Climate change and rising temperatures are Earth systems past critical states, after which climate change will become irreversible and would lead to catastrophic and irreversible consequences for humanity.
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Climate Tipping Points - Big Risks in the Earth System
The tipping point in the Earth's system is a threshold that, if surpassed, can result in significant changes to the climate system.
The Earth's system tends to stay stable as the global temperature rises, but above a certain global temperature threshold, even minute disruptions might shift it into a qualitatively new state.
The threshold behavior is based on self-reinforcing mechanisms; once tipped, they continue even without external forcing. There is a chance that feedback loops will cause the Earth system to trigger other tipping points and start a domino-like chain reaction.
The Intergovernmental Panel on Climatic Change (IPCC) initially introduced the concept of climate tipping points 20 years ago. The IPCC describes a tipping point as an irreversible climate system shift.
While the precise thresholds of climate change that will set off tipping points remain unknown, the likelihood of crossing these points increases with an rise in global temperatures.
What are the Tipping Points of Climate Change? Is 1.5 °C a Tipping Point?
Although 1.5 °C is not a tipping point, it is a temperature threshold that would set off most tipping points.
Six critical tipping points likely to be crossed are:
- Greenland ice sheet meltdown
- Sudden thawing of the northern permafrost
- West Antarctic ice sheet meltdown
- Abrupt sea ice loss in the Barents Sea
- North Atlantic polar region's ocean circulation collapse
- Low-latitude coral reef die-off
Greenland ice sheet meltdown
Global warming has accelerated Greenland's ice loss in the summer season. Therefore, the ice sheet is getting thinner and decreasing in height. Evidence suggests that a global temperature increase of 1.5 °C is the threshold at which ice sheets will begin to melt permanently.
If the ice sheet melts completely, it could increase global sea levels by seven meters.
Sudden thawing of the northern permafrost
Approximately a thousand billion tons of carbon is stored in the upper layer of permafrost. Surface layer degradation exposes deeper soil to melting and breakdown, accelerating thermokarst development.
The projected threshold for this climate shift is 1.5 °C. A sudden thaw might enhance carbon emissions from northern permafrost soils by 50-100 percent and could lead to a large-scale collapse of boreal permafrost.
West Antarctic ice sheet meltdown
Huge chunks of the massive West Antarctic ice sheet's foundation depend on submarine continental bedrock. This topography makes it possible for specific flow dynamics to collapse the West Antarctic ice sheet.
When the ice melts below a specific threshold, instability occurs because of rising ocean temperatures. The onset of self-perpetuating feedback results in an acceleration of ice loss.
The tipping point is projected to be a 1.5 °C global temperature rise. If the ice sheet melts, it will raise the global sea level by approximately three meters.
Abrupt sea ice loss in the Barents Sea
Atlantic warm water influx amplifies the loss of Barents Sea ice. The tipping point or an abrupt loss will reach 1.6 °C. Loss of sea ice in the Barents Sea will considerably affect atmospheric circulation, European climate, and possibly the Atlantic meridional overturning circulation.
North Atlantic polar region's ocean circulation collapse
The Atlantic meridional overturning circulation is like a conveyor belt. It transports warm water to the northern region and, after cooling it, brings it back to the southern area. This circulation mechanism will become slower as freshwater production from melting glaciers in northern latitudes rises.
An increase in the global mean temperature of 4 °C will tip the balance. This collapse will have serious consequences on precipitation and temperature patterns, including weakening of the monsoon in Africa and Asia, depletion of natural carbon sinks, and warming of the southern hemisphere.
Low-latitude coral reef die-off
Coral reefs are endangered by various human activities, including direct damages, overfishing, ocean acidification and sedimentation. However, when ocean temperature crosses a particular threshold, coral reefs repel their symbiotic algae, resulting in coral bleaching and subsequent die-off.
The anticipated threshold for wide-spread die-off is 1.5 °C. Subtropical and tropical coral reefs significantly impact the ocean's carbon cycles and food web and are vital to the lives of millions of people worldwide.
Die-off eliminates all of these ecological functions of coral reefs.
What Will Happen with Climate Change in 10 Years?
Continued greenhouse gas emissions will worsen climate change. It is anticipated that future changes will include a warmer and more acidic ocean, a warmer atmosphere, sea level rise, and more drastic changes in precipitation patterns. The global climate is expected to continue warming for the rest of the century.
The Earth is likely no longer in a safe climate state, as the temperature has exceeded the warming by approximately 1 °C. Therefore, even the UN Paris Agreement's target of keeping global warming well below 2 °C and preferably 1.5 °C might fall short of mitigating severe climate change.
However, to even have a 50% chance of limiting global warming to 1.5 °C to avoid crossing any climate tipping points, greenhouse gas emissions must be cut in half by 2030 and eliminated by 2050.
References and Further Reading
Armstrong McKay, D. I., Staal, A., Abrams, J. F., Winkelmann, R., Sakschewski, B., Loriani, S., & Lenton, T. M. (2022). Exceeding 1.5° C global warming could trigger multiple climate tipping points. https://www.science.org/doi/10.1126/science.abn7950 (Accessed on 21 September 2022)
CarbonBrief. (2020). Explainer: Nine' tipping points' that could be triggered by climate change. [Online]. Available at: https://www.carbonbrief.org/explainer-nine-tipping-points-that-could-be-triggered-by-climate-change/ (Accessed on 22 September 2022).
Herr, A., Osaka, S., and Stone, M. (2022). The 7 climate tipping points that could change the world forever. [Online]. Grist. Available at: https://grist.org/climate-tipping-points-amazon-greenland-boreal-forest/ (Accessed on 21 September 2022).
Lenton, T. M., Rockström, J., Gaffney, O., Rahmstorf, S., Richardson, K., Steffen, W., & Schellnhuber, H. J. (2019). Climate tipping points—too risky to bet against. https://www.nature.com/articles/d41586-019-03595-0 (Accessed on 21 September 2022).
Potsdam Institute For Climate Impact Research. (2022). Tipping Elements - big risks in the Earth System. [Online]. Available at: https://www.pik-potsdam.de/en/output/infodesk/tipping-elements/tipping-elements/ (Accessed on 21 September 2022).
Stallard, E. (2022). Climate change: Six tipping points' likely' to be crossed. [Online]. BBC News. Available at: https://www.bbc.com/news/science-environment-62838627 (Accessed on 21 September 2022).
Wunderling, N., Donges, J., Kurths, J., & Winkelmann, R. (2021). Interacting tipping elements increase risk of climate domino effects under global warming. Earth System Dynamics Discussions. https://doi.org/10.5194/esd-2020-18 (Accessed on 21 September 2022)
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