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by David Spratt
The need to cool the planet in order to avoid collapse scenarios needs to be taken seriously.
Breakthrough recently released Climate dominoes: Tipping points risks for critical climate systems, a report on climate system tipping points and cascading effects.
This is based on our blog series earlier this year, now with a foreword by Sir David King, the former UK chief scientist and founder of the Centre for Climate Repair at Cambridge. King writes that:
“... there is a blind-spot in the IPCC analysis, in that the severity of human influence on our planetary ecosystems is leading us toward a range of irreversible tipping points; uncertainties about which we have limited knowledge. The first of these, in the Arctic Circle region, appears already to have tipped, leading to the series of devastating extreme weather events around the Northern Hemisphere last summer. This blind-spot is the subject of Breakthrough’s latest Climate Dominoes report, which is a critically important analysis of the state of the world today and the immediate threat to our global economic systems from these tipping points. It is a sober call for all countries to follow a critical analysis pathway for dealing with climate change as the emergency that it is. It should be read and acted on by governments and their advisors, by the financial communities of the world, and by scientists, engineers, social scientists and philosophers. Precautionary action is needed now to avoid, to the extent possible, further tipping points being triggered.”
Climate Dominoes concludes that:
- At just 1.2°C of global average warming, tipping points have been passed for several large Earth systems. These include Arctic sea ice, the Greenland Ice Sheet, The Amundsen Sea glaciers in West Antarctica, the eastern Amazonian rainforest, and the world’s coral systems.
- System-level change is happening faster than forecast. In each case surveyed, abrupt change is happening earlier and/or faster than projected only two decades ago.
- Climate models don’t incorporate key processes and are not reliable. Climate models do not yet incorporate key processes, and therefore are deficient, especially when projecting abrupt change, system cascades, and changes in the cryosphere and in the carbon cycle.
- The Earth climate system is undergoing abrupt change. It is not just that individual elements of the climate system are tipping and/or changing rapidly. They also affect each other.
- Cascades and accelerated warming may trigger Hothouse conditions. These observed events are consistent with the cascade of system changes that may drive Earth past the “Hothouse Earth” threshold. This is not to say that this scenario is already locked into the system, but scientists have been warned that it may become active in the 1.5–2°C threshold, and that is where we are heading now, likely at an accelerated rate of warming over the next two decades.
- Risks have been underestimated. The risks are systemic, but quantifying the probability and severity of systemic risks is not possible due to their complex nature. Because abrupt system change is happening faster than forecast, we are ill-prepared for what may happen.
A recent conversation with Prof. John Moore confirmed the conclusions in Climate Dominoes. Moore is a glaciologist and professor at the Arctic Centre at the University of Lapland in Finland and Chief Scientist, College of Global Change and Earth System Science, Beijing Normal University. I asked Moore about various cryosphere tipping points and sea-level rises:
- On West Antarctica, Moore said it was not “particularly exaggerated to call [Thwaites] the ‘doomsday glacier’’’.
- Greenland: “There is no doubt that Greenland is not in equilibrium for the present climate and you would not need to change temperatures by very much for guaranteed or very rapid or extreme shrinking of the ice sheet, but it is a relatively slow process compared to Antarctica.”
- Himalayas and Tibetan Plateau: “These glaciers pretty much — two-thirds to three-quarters — will be gone this century even under reasonably optimistic scenarios… They are not able to maintain themselves in the current climate and will rapidly disappear in a future climate.”
- Sea levels: “When we look at the record (of sea-level rises) preserved in things like coral reefs, we can see five metres of sea-level rise in little more than a century, it is extremely worrying because the rates of sea-level rise that humans are experiencing and are used to are something like 20 cm in a hundred years.” I asked: “Are you confident that sea-level rise models now are taking into account what has been learned about Antarctica”. His answer: “I don’t think they do,”
The evidence in Climate Dominoes leads to one inescapable conclusion: Decarbonisation is not enough. Even sharp reductions in emissions will not be enough to avoid crossing the 1.5°C threshold, and very likely the 2°C threshold, given record-breaking use of fossil fuels in 2021 and the forecasts for 2022-24.
It is a big mistake to think we can “park” the Earth System at any given temperature rise – say 2°C – and expect it to stay there. 2°C may not be a point of system stability. Reducing the level of atmospheric carbon dioxide by carbon drawdown is vital, but the drawdown impact is relatively slow.
The more damaging impacts, and risk of triggering non-linear events — associated with a higher level of warming for several decades in overshoot scenarios — are understated or ignored. The need to cool the planet in order to avoid cascade/collapse/”Hothouse” scenarios needs to be taken seriously.
The evidence that numerous tipping points are already in play is now irrefutable, and that means we now need a serious conversation about how to mitigate them, including by climate interventions, also known as geoengineering.
Sir David King formed the Centre for Climate Repair at Cambridge in part to look at what sort of interventions might be feasible in preventing a cascade of events in the Arctic that would mean, put bluntly, that warming would spiral out of humans’ capacity to either mitigate it or adapt to it. In a foreword to a Breakthrough report in 2021, King outlined why :
“Today the level of greenhouse gases (GHGs) in the atmosphere is already so high that rapid emissions reduction is no longer sufficient to avoid an unmanageable future for mankind. We also must have the capability to remove GHGs at scale from the atmosphere, and to repair those parts of the climate system, such as the Arctic Circle, which are passing or have passed their tipping point. In recent years, as the scientific projections and the evidence have accumulated, concerned scientists and institutions have called for emergency action to address the climate change threat. These calls were picked up widely by communities worldwide in 2019, but are still largely unheeded by political and business leaders… It is the short term which matters most. What global leaders do in the next three-to-five years will determine the future of humanity.”
One research focus for the Centre for Climate Repair is whether marine cloud brightening (MCB) ) could help cool the Arctic and mitigate the risk of large-scale activation of permafrost carbon stores. Researchers have also been looking at the possible of MCB in lowering ocean heat content around the Great Barrier Reef.
Prof. John Moore has been inquiring about possible climate interventions to stabilise Antarctic glaciers. This work is now even more urgent given the research released in December 2021 about the Thwaites Glacier in West Antarctica, now referred to as the “doomsday” glacier, because the Thwaites ice shelf is likely to break apart in the next five years or so, resulting in a speeding up of the glacier’s flow and ice discharge, possibly heralding the collapse of the glacier itself, and triggering similar increases across the Amundsen Sea glaciers.
Moore says the only way of preventing the collapse of such glaciers is to physically stabilize the ice sheets because Thwaites is in a state of “geometric instability… there is a ball at the top of the hill and it has started to roll down, it doesn’t matter what the temperature is, the ball doesn’t care…”. In other words, even moderate cooling in Antarctica may not be enough to stop the process, and solar radiation management may not be effective in reducing ocean heat content.
Moore says that the big feature of ice loss from Antarctica “is the very rapid flow rate of ice through rather narrow channels [under the ice sheet] as the ice exits to the coast. At Thwaites the warm water that is coming from the southern ocean and connects to the rest of the world’s ocean system finds access under the ice shelf that is buttressing the inland ice through a channel that is only about four kilometres wide, so if you could do something about that warm water going under the glacier you would slow the melt rate dramatically, and immediately the ice shelf would start to thicken again and our hope is the you would get the system back to the early 20th century levels of melt rate and increase that buttressing effect by stopping this warm water going underneath the ice shelf.”
Moore and his colleagues are investigating the development of what they call a sea-bed anchored curtain, with a heavy foundation anchored into the sea floor, a little like ocean wind turbines or oil rig anchors:
“So we (already) have the technology to install these structures in water deeper than we are dealing with in Thwaites [and] this foundation is holding up a plastic curtain that is buoyant itself in the water and this would try to be upright but it would be pushed by the current, and it would be in sections that would allow it some robustness against things such as icebergs impacts so you could replace elements of it. It would act as a sort of natural sill… now these sills already exist. And we want something that is easy to remove in the case of unexpected side effects.”
[For more detail on sea-bed anchored curtains, see The radical intervention that might save the "doomsday" glacier and Glacier geoengineering to address sea-level rise: A geotechnical approach.]
Moore says that the aim would not be to hold the glacier back: “What we are talking about is slowing the amount of warm water that is melting the ice at the present rate. Something that would protect the vulnerable glaciers [in West Antarctica]... we think the capital cost would be something between 40 and 80 billion dollars, and one-to-two billion dollars a year on maintenance.”
I asked Moore about political buy-in for glacial engineering:
“You would want to gain engineering experience and understanding so would need to do tests that would not have to be in a glaciated area, [including] how durable are the materials. You could do those kinds of tests anywhere you have stratified flow. We are interested in seeing if the Greenlanders are interested in this, because we have a project funded by the Nordic Council of Ministers which is to go to Greenland and work with Greenlanders and co-design an intervention for the ice sheet … and talk to the locals and ask them if you could choose a configuration for the ice sheet, what would be best for you in terms of your ways of life, tourism, fisheries, those kinds of things that are very important to them. Because the ice is changing very rapidly and we expect the ice sheet will retreat maybe 50 kms over the next 50 years or so in the Ilulissat area, and that would have dramatic impacts on many of their ways of life. We want to try and empower them, in a sense with Greenland it is more about a local ecosystem service kind of approach rather than a global sea-level kind of approach.”
For Antarctica, the big question is whether any of the Antarctic partners act as if they have a duty of care to act in terms of the sort of proposals Moore and his colleagues are researching. Moore says:
“Short answer, no. People have fundamentally thought of Antarctica as a sort of place where we should keep hands off, whereas we are saying there is this duty of care to actively conserve the situation there because if we do nothing places like Thwaites will rapidly destabilise and that will fundamentally change the configuration of the ice sheet, the ecology on the sea bottom in the region and the animals and plants that live there will be impacted far more dramatically that what humans are doing by having a few research stations in Antarctica.”
Glacial engineering is a big challenge for those who are morally opposed to any thought of climate interventions, and emphasise climate justice. Sea-level rise from polar ice sheet loss will displace hundreds of millions of people and literally drown nations and cities and river deltas, and adaptation will include the organised displacement of most of those people, and efforts to compensate for the loss of some of the world's most valuable food-growing areas such as the Mekong Delta.
John Moore was clear about the moral choice: “It is a much more ethically sound position to conserve the ice sheets intact than to rely on adaptation around the global coastline,” he said.
- View the conversation with Prof. John Moore
