As we head into COP29 in oil-and-gas-rich Azerbaijan with the UN warning we are on course for up to 3°C of temperature rise, climate scientists are urging governments to focus on cryosphere. The frozen regions of our planet are warming several times faster than the global average. If the nations of the world cannot agree on measures to hold global warming to a maximum of 1.5°C, the experts warn of potentially devastating and irreversible impacts from cryosphere melt, not just for the icy north, but for the whole planet.
Icy temperatures making northern Europe uninhabitable, a breakdown of agriculture, fisheries disruption, unprecedented regional weather extremes, additional sea level rise with disastrous flooding – the Nordic Council of Ministers meeting in Reykjavik, Iceland, in October received a stark warning from 43 leading international climate scientists. In an open letter delivered by Professor Stefan Rahmstorf, Head of Earth System Analysis at Germany’s Potsdam Institute for Climate Impact Research, the experts warn that there is a “serious risk of a major ocean circulation change in the Atlantic, (…) with devastating and irreversible impacts, especially for Nordic countries, but also for other parts of the world”.
Icy prospects for northern Europe
The experts see growing evidence that the Atlantic Meridional Overturning Circulation (AMOC), the system of ocean currents that transports heat northwards into the North Atlantic, is increasingly at risk of passing a tipping point and eventually collapsing. AMOC, the scientists write, “determines life conditions for all people in the Arctic region and beyond”.
Remember that Hollywood film, “The Day after Tomorrow”, with the scenario of melting polar ice caps pouring fresh water into the oceans and diluting the salt level balance, causing the temperature of the ocean currents to plummet and disrupting the North Atlantic current? A Hollywood blockbuster: doom, rapid and sudden disaster, heroics, emotion and plenty of willing suspension of disbelief. But that basic idea of polar ice changing currents, warmth transport and disrupting the climate? Not as far-fetched as it might have seemed?
An influx of cold, fresh water from melting land ice like Greenland’s massive ice sheet, is a major factor in changing ocean currents, altering the temperature and salinity of the water.
There are indications that Amoc has been slowing down for the last 60 or 70 years due to global heating, Rahmstorf explains in an interview with the Guardian. The most ominous sign, he says, is the “cold blob” over the northern Atlantic.
“The region is the only place in the world that has cooled in the past 20 years or so, while everywhere else on the planet has warmed – a sign of reduced heat transport into that region, exactly what climate computer models have predicted in response to Amoc slowing as a result of greenhouse gas emissions.”
So why the outcry at this particular time?
When science overtakes itself
“A string of scientific studies in the past few years suggests that this risk has so far been greatly underestimated, the climate scientists write in their open letter. ”Such an ocean circulation change would have devastating and irreversible impacts especially for Nordic countries, but also for other parts of the world.”
The authors, from institutes all over the globe, say “science increasingly confirms that the Arctic region is a “ground zero” for tipping point risks and climate regulation across the planet.”
They warn: “In this region, the Greenland Ice Sheet, the Barents sea ice, the boreal permafrost systems, the subpolar gyre deep-water formation and AMOC are all vulnerable to major, interconnected nonlinear changes”.
The reports by the IPCC, the syntheses of our scientific knowledge on climate change, which should provide the basis for governments to act on climate, are unable to keep pace with ongoing research. The body allocates degrees of likelihood to possible changes in the climate system. The IPCC concluded in its last report that “there is medium confidence that the Atlantic Meridional Overturning Circulation will not collapse abruptly before 2100”. Now that might have reassured a lot of people, especially looking at a short-term perspective. “But if it were to occur, it would very likely cause abrupt shifts in regional weather patterns, and large impacts on ecosystems and human activities”, the report went on.
Now the 43 authors of the open letter, including high-profile scientists like Timothy Lenton, Anders Levermann, Michael Mann, Stefan Rahmstorf and Johan Rockström say recent research since the last IPCC report suggests the body has underestimated this risk, and that “the passing of this tipping point is a serious possibility already in the next few decades”.
Worrying?
A risk too high to ignore
The scientists stress that despite significant research into the possibility and mechanisms of a collapse, the probability of such an occurrence remains highly uncertain. But in their view, only“medium confidence” in the AMOC not collapsing “is not reassuring, and clearly leaves open the possibility of an AMOC collapse during this century. And there is even greater likelihood that a collapse is triggered this century but only fully plays out in the next”, they write.
It is a question of risk assessment, Rahmstorf told the Guardian:
“ I compare it to being told that there is a 10% chance of an airplane crashing. Would you get on that plane? I wouldn’t. The disastrous consequences are unacceptable.”
As for his own expectations: “I am now very concerned that we may push Amoc over this tipping point in the next decades. If you ask me my gut feeling, I would say the risk that we cross the tipping point this century is about 50/50”, Rahmstorf told the Guardian.
That is seriously worrying!
Insights from the distant past
A study just published in Nature by the iC3 Polar Research Hub based at UiT, the Arctic University of Norway in Tromsö, backs up the warning that melting Arctic sea ice could affect global ocean circulation by looking at what happened in Earth’s history. The researchers discovered that growing inflows of freshwater from melting Arctic sea-ice into the Nordic Seas “likely significantly affected ocean circulation, sending temperatures plummeting across northern Europe.”
Lead author Mohamed Ezat from the iC3 Polar Research Hub, told me in an email:
“While climate models provide valuable insights into what our future climate may look like, they still carry large uncertainties, in particular for long-term predictions and at regional scales. Looking at the distant past of the earth’s climate history in particular when it was warmer than today can reduce such uncertainties. For example, in our study we focused on the Last Interglacial period, some 128,000 years ago, when the global average temperature was estimated to be 1 to 2 C warmer than preindustrial i.e.it is like what we are heading to during this century.”
Ezat describes these findings as “alarming”: “This reminds us that the planet’s climate is a delicate balance, easily disrupted by changes in temperature and ice cover.”
Ice-free summer conditions are expected to occur in the Arctic Ocean from as early as the year 2050.
As I have discussed so many times on the Ice Blog, what happens in the High North affects the whole planet. As Ezat told me, based on his research:
“Changes in Arctic Sea ice can significantly impact the ocean ecosystems and resources at high latitudes. It also affects the climate globally. For example, and of particular relevance to our study, melting of Arctic sea ice may result in enhanced freshwater export into the Nordic Seas and the North Atlantic Ocean. This may slow down the Atlantic Meridional Overturning Circulation, which can ultimately lead to disruptions of the seasonal monsoons, reduced oceanic carbon dioxide uptake (and thus more CO2 accumulation in the atmosphere) and additional sea-level rise in some regions such as along the U.S. East coast.”
This fits with the warnings issued by the 43 scientists to the Nordic Council of Ministers.
“The impacts particularly on Nordic Countries would likely be catastrophic, including major cooling in the region while surrounding regions warm. This would be an enlargement and deepening of the ‘cold blob’ that already has developed over the subpolar Atlantic Ocean, and likely lead to unprecedented extreme weather. While the impacts on weather patterns, ecosystems and human activities warrant further study, they would potentially threaten the viability of agriculture in northwestern Europe”, the scientists explain.
Why COP29 must focus on the cryosphere
Scientists and concerned groups have long been highlighting the importance of cryosphere melt and trying to direct attention towards the impacts at the annual UN climate talks. The International Cryosphere Climate (ICCI) Initiative, which publishes the annual State of the Cryosphere Report, regularly organizes a Cryosphere Pavilion at the COP venue, bringing scientists, negotiators and policymakers together to put the spotlight on our frozen regions. Last year, the organisation published an open letter at COP28 by more than 1,000 scientists, calling for the Cover Decision to include the cryosphere issue:
“Because of the Cryosphere response, even 2°C is too high. The Paris Agreement’s “well below 2°C” can mean just one thing: 1.5°C alone. We therefore need a Stocktake with clear guidelines to make 1.5°C a reality; a path to phase out fossil fuels; and financial mechanisms to support climate action, as well as the adaptation, and loss and damage – most of it ultimately tied to irreversible Cryosphere loss – now inevitable even below 1.5°C; but far worse above that.
A failure to do so would mean “world leaders are de facto deciding to burden humanity for centuries to millennia by displacing hundreds of millions of people from flooding coastal settlements; depriving societies of life-giving freshwater resources, disrupting delicately-balanced polar ocean and mountain ecosystems; and forcing future generations to offset long-term permafrost emissions.”
Sadly, the Dubai COP28 did not produce the desired results:
With each passing year, the need for climate action becomes more urgent, the window for averting catastrophic impacts closes further. At COP29 in Baku, we still have another chance.
ICCI will publish the 2024 State of the Cryosphere Report,in the coming weeks. It is unlikely to bring any respite, I fear. The organisation is also one of 8 partners joining Norway, the current Chair of the Arctic Council, to host a major side event at COP29 entitled “A message from the Frozen World – the Global Impact of a Changing Cryosphere”. Politicians, scientists and Indigenous representatives will aim to “bring the cryosphere to COP29”, as part of a concerted effort to bridge the gap between science on the one hand and policy and governance on the other.
“For too long, the cryosphere has been left off the global climate agenda despite its immense impacts. As Chair of the Arctic Council, Norway is determined to bring this critical issue to the forefront, convening key actors and driving action. Norway is committed to elevating the cryosphere on the global agenda, ensuring the world hears the urgent message from the polar and high mountains region and takes decisive action,” the Arctic Council writes.
Sounds good? High time, given Norway’s location in the High North – and the country’s background as a fossil-fuel economy.
Cryosphere threat: too long ignored
Glaciers and ice sheets, snow, permafrost and sea ice all bind us together by supplying fresh water to millions of people, stabilizing the global climate, and protecting us from sea-level rise, the organizers write.“However, the cryosphere is under significant threat from various climate change-driven factors, and the world cannot look away”. They make the link between the Arctic and other cryosphere regions such as the Himalayas, and other parts of the world which will be affected by change in distant frozen regions.
“These changes are speeding up at an unprecedented rate and impacting people everywhere. (…) Sea-level rise from ice sheets and glaciers is flooding low-lying coastal areas and causing erosion, putting hundreds of millions of people in coastal cities and island communities at risk in coming decades. Mountain glaciers, which provide freshwater to millions of people, are melting rapidly, and snowpack is decreasing. This is leading to increased flooding and contamination of water sources, which threatens the supply of reliable freshwater to billions of people. Thawing permafrost is causing severe damage to buildings and infrastructure across the Arctic, Himalayas and other mountain regions. The changing cryosphere is also threatening homes and livelihoods, often impacting Indigenous Peoples such as the Saami, Inuit and Sherpa who also face a multitude of external compounding threats. It is also opening travel to and through the Arctic, leading to increased activity in areas such as shipping and mining exploration.”
The side event, with high-ranking politicians, scientists and Indigenous representatives, “not only integrates comprehensive insights from local to global scales but also transitions smoothly into actionable steps guided by the latest scientific research and policy frameworks, aiming to catalyze decisive global actions to reduce greenhouse gas emissions and short-lived climate forcers to limit global warming to 1.5°C. “
That, I would say, is official-speak for finally getting the message across to the world’s governments that they need to increase their efforts massively and come up with definitive measures to hold global warming to 1.5°C.
The level of warming increases the severity of impacts
In its 2023 Synthesis Report, the IPCC expresses “high confidence that the likelihood of irreversible changes in the climate system will increase with the level of global warming”. It also explains that the likelihood of potentially massive negative impacts increases with the level of warming.
Given that this is a body whose reports are subject to a rigorous editing process including pressure from governments to avoid anything that could be construed as panic-making or force them to take rapid measures they don’t want to take, that is a pretty strong statement.
As the scientists point out to the Nordic ministers, the IPCC actually writes that “risks associated with large-scale singular events or tipping points… transition to high risk between 1.5°C – 2.5°C of global warming”.
How much more do we need? Why has this not set the alarm bells ringing? The world’s experts have been telling us that even within the Paris Agreement limits of 2°C, preferably 1.5°C, we are risking catastrophic impacts across the globe, and that the risk gets higher with every bit of warming.
Emissions Gap – Rhetoric and Reality
The United Nations Environment Program (UNEP) has just published its Emissions Gap Report 2024 (sub-titled: No more hot air … please!). You could be forgiven if you missed it, as it was pushed onto the media sidelines by ongoing crises in the Middle East and Ukraine and the US election (whose outcome admittedly will to a large extent determine the fate of our climate).
The report identifies a “massive gap between rhetoric and reality” as countries draft their new climate commitments, to be presented early in 2025, while climate impacts intensify around the globe. “Nations must deliver dramatically stronger ambition and action in the next round of Nationally Determined Contributions or the Paris Agreement’s 1.5°C goal will be gone within a few years”, the UN finds.
Continuation of current policies will lead to a catastrophic temperature rise of up to 3.1°C, the report concludes.
Talk about scary?
Current commitments for 2030 are not being met; even if they are met, temperature rise would only be limited to 2.6-2.8°C.
Nations must collectively commit to cutting 42 per cent off annual greenhouse gas emissions by 2030 and 57 percent by 2025 in the next round of Nationally Determined Contributions (NDCs) – and back this up with rapid action.
Otherwise, the world on course for a temperature increase of 2.6-3.1°C over the course of this century. This would bring “debilitating impacts to people, planet and economies”, UNEP states. That could be putting it mildly.
Trying to look on the positive side, “It is still technically possible to meet the 1.5°C goal, but only with a G20-led massive global mobilization to cut all greenhouse gas emissions, starting today”, the report finds.
Ice and snow melt: no better reason for immediate climate action
What is happening in the cryosphere should convince even the most reluctant of the need to reduce emissions drastically asap.
Let us come back to the plea for action presented by those 43 climate scientists to the Nordic Council of Ministers. That group includes Arctic Council Chair Norway – self-declared champion of the cryosphere at COP29 – and Iceland, a co-organiser of the COP29 cryosphere event and co-chair of the Ambition on Melting Ice (AMI) group founded by 20 government ministers in 2022 at COP27 in Sharm El-Sheikh, Egypt. (Norway is also a member). AMI aims to “ensure that the irreversible and devastating global impacts of cryosphere loss are understood by political leaders and the public alike: not only within mountain and polar regions, but throughout the planet.”
The scientists’ message to the political leaders:
“Given the increasing evidence for a higher risk of an AMOC collapse, we believe it is of critical importance that Arctic tipping point risks, in particular the AMOC risk, are taken seriously in governance and policy. Even with a medium likelihood of occurrence, given that the outcome would be catastrophic and impacting the entire world for centuries to come, we believe more needs to be done to minimize this risk”. And they stress that the northern governments could champion the cause.
For Norway, in particular, (and my native Scotland), Rahmstorf says in an interview with the Guardian:
“The risks will be existential and raise the question whether people can continue to live there or whether most of them would rather move”.
The conclusion should be obvious, Rahmstorf goes on:
“This is all driven mainly by fossil fuel emissions and also deforestation, so both must be stopped. We must stick to the Paris agreement and limit global heating as close to 1.5C as possible.”
The scientist adds:
“ I don’t think it is my job to talk about my feelings, but I do have two children and I am very worried about what future they will live in. I sometimes joke that physicists don’t have feelings. But even physicists care about their kids”.
With a concerted effort, this could and should be the UN conference where the cryosphere, our frozen world, finally makes it to the top of the international climate agenda. The reasons for that are not happy ones. But there will be no action without awareness. And a lack of action – fast, definitive, effective – would spell disaster.
