?
In the past, extreme heating of 5C was thought necessary to pass tipping points, but latest evidence suggests that this could happen at much lower temperature changes, even lower than 2C.
Earth has already passed the 1C mark and temperatures will certainly rise further, due to past emissions and because greenhouse gases are still rising. Scientists further warn that one tipping point may fuel others, leading to a cascade, and have called for urgent international action.
What are some examples?
Diagram from EARTH.ORG
Scientists warn that the West Antarctic ice sheet could be be in irreversible retreat. A similar situation is occurring at the Wilkes basin in East Antarctica. The depletion of these ice sheets will raise sea levels by many metres. Also, the Gulf Stream current in the Atlantic, which warms Europe, has slowed by 15% since the mid-20th century.
About 17% of the Amazon rain forest has been lost since 1970. The tipping point where loss of forest leads to it drying out, would lie in the 20-40% range, which could turn some regions from a sink for carbon to an actual source.
In the tropics, corals are predicted to be wiped out by 2C of heating.
This is not pretty reading.
Barriers to stopping climate change
Mostly the inability of humans to collectively see the big picture:
As a few examples
- Information barriers: Authoritative, consistent and accessible information is essential for effective adaptation of policies.
- Cognitive barriers: Psychological factors influence the human ability to act on information about climate change, including our preconceptions of how urgent the need is.
- Markets may not always generate the right signals for individuals and businesses to prepare for climate change. Governments more often than not act as insurers of last resort for the choices made by others.
- Coordinating adaptation across regions can be costly and result in unintended consequences: eg. a challenge for local governments is that many adaptation decisions need to be regionally applied in order to be effective.
Preliminary results from the latest climate models suggest that global heating will be greater than expected, thus increasing the risk of tipping points. Climate tipping points are an emergency that need to be studied in order to be avoided.
Passing an irreversible tipping point would mean a system would not revert to its original state even if the forcing lessens or reverses, explains Dr Richard Wood, who leads a world-leading Climate, Cryosphere and Oceans group.
“In some cases, there is evidence that once the system has jumped to a different state, then if you remove the climate forcing, the climate system doesn’t just jump back to the original state – it stays in its changed state for some considerable time, or possibly even permanently.”
As well as ourselves, maybe there is one other powerful force in the scenario—the Earth itself. For a long time the planet has been warning us. Let’s not wait until the Earth gives us an almighty no holds barred signal.
References and further reading: