27th June 2025
Tipping Points
Four years ago I wrote about the tipping points likely accelerate the climate crisis. In June 2021 the concentration of carbon dioxide in the atmosphere stood at 418.93 parts per million (ppm). As of May 2025 the concentration of carbon dioxide stands at 430.51 ppm (https://gml.noaa.gov/ccgg/trends/mlo.html) As the safe level of carbon dioxide lies somewhere between 280 and 350ppm, we were clearly in a danger zone in 2021, since when things have got worse rather than better.
Here is the 2021 article, below which is a comment from the Ecologist journal as to where we currently stand vis a vis the likelihood of triggering any or all of the global climate tipping points and another article from the Guardian.
In Alan Stoppard’s play Jumpers, George Moore, a philosophy professor, muses that at some point in history, the balance of believers versus non believers tipped from the former being the majority to the latter. He suspected it was the decline in woollen socks in preference for nylon ones that precipitated this tipping point: woollen socks kept the wearer in mind of the link between nature and daily life and thus a link between a divine creator and daily life.
We have seen a number of social issues reach a tipping point: the acceptability or not of smoking, the acceptability or not of drink-driving, the use of plastic bags versus reusable versions, and most recently the wearing of face masks. At some point social pressure, social acceptance and/ or social understanding shifted in favour of a new status quo. Social norms are not fixed and what interests me is what initiates and sustains the sequence of changes that lead us to change our patterns of behaviour and belief.
The Intergovernmental Panel on Climate Change is increasingly concerned that the current rate of global warming could reach a number of tipping points. One such scenario centres on the Arctic. As temperatures increase so the frozen soil have melted – not just the surface levels which is ‘normal’ but also the deeper levels of the permafrost. As they melt they release methane locked away for thousands of years ago. This flammable gas has led to outbreaks of wild fires across the Arctic destroying large areas of the tundra’s flora and fauna. Methane is one of the greenhouse gases and has a warming effect on the climate 80 times that of carbon dioxide. The melting of the permafrost in the Arctic disproportionately adds to the heating of the global environment and to the consequential further melting of frozen soils as well as sea ice. In other words the rise in temperatures that allows the Artic to thaw triggers a sequence of events that leads to a further upward spiralling of temperatures.
Other tipping points have also been observed: in Greenland where the more the ice-sheet melts the faster is the rate of melting in subsequent years, leading both to rising sea levels and a likely reversal of the Gulf Stream*; in the Amazon the loss of rainforest (due to commercial felling) is expanding the area of land covered by Savannah grass lands causing rising air temperatures and depleting levels of rainfall which both threatened the natural regeneration of the rainforest; in the tropics rising sea temperatures bleach coral reefs as plant and animal life grows more slowly or dies off completely. As these living forms die so they absorb less carbon dioxide which in turn compounds rising air and sea temperatures.
Worryingly the danger presented by such scenarios doesn’t become apparent until the tipping point has been reached! This means preventative action needs to be taken before the affects of the danger are felt. We have in recent months learnt the lesson that the way to limit rocketing covid infections is to follow lockdown procedures before the number of cases becomes unmanageable. Can we do the same to prevent the extreme effects of climate change? Can we as individuals rapidly decarbonise our lifestyles now to safeguard the future for ourselves and our grandchildren? Can we create the social groundswell needed to make a carbon neutral lifestyle the norm? Can we create the popular groundswell to change the direction of our political leaders?
- Rather than the Gulf Stream, the tipping point now being highlighted by scientists is the loss of the Atlantic meridional overturning circulation or AMOC. It’s loss would lead to a rapidly cooling climate for the British Isles. (for more information see https://www.theguardian.com/environment/2024/oct/23/we-dont-know-where-the-tipping-point-is-climate-expert-on-potential-collapse-of-atlantic-circulation?CMP=Share_iOSApp_Other)
“Multiple climate tipping points are likely to be triggered if global policies stay on their current course, new research shows.
Scientists assessed the risk of tipping in 16 different parts of the Earth system – ranging from the collapse of major ice sheets to the dieback of tropical coral reefs and vast forests.
Their most conservative estimate is a 62 per cent risk of triggering these tipping points on average, based on current policies and the resulting global warming.
However, more sustainable future pathways – with lower greenhouse gas emissions – significantly reduce the risk of tipping points.
The study, by the universities of Exeter and Hamburg, also found that carbon released by certain tipping points – Amazon rainforest dieback and permafrost thaw – is unlikely to cause enough warming to trigger other tipping points.
“The good news from our study is that the power to prevent climate tipping points is still in our hands,” said lead author Jakob Deutloff.
“By moving towards a more sustainable future with lower emissions, the risk of triggering these tipping points is significantly reduced.” https://theecologist.org/2025/may/21/cascading-climate-tipping-points-likely
The Green Tau 