How close are the “tipping points”?

“Climate tipping points” (CTPs) are a key way to frame the dangers that human activity presents to the stability of the climate. Climatological and ecological earth systems that humanity relies on for liveable temperatures, agriculture, etc — for life! — are being destabilised by rising temperatures resulting from carbon emissions, putting them under strain.

Changes in one sphere have effects in others, and risk creating runaway feedback loops (existing imbalances generating further imbalances) that can push the systems we rely on beyond the point of no return, where they can’t be mended in any short term, threatening the lives of countless millions.

Changes in one tipping point can cascade, adding to the pressure in others, and even a global CTP has been posited.

Cooperate

To avoid tipping these systems over, humanity must cooperate to reduce new carbon emissions and the greenhouse gases already in the atmosphere, monitor changes and effects, manage environments, and so on.

The usage of “tipping point” in this context became current in the early 2000s (see “We may be near tipping points”, Solidarity 702).

What systems are involved? Commonly cited are “nine global ‘core’ tipping elements which contribute substantially to Earth system functioning and seven regional “impact” tipping elements which contribute substantially to human welfare or have great value as unique features of the Earth system”.

CTPs are found

• in the cryosphere, including Arctic Sea Ice; Greenland Ice Sheet; West Antarctic Ice Sheet; East Antarctic Subglacial Basins; East Antarctic Ice Sheet; Boreal Permafrost; Mountain Glaciers

• in ocean-atmosphere (circulation) — North Atlantic subpolar gyre/Labrador-Irminger Sea convection; Atlantic Meridional Overturning Circulation (AMOC)

• and biosphere (Amazon Rainforest; Boreal Forest; Sahel Vegetation and the West African Monsoon; Low-Latitude Coral Reefs).

The research article from 2002 cited above suggests that:

“The Earth may have left a safe climate state beyond 1°C global warming. A significant likelihood of passing multiple climate tipping points exists above ~1.5°C, particularly in major ice sheets. Tipping point likelihood increases further in the Paris [2015 Paris Agreement] range of 1.5 to <2°C warming. Current policies leading to ~2 to 3°C warming are unsafe because they would likely trigger multiple climate tipping points”.

AMOC

In “A drastic tipping point may be close” ( Solidarity 766) Stuart Jordan describes the Atlantic Meridional Overturning Circulation (AMOC):

“Warm surface water from the tropics flows northwards, warming Europe and the Arctic, where it cools and descends, returning to the tropics along the ocean floor. This ‘oceanic conveyor belt’ moves at a rate of one cycle every 1,000 years, and has played a key role in creating the stable climatic conditions necessary for settled agriculture and the past 11,000 years of human development”.

He reports that scientists believe the AMOC could collapse or at least slow, and sooner than feared.

In May 2026 the UK Government examined the tipping points likely to most impact the UK, and warned: “tipping points’ precise thresholds, likelihoods and timescales remain unclear”.

Based on its survey of current science, it concluded: “It is possible that we have crossed the tipping point threshold for warm-water coral reefs…

“...widespread abrupt permafrost thaw, disintegration of the Greenland Ice Sheet and the West Antarctic Ice Sheet, and potentially the collapse of subpolar gyre convection are possible at current global warming levels [and] likely beyond 1.5°C of sustained global warming…

“...the complete collapse of the AMOC during this century is unlikely. However... expect the AMOC to weaken substantially, and a tipping point threshold committing the AMOC to later collapse may be crossed within decades.

“...dieback in the Amazon has been localised, but passing 1.5°C of sustained global warming, along with intensified deforestation, could lead to regional dieback.

“As a system loses resilience, it takes longer to recover from disturbances, and its fluctuations often become larger and more persistent. For example, more than 75% of the Amazon rainforest was assessed as having lost resilience since the early 2000s”.

The Guardian reports Professor Gustaf Hugelius from the Bolin Centre of Climate Research at Stockholm University, Sweden, warning of the danger of permafrost thawing as a result of increasingly frequent wildfires. Permafrost currently acts as an enormous carbon sink but begins to release greenhouse gases as it melts. While there is only a small likelihood of large-scale melting, even small thaws add to the difficulty of keeping global warming within the required bounds, and could have marked localised impacts.

For socialists, the purpose of monitoring what the scientists are telling us is to fuel and renew our commitment to changing the social and economic structures that threaten runaway climate change and, with them, human civilisation.