and several considerations: part 1
The situation:
A recent, very controversial, simulation suggests that the Atlantic meridional overturning circulation (AMOC) may reach a tipping point much sooner than originally thought, beginning as early as 2025, and could cause major changes in water levels and climate too fast for ready adaptation in some areas1. An excerpt:
Climate scientist Tim Lenton, director of the Global Systems Institute at the University of Exeter, has also used computer models to assess how an AMOC shutdown could affect the world’s food supply. The dramatic cooling in the Northern Hemisphere would cause a shift in the band of clouds and rainfall that encircle the globe at the tropics. The monsoons that typically deliver rain to West Africa and South Asia would become unreliable, and huge swaths of Europe and Russia would plunge into drought. As much as half of the world’s viable area for growing corn and wheat could dry out.
Since the AMOC transports heat northwards in the Atlantic, a collapse would tend to cause a significant cooling in the North Atlantic Ocean, which would drive cooler temperatures over much of the Northern Hemisphere, especially Europe and North America, and potentially across the whole hemisphere …. This, however, would compete with the effects of global warming, with the net effect depending on the magnitude of the latter. The reduced heat transport would slightly add to warming in the Southern Hemisphere. Cooler ocean temperatures in the North Atlantic would drive reduced evaporation and hence less atmospheric water vapour for precipitation ….. They would also result in an increase in Arctic sea ice. As much as half of the world’s viable area for growing corn and wheat could dry out. GTP-full-report-071223 (2).pdf
This is a frightening possibility, although not as frightening as the movie The Day After Tomorrow. More information and links can be found below in a very helpful overview from a government staff person.2 The direct effects of greater cooling on North America are but vaguely known. Even so, we can be sure that the effects elsewhere will impact us here however indirectly. While the impact on Canada and North America may be uncertain, it would be better to think ahead than to wait passively.
Thinking ahead to an ethical practice:
People should do some deliberate thinking about an ethic to hold onto as we live into that future. Attitude and action will be important. Attitude: something better than fear, thoughts of self defense, panic, or running away. Something explicit we can put out in front of ourselves like the arrowhead-shaped blade of a snow plow to break through fear, and which will inspire others to move in the same forward direction. It is often said that when troubles come our way, it’s not just the troubles themselves that determine our future, but our response to them. I maintain that what we are doing at the moment to move things along in our lives, is more important than just responding to troubles.
There are many matters to consider when planning for such an uncertain future.
1. Attitude and the lessons of COVID. This is where the ethic is important. Ethics is the practice of putting forth your values explicitly to guide you consistently, so that everyone around you knows what to expect of you – neighbours, employers, employees, co-workers, family, friends, political affiliates. Your values will predict how you will treat not only people but the rest of life around you near and far, i.e., the environment.
I suggest two primary values: generosity and compassion. Generosity means being willing to do all you can in the event for the benefit of others, as well as for yourself. It means doing not just the minimum, staying on your side of the street, in your own box. It means not giving in to distrust of others as a first response. There is a religious expression which can help with this: be as concerned for others (including the environment) as for yourself, neither more nor less. This is does not requires self-sacrifice, but it does mean walking arm–in-arm with others, all of you holding on as you move ahead without breaking away. I want to emphasize the metaphor of the snow plow (with snow as the analog of fear), as all these problems head for us. Generosity is a forward-leaning attitude and action. Think of a snow plow with an arrowhead-shaped blade thrusting forward and pushing aside the snow. This is far healthier than one with the V-shape which can only capture the snow and struggle to move forward against ever heavier loads. Fear brings defensiveness and immobility; generosity breaks through the fear that awaits us. Fear brings paralysis until anger, the flip side of fear, moves us to act without thought or morality; generosity make us act before we get to fear.
Compassion is walking with others through life, being next to them in a way that each supports the other, leading forward but accepting that not everyone can move so quickly or sure-footedly. Think of it as pushing someone in a wheelchair while someone else pushes on your back, or carries some of your gear for you, or relieves you for a while. It can mean listening to someone else’s story and telling them yours – so that no one’s life story goes untold and unheard.
We have learned some things from the COVID years which may make us pessimistic about adapting to threatening circumstances. Not everyone will limit their personal freedom for the “greater good.” Not everyone takes well to being required by law to act in a certain way; we have seen medical professionals treated terribly as they try to save people from COVID; we’ve seen outright denial that COVID is a real problem, and we’ve seen people deliberately and willfully lie about its significance. We have seen people make money by promoting hate. Lately, we’ve also seen great apathy: in my area COVID is returning quickly because so few people have been keeping up with the vaccine. Some pharmaceutical companies already suggest that the market for vaccines is too unprofitable for them to attune the next vaccine to the next variant. So even those who may desire the next shot, may find there is nothing new to get.
Peoples’ attitudes and value systems will guide how we handle crises more than will government action. We should encourage people to look at situations through our value systems, without judging them for theirs (assuming that our own well-being is not unavoidably damaged by their values).
Physics-based early warning signal shows that AMOC is on tipping course | Science Advances
AMOC: What to know about the ocean current potentially collapsing (slate.com)
The crucial tipping point scientists say could cause Atlantic Ocean collapse – The Washington Post
2An important question indeed and one that relates more broadly to the topic of tipping points, which can have profound impacts on the climate system.
- IPCC’s AR6 Working Group 1 Summary for Policymakers notes that, “Low-likelihood, high-impact outcomes could occur at global and regional scales even for global warming within the very likely range for a given GHG emissions scenario: The probability of low-likelihood, high-impact outcomes increases with higher global warming levels (high confidence). Abrupt responses and tipping points of the climate system, such as strongly increased Antarctic ice-sheet melt and forest dieback, cannot be ruled out (high confidence).” (p.27)
- Regarding AMOC, the report finds that, “The Atlantic Meridional Overturning Circulation is very likely to weaken over the 21st century for all emissions scenarios. While there is high confidence in the 21st century decline, there is only low confidence in the magnitude of the trend. There is medium confidence that there will not be an abrupt collapse before 2100. If such a collapse were to occur, it would very likely cause abrupt shifts in regional weather patterns and water cycle, such as a southward shift in the tropical rain belt, weakening of the African and Asian monsoons and strengthening of Southern Hemisphere monsoons, and drying in Europe.” (p.27)
- But as Prof. Stefan Rahmstorf writes:
- “It has long been my opinion that ‘very unlikely’, meaning less than 10% in the calibrated IPCC uncertainty jargon, is not at all reassuring for a risk we really should rule out with 99.9% probability, given the devastating consequences should a collapse occur.”
- And: “Standard climate models probably underestimate the risk”, which he further explains in his blog (2023).
The Nature article (2023) did get a lot of attention (and some mis-reporting) and critiques.
Regarding the recent Science Advances article (2024), I also found this article in The Conversation by the study authors helpful:
- “The big question – when will the Atlantic circulation reach a tipping point – remains unanswered. Observations don’t go back far enough to provide a clear result. While a recent study [i.e., the 2023 Nature article] suggested that the conveyor belt is rapidly approaching its tipping point, possibly within a few years, these statistical analyses made several assumptions that give rise to uncertainty.”
- Here’s also a reaction to the study from Prof. Stefan Rahmstorf (2024).
On tipping points, the following may be of interest:
- OECD, 2022. Climate Tipping Points: Insights for Effective Policy Action. https://www.oecd.org/environment/climate-tipping-points-abc5a69e-en.htm
- Lenton et al., 2023. Global Tipping Points. https://global-tipping-points.org/
- Video on “How 16 Tipping Points Could Push Our Entire Planet Into Crisis” by Prof. Johan Rockström: https://www.weforum.org/videos/how-16-tipping-points-could-push-our-entire-planet-into-crisis/
As for impacts on North America/Canada, if AMOC were to collapse:
- studies suggest that North America could get a few degrees cooler (but maybe less than Europe)
- Sea level rise could worsen and impact Atlantic Canada
- More potential biophysical impacts can be found on p.125 in the Global Tipping Points (2023)
Upon reconsidering... 