A new risk analysis has found that the tipping points of five of Earth’s subsystems — the West Antarctic Ice Sheet, the Greenland Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), the El Niño–Southern Oscillation (ENSO) and the Amazon rainforest — could interact with each other in a destabilizing manner.
It suggests that these changes could occur even before temperatures reach 2°C (3.6°F) above pre-industrial levels, which is the upper limit of the Paris Agreement.
The interactions between the different tipping elements could also lower critical temperature thresholds, essentially allowing tipping cascades to occur earlier than expected, according to the research.
Experts not involved in the study say the findings are a significant contribution to the field, but do not adequately address the timescales over which these changes could occur.
When the first tile in a line of dominoes tips forward, it affects everything in front of it. One after another, lined-up dominoes knock into each other and topple. This is essentially what could happen to ice sheets, ocean currents and even the Amazon biome if critical tipping points are crossed, according to a new risk analysis. The destabilization of one element could impact the others, creating a domino effect of drastic changes that could move the Earth into an unfamiliar state — one potentially dangerous to the future of humanity and nature as we know it.
The study, published this month in Earth System Dynamics, examines the interactions between five subsystems that are known to have vital thresholds, or tipping points, that could trigger irreversible changes. They include the West Antarctic Ice Sheet, the Greenland Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), the El Niño–Southern Oscillation (ENSO) and the Amazon Rainforest.
Scientists believe the AMOC could reach its critical threshold when warming temperatures weaken the current enough to substantially slow it, halt it, or redirect it, which could plunge parts of the northern hemisphere into a period of record cold, even as global warming continues elsewhere. Likewise, the Antarctic ice sheet may reach its irreversible threshold when warming temperatures trigger a state of constant ice loss, which could ultimately result in a 4-meter (13-foot) rise in global sea levels over the coming centuries. In fact, it’s suggested that the West Antarctic Ice Sheet may have already passed its critical threshold, and that ice loss is unstoppable now.
Interactions between climate tipping elements and their roles in tipping cascades. Image by Wunderling et al.
These individual tipping points are largely being driven by human-caused climate change, which is considered to be one of nine planetary boundaries — scientifically identified limits on change to vital Earth systems that currently regulate and sustain life. Overshooting those boundaries could lead to new natural paradigms catastrophic for humanity. Climate change has its own threshold of 350 parts per million (ppm) of CO2, which is the amount that scientists say the atmosphere can safely hold, but this threshold was already passed in 1988. In 2021, CO2 exceeded 417 ppm, which is 50% higher than pre-industrial levels.
To conduct this new study, the research team used a conceptual modeling process to analyze the interactions between these five Earth subsystems. What they found was that more than a third of these elements showed “tipping cascades” even before temperatures reached 2° Celsius (3.6° Fahrenheit) above pre-industrial levels, which is the upper limit of the 2015 Paris climate agreement. At present, almost no nation on Earth is on target to meet its Paris carbon reduction goals.
Significantly, the study also found that the interactions between the tipping elements could lower critical temperature thresholds, essentially allowing tipping cascades to occur earlier than anticipated. Additionally, the researchers found that the Greenland Ice Sheet would function as an initiator of tipping cascades, while the AMOC would act as a transmitter that would push further changes, including dieback of the Amazon. Most of these tipping elements have been projected to have a destabilizing effect on each other, with the exception of the weakening of the AMOC, which could actually make the North Atlantic region colder and help stabilize the Greenland Ice Sheet.
Canoe in the Zacambu river, Peru. Photo by Rhett A. Butler for Mongabay.
“We found that the overall interactions tend to make [things] worse, so to say, and tend to be destabilizing,” lead author Nico Wunderling, a scientist at the Potsdam Institute for Climate Impact Research in Germany, told Mongabay.
He said that the findings suggest that we already face significant risk, but that the study does not necessarily provide a forecast.
“We have made a risk analysis,” Wunderling said. “This is not a prediction, but it’s more like, ‘OK, if we have this warming, then we might face an increasing risk of tipping cascades.’”
Tim Lenton, a professor of climate change and Earth system science at the University of Exeter, U.K., and co-author of a similar study on tipping points, says the new paper is a “useful addition to the assessment of climate tipping point interactions.”
“The important takeaway message from this study is that the cascading causal interactions between four different climate tipping elements lower the ‘safe’ temperature level at which the risk of triggering tipping points is minimized,” Lenton told Mongabay in an email. “In fact the study suggests that below 2C of global warming (above pre-industrial) — i.e. in the Paris agreement target range — there could still be a significant risk of triggering cascading climate tipping points.”
However, Lenton says the study does not unpack the timescale in which these tipping cascades would occur, focusing more on their consequences.
Iceberg off Antarctica. Image by Mongabay.
“In the case of ice sheet collapse this can take many centuries,” he said. “Hence the results should be viewed as ‘commitments’ to potentially irreversible changes and cascades that we may be making soon, but will leave as a grim legacy to future generations to feel their full impact.”
Juan Rocha, an ecologist at the Stockholm Resilience Centre, says the findings of the study affirm previous hypotheses about how “the tipping of one system can affect the likelihood of others in a self-amplifying way,” although he also notes its oversight of evaluating timescales.
“The Amazon is likely to tip way earlier than AMOC or Greenland,” Rocha told Mongabay. “Future work needs to take into account the diversity and uncertainty of the feedbacks at play for each tipping element to really understand how likely [it] is that one system can tip the other.”
Rocha says he’s pleased the authors undertook this study and hopes others continue to build on this research.
“I would like to extend an invitation to the authors and the scientific community to keep working on these important questions,” he said. “There is a lot of work to do, a lot that we do not know, and our models can only get us so far. Understanding how different systems of the Earth … are connected is fundamental to avoid the risk of domino effects, but also to empower people to act on time, identify leverage points and understand the extent of action or lack of it.”
Citations:
Cai, Y., Lenton, T. M., & Lontzek, T. S. (2016). Risk of multiple interacting tipping points should encourage rapid CO2 emission reduction. Nature Climate Change, 6(5), 520-525. doi:10.1038/nclimate2964
Wunderling, N., Donges, J. F., Kurths, J., & Winkelmann, R. (2020). Interacting tipping elements increase risk of climate domino effects under global warming. Earth System Dynamics, 12, 601-619. doi:10.5194/esd-12-601-2021
Elizabeth Claire Alberts is a staff writer for Mongabay. Follow her on Twitter @ECAlberts.
Editor’s note: While it’s true that “it is the profit machine that is polluting our atmosphere, warming our planet, and destroying our ecosystems”, the real root of human destructiveness lies further back in history, when groups of people started agriculture, building cities and forming human supremist ideologies that disconnected human cultures from all other living beings.
We thought climate catastrophe the main danger. Now we know there is another. A double-whammy ecological crisis threatens collapse into dystopian chaos.
“Pathogens, a great and terrible global threat to human and many a non-human alike, [are] as much a Sword of Damocles hovering above civilisation as climate change.”
Evolutionary epidemiologist Rob Wallace wrote this in 2015. But he and many colleagues have been issuing increasingly urgent warnings since the 1990s that globalised agribusiness is breeding and spreading new, deadly, fast-transmission viruses.
The urgency around pandemics began to ramp up around the same time calls for climate action became mainstream. Many of us have been focused on the climate emergency – and nothing here should be taken to imply we were wrong – but the last year has taught a sharp lesson: deadly pathogens pose an equally menacing threat to human civilisation.
Catastrophe
Since the first United Nations COP conference on global warming in 1995, the climate emergency has got much worse. Carbon emissions have accelerated from 26 billion tonnes in 1995 to 37 billion tonnes in 2018. Atmospheric concentrations have risen from 350ppm in 1990 to 410ppm today. Half the increase in average global temperatures since the Industrial Revolution has occurred since 1995. The average volume of Arctic sea-ice has roughly halved in the last 40 years. Whatever the metric, the same story.
The effects are all around us. More frequent and more intense heat-waves are causing increases in wildfires, droughts, and desertification. Rising and warming seas are causing heavier rainfall, more serious flooding, more frequent mega-storms, and the inundation of coastal areas. These changes are driving the world’s sixth mass extinction, with species loss running at 1,000 times the normal rate. Climate change is destroying livelihoods, increasing disease, displacing people.
We stand on the brink of critical tipping-points when incremental shifts lead to sudden and irreversible lurches in the Earth’s ecosystem. Among the potential tipping-points are: abrupt collapse of the West Antarctic ice-sheet; abrupt collapse of the East Antarctic ice-sheet; abrupt collapse of the Greenland ice-sheet; thawing of Arctic permafrost and release of methane gas; rapid deforestation of the Amazon; and failure of the Atlantic Gulf Stream. Some scientists fear a ‘global cascade’ of interacting tipping-points.
The failure of the global political elite is systemic. It is not that we do not know what to do. It is not that the wrong policies have been adopted. It is that the economic and geopolitical system – the current world order – cannot deliver the radical action necessary.
The OECD (Organisation for Economic Co-operation and Development), representing the world’s leading industrial economies, considered the pre-pandemic global growth rate of three percent to have been too low. Yet such annual growth rate means a doubling in the size of the world economy every quarter century.
The fossil-fuel corporations plan to extract twice the amount of coal, oil, and gas between now and 2030 than can be burned if we are to restrict global temperature rise to the 1.5ºC ‘aim’ of the Paris Agreement.
This ‘aim’ is not ambitious enough: most climate scientists predict severe damage to the Earth’s eco-system with this level of warming. But even this ‘aim’ falls well below the ‘pledges’ of the COP participants, which, even if implemented, are expected to result in a disastrous 3ºC of global warming. Many leading scientists think we are heading for at least 4ºC of global warming.
Metabolic
The term ‘metabolic rift’ has been used by some radical commentators, like John Bellamy Foster, to describe what is happening. I prefer ‘rupture’ because it better captures the violence of a corporate capitalist system that is out of control and tearing apart human societies and natural ecosystems.
Metabolism is a scientific word to do with how chemical changes reconfigure energy and sustain life. All of us need to get science-wise, to understand what is happening to our planet, to get a handle on what I am calling the ‘Dual Metabolic Rupture’.
Humans are part of Nature. On the one hand, we are animals with material needs and organic form. On the other, our actions impact upon the rest of Nature, sometimes degrading it, sometimes remodelling it, always having an effect.
All the products of human labour are therefore part of Nature. Everything we do to provide ourselves with a livelihood involves drawing upon the resources of Nature and refashioning them into new forms.
These processes are not reversible, but they may be repeatable. If a glacier melts because the temperature rises, the water of which it is formed flows away. If a new glacier forms in the same place when the temperature falls again, it must be comprised of another body of water. In Nature, as in Society, everything is process and motion.
The energy involved in natural processes is a constant: it can be endlessly recycled, but it cannot be destroyed, so whatever you do, it will still be there in one form or another. This is one of the basic laws of physics (known as ‘the First Law of Thermodynamics’).
It follows that human beings may interact with Nature in ways that are ‘renewable’ or ‘sustainable’ – where energy is recycled in essentially repetitive ways – or in other ways that cause a metabolic ‘rupture’ or ‘rift’ – where energy is reconstituted as a destructive force.
Let us take two contrasting examples. A hoe-cultivator who harvests a garden plot of cassava, feeds the tubers and leaves to her pigs, and then lets them roam to manure the plot, is engaged in a recycling of energy that is ecologically sustainable.
Corporations that extract oil, refine it into petroleum, and then sell it to other corporations to burn in jet engines are doing something quite different: theirs is not a renewable process, but a release of carbon waste into the atmosphere and a permanent remodelling of the Earth’s metabolism.
The basic rhythms of pre-capitalist societies were determined by the cycle of the seasons. But capitalism is a system of competitive capital accumulation hard-wired by the profit motive for exponential growth.
The former were always essentially local or regional, so that what happened in one place had limited impact in others: the latter is now a fully globalised system which has the whole of humanity and the entire global environment in its grasp.
In the end, it is simple: it is the profit machine that is polluting our atmosphere, warming our planet, and destroying our ecosystems.
But that’s not all it’s doing.
Anthropocene
The system – let’s define it: globalised, financialised monopoly-capitalism – is blind to everything except the balance sheet, the bottom line, the annual profit.
The lords of capital have turned the Earth – its lands, its waters, its minerals – into private property. They have commodified its ecosystems and appropriated its bounty. And in their wake they spew waste and pollution that become ‘externalities’ for which others must pay.
Where to start? The catalogue of devastation is so long. Forests are cut down, wetlands drained, soils eroded. Water extraction turns farmland into desert. Chemicals are dumped in oceans, lakes, and rivers. Toxins leak into groundwater. Fertilisers, herbicides, and pesticides contaminate food supplies.
Landfills overflow with synthetic waste. Nuclear power plants melt down and fill air, land, and sea with carcinogenic particles. A chemical smog fills urban streets and poisons children on the way to school. Plastic waste degrades into trillions of microscopic specks that infect every living organism.
Now, from deep within this mayhem, a second titan of destruction has emerged to stand alongside the mega-threat of climate change: pandemic disease.
Both titans are formed of trillions of tiny particles. Climate change is driven by atoms of carbon dioxide – tiny particles of dead organic matter pumped into the atmosphere when fossil fuels are burned. Pandemic disease is driven by microscopic parasites – tiny particles of living organic matter that breed, spread, and evolve by infecting the bodies of animals.
But that does not mean Covid-19 is a natural disaster, any more than carbon pollution. Nor is it an Act of God or a ‘Chinese’ conspiracy. Covid is a human-made catastrophe, as much an artefact of the Anthropocene as global warming.
I agree with colleagues who argue that the Holocene is over. This is the term we have used to describe the last 11,700 years of Earth history, since the end of the last Ice Age – until now. From around 1950, and at an accelerating rate since, the Earth system has been undergoing radical change as a result of human action. We have entered a new geological era in which Anthropos (the Greek word for human) is the primary agent of change. The primary form of change is metabolic rupture.
Covid-19 is a pandemic disease of the Anthropocene’s metabolic rupture.
Pandemic
Mainstream commentary on the pandemic is refracted through a neoliberal prism. Attention focuses on immediate problems and proximate causes. I am not talking about serial liars like Johnson and his third-rate cabinet of public-school toffs and corporate spivs. I am talking about more honest commentators keen to see through the spin and smoke-cloud that shields a corrupt and incompetent political class.
But it is not enough to expose the negligence, crony capitalism, and eugenicist experiments of the Tories – the failure of test-and-trace, the lack of PPE, the locking down too late and lifting too early, the discharging of the sick into care homes, the spreading of the virus in schools and universities, and so much more.
It is necessary, but not enough. The narcissistic charlatan who runs the government might eventually be thrown out. But so what? There is a much bigger issue: the metabolic rupture between corporate agribusiness and natural ecology that has created the multiple global incubators of new deadly diseases.
In 1950, a large proportion of the Earth’s people were peasant farmers, predominantly in the Global South. As recently as 1980, only 20 percent of China’s population was urban; the proportion today is 60 percent. A growing number of those who remain in the villages, moreover, have been transformed into wage-labourers.
The advance of corporate agribusiness is relentless. As I write, the Hindu-chauvinist regime of Narendra Modi is facing an uprising of small farmers whose livelihoods are threatened with destruction by neoliberal ‘reform’. So desperate is their plight that record numbers of India’s small farmers have been committing suicide.
As well as destroying traditional communities, agribusiness is expanding into the wilderness, uprooting forests, destroying the diversity and balance of natural ecologies, and replacing them with vast monocultures. Half the habitable surface of the Earth is now devoted to agriculture, with millions of acres added every year.
Much of the crop-land produces animal feed for the hundreds of millions of cattle, sheep, pigs, and poultry being fast-fattened for the global supply-chains that loop the world. The mega-complexes of Big Farm’s industrialised animal production are laced around and between the mega-slums of the Global South’s ever-growing urban proletariat.
This is what links a remote bat-cave in hinterland China with the morgues of New York and London. Big Farm batters down natural ecology, destroying diversity and firebreaks. Viruses that would have burnt themselves out in the forest for lack of carriers adapt to a new ecology of monoculture, animal factories, and slum cities; they mutate and evolve and then achieve fast-track transmission through mass concentrations of the same species.
The global supply-chains of giant transnationals with operations in half a dozen countries and markets in a thousand cities do the rest.
Once a new variant is established, it replicates by the trillion at hyper-speed, throwing up chance mutations, testing new ways of spreading. The disease becomes endemic and chronic – embedded in human society – and continues to evolve, waging a relentless life-or-death struggle against lockdowns and vaccines by constant shape-sifting in its efforts to breach the defences.
Warning
This – the pandemic diseases created and spread by corporate agribusiness – is then layered over societies mired in poverty and stripped of public health-provision by neoliberal ‘structural adjustment programmes’, privatisation, and austerity cuts.
The epidemiologists have been warning of the dangers for a quarter of a century. There have been dozens of outbreaks of different viruses or variants, all involving a similar basic mechanism: the introduction of a wild-animal virus, its transmission and evolution through factory-farm complexes, a jump from animal to human, often in mutant form, and rapid global spread through transnational supply-chains.
The warning, endlessly repeated, was that, sooner or later, one of the new diseases created by neoliberal capitalism would take off. But there is no profit in pandemic precaution.
The improvised plague cemeteries; the body-bags in the morgues; the patients breathing through ventilators; the traumatised and exhausted health workers; the everyday folk left grieving; the jobs lost, businesses gone bust, homes lost to the bailiffs; the swelling toll of mental breakdowns; the loneliness, the shrivelled lives, the sense of desolation and despair: all this and more amount to so many ‘externalities’ for the profit machine.
The machine carries on. It is being recalibrated. Some businesses may be shutting down, but big capital is highly mobile. The money moves at click-key speed. It flows from a place where profits are down to another where they are up.
America’s 660 billionaires, for example, are doing just fine right now. Since March last year, their wealth has increased 39 percent, from just under $3 trillion to more than $4 trillion today. It is the rest of us, of course, who pay for the system’s ‘externalities’.
Those ‘externalities’ now take the form of a Dual Metabolic Rupture between humanity and the planet, as industrial pollution destroys our ecosystem, and agribusiness generates wave after wave of killer pathogen. We are the inhabitants of a new geological age – the Anthropocene – in which globalised, financialised monopoly-capitalism has become an existential threat to life on Earth.
What happens next depends on what we do. The imperative to get active has never been greater.
While U.S. Secretary of State Antony Blinken draws attention to climate change in the Arctic at meetings with other national officials this week in Iceland, an even greater threat looms on the other side of the planet.
New research shows it is Antarctica that may force a reckoning between the choices countries make today about greenhouse gas emissions and the future survival of their coastlines and coastal cities, from New York to Shanghai.
That reckoning may come much sooner than people realize.
Scientists have long known that the Antarctic ice sheet has physical tipping points, beyond which ice loss can accelerate out of control. The new study, published in the journal Nature, finds that the Antarctica ice sheet could reach a critical tipping point in a few decades, when today’s elementary school kids are raising their families.
The results mean a common argument for not reducing greenhouse gas emissions now – that future technological advancement can save us later – is likely to fail.
A satellite image shows the long flow lines as a glacier moves ice into Antarctica’s Ross Ice Shelf, on the right. The red patches mark bedrock. USGS
The new study shows that if emissions continue at their current pace, by about 2060 the Antarctic ice sheet will have crossed a critical threshold and committed the world to sea level rise that is not reversible on human timescales. Pulling carbon dioxide out of the air at that point won’t stop the ice loss, it shows, and by 2100, sea level could be rising more than 10 times faster than today.
The tipping point
Antarctica has several protective ice shelves that fan out into the ocean ahead of the continent’s constantly flowing glaciers, slowing the land-based glaciers’ flow to the sea. But those shelves can thin and break up as warmer water moves in under them.
As ice shelves break up, that can expose towering ice cliffs that may not be able to stand on their own.
There are two potential instabilities at this point. Parts of the Antarctic ice sheet are grounded below sea level on bedrock that slopes inward toward the center of the continent, so warming ocean water can eat around their lower edges, destabilizing them and causing them to retreat downslope rapidly. Above the water, surface melting and rain can open fractures in the ice.
The study used computer modeling based on the physics of ice sheets and found that above 2 C (3.6 F) of warming, Antarctica will see a sharp jump in ice loss, triggered by the rapid loss of ice through the massive Thwaites Glacier. This glacier drains an area the size of Florida or Britain and is the focus of intense study by U.S. and U.K. scientists.
Other projections don’t account for ice cliff instability and generally arrive at lower estimates for the rate of sea level rise. While much of the press coverage that followed the new paper’s release focused on differences between these two approaches, both reach the same fundamental conclusions: The magnitude of sea level rise can be drastically reduced by meeting the Paris Agreement targets, and physical instabilities in the Antarctic ice sheet can lead to rapid acceleration in sea level rise.
The disaster doesn’t stop in 2100
The new study, led by Robert DeConto, David Pollard and Richard Alley, is one of the few that looks beyond this century. One of us is a co-author.
It shows that if today’s high emissions continued unabated through 2100, sea level rise would explode, exceeding 2.3 inches (6 cm) per year by 2150. By 2300, sea level would be 10 times higher than it is expected to be if countries meet the Paris Agreement goals. A warmer and softer ice sheet and a warming ocean holding its heat for centuries all prevent refreezing of Antarctica’s protective ice shelves, leading to a very different world.
The vast majority of the pathways for meeting the Paris Agreement expect emissions will overshoot its goals of keeping warming under 1.5 C (2.7 F) or 2 C (3.6 F), and then count on future advances in technology to remove enough carbon dioxide from the air later to lower the temperature again. The rest require a 50% cut in emissions globally by 2030.
Although a majority of countries – including the U.S., U.K. and European Union – have set that as a goal, current policies globally would result in just a 1% reduction by 2030.
It’s all about reducing emissions quickly
Some other researchers suggest that ice cliffs in Antarctica might not collapse as quickly as those in Greenland. But given their size and current rates of warming – far faster than in the historic record – what if they instead collapse more quickly?
Second, allowing global warming to overshoot 2 C is not a realistic option for coastal communities or the global economy. The comforting prospect of technological fixes allowing a later return to normal is an illusion that will leave coastlines under many feet of water, with devastating economic impacts.
Third, policies today must take the long view, because they can have irreversible impacts for Antarctica’s ice and the world. Over the past decades, much of the focus on rapid climate change has been on the Arctic and its rich tapestry of Indigenous cultures and ecosystems that are under threat.
As scientists learn more about Antarctica, it is becoming clear that it is this continent – with no permanent human presence at all – that will determine the state of the planet where today’s children and their children will live.
In this article, originally published on The Conversation, three scientists argue that the concept of net zero which is heavily relying on carbon capture and storage technologies is a dangerous illusion.
By James Dyke, Senior Lecturer in Global Systems, University of Exeter, Robert Watson, Emeritus Professor in Environmental Sciences, University of East Anglia, and Wolfgang Knorr, Senior Research Scientist, Physical Geography and Ecosystem Science, Lund University
Sometimes realisation comes in a blinding flash. Blurred outlines snap into shape and suddenly it all makes sense. Underneath such revelations is typically a much slower-dawning process. Doubts at the back of the mind grow. The sense of confusion that things cannot be made to fit together increases until something clicks. Or perhaps snaps.
Collectively we three authors of this article must have spent more than 80 years thinking about climate change. Why has it taken us so long to speak out about the obvious dangers of the concept of net zero? In our defence, the premise of net zero is deceptively simple – and we admit that it deceived us.
The threats of climate change are the direct result of there being too much carbon dioxide in the atmosphere. So it follows that we must stop emitting more and even remove some of it. This idea is central to the world’s current plan to avoid catastrophe. In fact, there are many suggestions as to how to actually do this, from mass tree planting, to high tech direct air capture devices that suck out carbon dioxide from the air.
The current consensus is that if we deploy these and other so-called “carbon dioxide removal” techniques at the same time as reducing our burning of fossil fuels, we can more rapidly halt global warming. Hopefully around the middle of this century we will achieve “net zero”. This is the point at which any residual emissions of greenhouse gases are balanced by technologies removing them from the atmosphere.
This is a great idea, in principle. Unfortunately, in practice it helps perpetuate a belief in technological salvation and diminishes the sense of urgency surrounding the need to curb emissions now.
We have arrived at the painful realisation that the idea of net zero has licensed a recklessly cavalier “burn now, pay later” approach which has seen carbon emissions continue to soar. It has also hastened the destruction of the natural world by increasing deforestation today, and greatly increases the risk of further devastation in the future.
To understand how this has happened, how humanity has gambled its civilisation on no more than promises of future solutions, we must return to the late 1980s, when climate change broke out onto the international stage.
Steps towards net zero
On June 22 1988, James Hansen was the administrator of Nasa’s Goddard Institute for Space Studies, a prestigious appointment but someone largely unknown outside of academia.
By the afternoon of the 23rd he was well on the way to becoming the world’s most famous climate scientist. This was as a direct result of his testimony to the US congress, when he forensically presented the evidence that the Earth’s climate was warming and that humans were the primary cause: “The greenhouse effect has been detected, and it is changing our climate now.”
If we had acted on Hansen’s testimony at the time, we would have been able to decarbonise our societies at a rate of around 2% a year in order to give us about a two-in-three chance of limiting warming to no more than 1.5°C. It would have been a huge challenge, but the main task at that time would have been to simply stop the accelerating use of fossil fuels while fairly sharing out future emissions.
Four years later, there were glimmers of hope that this would be possible. During the 1992 Earth Summit in Rio, all nations agreed to stabilise concentrations of greenhouse gases to ensure that they did not produce dangerous interference with the climate. The 1997 Kyoto Summit attempted to start to put that goal into practice. But as the years passed, the initial task of keeping us safe became increasingly harder given the continual increase in fossil fuel use.
It was around that time that the first computer models linking greenhouse gas emissions to impacts on different sectors of the economy were developed. These hybrid climate-economic models are known as Integrated Assessment Models. They allowed modellers to link economic activity to the climate by, for example, exploring how changes in investments and technology could lead to changes in greenhouse gas emissions.
They seemed like a miracle: you could try out policies on a computer screen before implementing them, saving humanity costly experimentation. They rapidly emerged to become key guidance for climate policy. A primacy they maintain to this day.
Unfortunately, they also removed the need for deep critical thinking. Such models represent society as a web of idealised, emotionless buyers and sellers and thus ignore complex social and political realities, or even the impacts of climate change itself. Their implicit promise is that market-based approaches will always work. This meant that discussions about policies were limited to those most convenient to politicians: incremental changes to legislation and taxes.
Around the time they were first developed, efforts were being made to secure US action on the climate by allowing it to count carbon sinks of the country’s forests. The US argued that if it managed its forests well, it would be able to store a large amount of carbon in trees and soil which should be subtracted from its obligations to limit the burning of coal, oil and gas. In the end, the US largely got its way. Ironically, the concessions were all in vain, since the US senate never ratified the agreement.
Postulating a future with more trees could in effect offset the burning of coal, oil and gas now. As models could easily churn out numbers that saw atmospheric carbon dioxide go as low as one wanted, ever more sophisticated scenarios could be explored which reduced the perceived urgency to reduce fossil fuel use. By including carbon sinks in climate-economic models, a Pandora’s box had been opened.
It’s here we find the genesis of today’s net zero policies.
That said, most attention in the mid-1990s was focused on increasing energy efficiency and energy switching (such as the UK’s move from coal to gas) and the potential of nuclear energy to deliver large amounts of carbon-free electricity. The hope was that such innovations would quickly reverse increases in fossil fuel emissions.
But by around the turn of the new millennium it was clear that such hopes were unfounded. Given their core assumption of incremental change, it was becoming more and more difficult for economic-climate models to find viable pathways to avoid dangerous climate change. In response, the models began to include more and more examples of carbon capture and storage, a technology that could remove the carbon dioxide from coal-fired power stations and then store the captured carbon deep underground indefinitely.
This had been shown to be possible in principle: compressed carbon dioxide had been separated from fossil gas and then injected underground in a number of projects since the 1970s. These Enhanced Oil Recovery schemes were designed to force gases into oil wells in order to push oil towards drilling rigs and so allow more to be recovered – oil that would later be burnt, releasing even more carbon dioxide into the atmosphere.
Carbon capture and storage offered the twist that instead of using the carbon dioxide to extract more oil, the gas would instead be left underground and removed from the atmosphere. This promised breakthrough technology would allow climate friendly coal and so the continued use of this fossil fuel. But long before the world would witness any such schemes, the hypothetical process had been included in climate-economic models. In the end, the mere prospect of carbon capture and storage gave policy makers a way out of making the much needed cuts to greenhouse gas emissions.
The rise of net zero
When the international climate change community convened in Copenhagen in 2009 it was clear that carbon capture and storage was not going to be sufficient for two reasons.
First, it still did not exist. There were no carbon capture and storage facilities in operation on any coal fired power station and no prospect the technology was going to have any impact on rising emissions from increased coal use in the foreseeable future.
The biggest barrier to implementation was essentially cost. The motivation to burn vast amounts of coal is to generate relatively cheap electricity. Retrofitting carbon scrubbers on existing power stations, building the infrastructure to pipe captured carbon, and developing suitable geological storage sites required huge sums of money. Consequently the only application of carbon capture in actual operation then – and now – is to use the trapped gas in enhanced oil recovery schemes. Beyond a single demonstrator, there has never been any capture of carbon dioxide from a coal fired power station chimney with that captured carbon then being stored underground.
Just as important, by 2009 it was becoming increasingly clear that it would not be possible to make even the gradual reductions that policy makers demanded. That was the case even if carbon capture and storage was up and running. The amount of carbon dioxide that was being pumped into the air each year meant humanity was rapidly running out of time.
With hopes for a solution to the climate crisis fading again, another magic bullet was required. A technology was needed not only to slow down the increasing concentrations of carbon dioxide in the atmosphere, but actually reverse it. In response, the climate-economic modelling community – already able to include plant-based carbon sinks and geological carbon storage in their models – increasingly adopted the “solution” of combining the two.
So it was that Bioenergy Carbon Capture and Storage, or BECCS, rapidly emerged as the new saviour technology. By burning “replaceable” biomass such as wood, crops, and agricultural waste instead of coal in power stations, and then capturing the carbon dioxide from the power station chimney and storing it underground, BECCS could produce electricity at the same time as removing carbon dioxide from the atmosphere. That’s because as biomass such as trees grow, they suck in carbon dioxide from the atmosphere. By planting trees and other bioenergy crops and storing carbon dioxide released when they are burnt, more carbon could be removed from the atmosphere.
With this new solution in hand the international community regrouped from repeated failures to mount another attempt at reining in our dangerous interference with the climate. The scene was set for the crucial 2015 climate conference in Paris.
A Parisian false dawn
As its general secretary brought the 21st United Nations conference on climate change to an end, a great roar issued from the crowd. People leaped to their feet, strangers embraced, tears welled up in eyes bloodshot from lack of sleep.
The emotions on display on December 13, 2015 were not just for the cameras. After weeks of gruelling high-level negotiations in Paris a breakthrough had finally been achieved. Against all expectations, after decades of false starts and failures, the international community had finally agreed to do what it took to limit global warming to well below 2°C, preferably to 1.5°C, compared to pre-industrial levels.
The Paris Agreement was a stunning victory for those most at risk from climate change. Rich industrialised nations will be increasingly impacted as global temperatures rise. But it’s the low lying island states such as the Maldives and the Marshall Islands that are at imminent existential risk. As a later UN special report made clear, if the Paris Agreement was unable to limit global warming to 1.5°C, the number of lives lost to more intense storms, fires, heatwaves, famines and floods would significantly increase.
But dig a little deeper and you could find another emotion lurking within delegates on December 13. Doubt. We struggle to name any climate scientist who at that time thought the Paris Agreement was feasible. We have since been told by some scientists that the Paris Agreement was “of course important for climate justice but unworkable” and “a complete shock, no one thought limiting to 1.5°C was possible”. Rather than being able to limit warming to 1.5°C, a senior academic involved in the IPCC concluded we were heading beyond 3°C by the end of this century.
Instead of confront our doubts, we scientists decided to construct ever more elaborate fantasy worlds in which we would be safe. The price to pay for our cowardice: having to keep our mouths shut about the ever growing absurdity of the required planetary-scale carbon dioxide removal.
Taking centre stage was BECCS because at the time this was the only way climate-economic models could find scenarios that would be consistent with the Paris Agreement. Rather than stabilise, global emissions of carbon dioxide had increased some 60% since 1992.
Alas, BECCS, just like all the previous solutions, was too good to be true.
Across the scenarios produced by the Intergovernmental Panel on Climate Change (IPCC) with a 66% or better chance of limiting temperature increase to 1.5°C, BECCS would need to remove 12 billion tonnes of carbon dioxide each year. BECCS at this scale would require massive planting schemes for trees and bioenergy crops.
The Earth certainly needs more trees. Humanity has cut down some three trillion since we first started farming some 13,000 years ago. But rather than allow ecosystems to recover from human impacts and forests to regrow, BECCS generally refers to dedicated industrial-scale plantations regularly harvested for bioenergy rather than carbon stored away in forest trunks, roots and soils.
Currently, the two most efficient biofuels are sugarcane for bioethanol and palm oil for biodiesel – both grown in the tropics. Endless rows of such fast growing monoculture trees or other bioenergy crops harvested at frequent intervals devastate biodiversity.
It has been estimated that BECCS would demand between 0.4 and 1.2 billion hectares of land. That’s 25% to 80% of all the land currently under cultivation. How will that be achieved at the same time as feeding 8-10 billion people around the middle of the century or without destroying native vegetation and biodiversity?
Growing billions of trees would consume vast amounts of water – in some places where people are already thirsty. Increasing forest cover in higher latitudes can have an overall warming effect because replacing grassland or fields with forests means the land surface becomes darker. This darker land absorbs more energy from the Sun and so temperatures rise. Focusing on developing vast plantations in poorer tropical nations comes with real risks of people being driven off their lands.
And it is often forgotten that trees and the land in general already soak up and store away vast amounts of carbon through what is called the natural terrestrial carbon sink. Interfering with it could both disrupt the sink and lead to double accounting.
As these impacts are becoming better understood, the sense of optimism around BECCS has diminished.
Pipe dreams
Given the dawning realisation of how difficult Paris would be in the light of ever rising emissions and limited potential of BECCS, a new buzzword emerged in policy circles: the “overshoot scenario”. Temperatures would be allowed to go beyond 1.5°C in the near term, but then be brought down with a range of carbon dioxide removal by the end of the century. This means that net zero actually means carbon negative. Within a few decades, we will need to transform our civilisation from one that currently pumps out 40 billion tons of carbon dioxide into the atmosphere each year, to one that produces a net removal of tens of billions.
Mass tree planting, for bioenergy or as an attempt at offsetting, had been the latest attempt to stall cuts in fossil fuel use. But the ever-increasing need for carbon removal was calling for more. This is why the idea of direct air capture, now being touted by some as the most promising technology out there, has taken hold. It is generally more benign to ecosystems because it requires significantly less land to operate than BECCS, including the land needed to power them using wind or solar panels.
Unfortunately, it is widely believed that direct air capture, because of its exorbitant costs and energy demand, if it ever becomes feasible to be deployed at scale, will not be able to compete with BECCS with its voracious appetite for prime agricultural land.
It should now be getting clear where the journey is heading. As the mirage of each magical technical solution disappears, another equally unworkable alternative pops up to take its place. The next is already on the horizon – and it’s even more ghastly. Once we realise net zero will not happen in time or even at all, geoengineering – the deliberate and large scale intervention in the Earth’s climate system – will probably be invoked as the solution to limit temperature increases.
One of the most researched geoengineering ideas is solar radiation management – the injection of millions of tons of sulphuric acid into the stratosphere that will reflect some of the Sun’s energy away from the Earth. It is a wild idea, but some academics and politicians are deadly serious, despite significant risks. The US National Academies of Sciences, for example, has recommended allocating up to US$200 million over the next five years to explore how geoengineering could be deployed and regulated. Funding and research in this area is sure to significantly increase.
Difficult truths
In principle there is nothing wrong or dangerous about carbon dioxide removal proposals. In fact developing ways of reducing concentrations of carbon dioxide can feel tremendously exciting. You are using science and engineering to save humanity from disaster. What you are doing is important. There is also the realisation that carbon removal will be needed to mop up some of the emissions from sectors such as aviation and cement production. So there will be some small role for a number of different carbon dioxide removal approaches.
The problems come when it is assumed that these can be deployed at vast scale. This effectively serves as a blank cheque for the continued burning of fossil fuels and the acceleration of habitat destruction.
Carbon reduction technologies and geoengineering should be seen as a sort of ejector seat that could propel humanity away from rapid and catastrophic environmental change. Just like an ejector seat in a jet aircraft, it should only be used as the very last resort. However, policymakers and businesses appear to be entirely serious about deploying highly speculative technologies as a way to land our civilisation at a sustainable destination. In fact, these are no more than fairy tales.
The only way to keep humanity safe is the immediate and sustained radical cuts to greenhouse gas emissions in a socially just way.
Academics typically see themselves as servants to society. Indeed, many are employed as civil servants. Those working at the climate science and policy interface desperately wrestle with an increasingly difficult problem. Similarly, those that champion net zero as a way of breaking through barriers holding back effective action on the climate also work with the very best of intentions.
The tragedy is that their collective efforts were never able to mount an effective challenge to a climate policy process that would only allow a narrow range of scenarios to be explored.
Most academics feel distinctly uncomfortable stepping over the invisible line that separates their day job from wider social and political concerns. There are genuine fears that being seen as advocates for or against particular issues could threaten their perceived independence. Scientists are one of the most trusted professions. Trust is very hard to build and easy to destroy.
But there is another invisible line, the one that separates maintaining academic integrity and self-censorship. As scientists, we are taught to be sceptical, to subject hypotheses to rigorous tests and interrogation. But when it comes to perhaps the greatest challenge humanity faces, we often show a dangerous lack of critical analysis.
In private, scientists express significant scepticism about the Paris Agreement, BECCS, offsetting, geoengineering and net zero. Apart from some notable exceptions, in public we quietly go about our work, apply for funding, publish papers and teach. The path to disastrous climate change is paved with feasibility studies and impact assessments.
Rather than acknowledge the seriousness of our situation, we instead continue to participate in the fantasy of net zero. What will we do when reality bites? What will we say to our friends and loved ones about our failure to speak out now?
The time has come to voice our fears and be honest with wider society. Current net zero policies will not keep warming to within 1.5°C because they were never intended to. They were and still are driven by a need to protect business as usual, not the climate. If we want to keep people safe then large and sustained cuts to carbon emissions need to happen now. That is the very simple acid test that must be applied to all climate policies. The time for wishful thinking is over.
This article, written by Evan Lim, describes how glaciers are disappearing much faster that previous evidence based studies have estimated. Lim outlines the disastrous effects on communities.
Glaciers are disappearing to twice as fast as previous studies estimated, with disastrous effects on many communities.
Two new studies suggest that recent estimates of global ice melt are conservative.
In other words, ice is melting much more rapidly than experts thought. As a result, sea levels are rising faster as well.
The first study combines various observations from satellites, on-the-ground measurements, and model-based estimates to create a clearer picture of the state of Earth’s ice between 1994 and 2017. Essentially, it captures a global tally of change in ice mass over that time period. The resulting measurements of ice loss and sea level rise fall in the upper range of scenarios forecast by the Intergovernmental Panel on Climate Change (IPCC), a body within the United Nations meant to provide objective science related to climate change. The IPCC’s scenarios were laid out in their 2019 special report on oceans and the cryosphere, itself a recent overview of assessment work.
Faster sea level rise means that more areas will experience devastating floods sooner, and we are already seeing more of such events.
The second study zooms in on a particular region, rather than compiling measurements at the global scale. Focusing on Greenland, this study investigates how warmer ocean water affects marine terminating glaciers — those that end at the ocean. The authors identified at least 74 glaciers with retreats strongly influenced by warmer ocean waters, which expedite mass loss by undercutting a glacier’s base. Thus, the rest of the glacier is weakened and can collapse. Importantly, glacial melt contributes to rising sea levels; icebergs calving as glaciers thin adds water to the oceans.
Top and bottom illustrations show how the water thins the ice from below, making it easier for pieces to break off. (Source: Michael Wood et. al./Ocean forcing)
The authors of the first study emphasized that there is little doubt that the majority of ice loss is due to climate warming. In an interview with GlacierHub, Michael Zemp, director of the World Glacier Monitoring Service and a professor of glaciology and geomorphodynamics at the University of Zurich who is not affiliated with the study, stated that “Overall, the data show that climate change is happening and impacts are only increasing.”
Zemp also highlighted the complexity of systems in the cryosphere, emphasizing an important dynamic between the two studies in question. Broadly, the driving force of increased ice melt is climate warming. However, within glaciated regions around the world, there are specific characteristics that need to be taken into consideration.
For example, as the Greenland study demonstrates, the region’s glaciers are losing mass much more quickly as the ocean waters melt them from below, making it more easy for pieces to break and fall off. As this regional phenomenon affects the glaciers so significantly, the study authors point out that “projections that exclude ocean-induced undercutting may underestimate mass loss by at least a factor of 2.”
From the different characteristics of each region to the various measurement types (satellite, on-the-ground, modeling) to the time periods in which measurements are observed, models of the cryosphere have much to incorporate. Zemp notes that reports by the IPCC, which attempt to pull data from many different studies, can suffer as a result of the challenges of incorporating wide-ranging factors.
When asked how to reduce ice melt, Walter Immerzeel, a professor at Utrecht University, answered,
“the only real option is to reduce greenhouse gas emissions ASAP. The re-entry of the U.S. in the Paris climate agreement is a hopeful sign.”
Zemp’s conclusion echoed Immerzeel’s:
“the response is not easy, but still very simple. We have to reduce greenhouse gas emissions, and the Paris Agreement will hopefully help with this.”
The Greenland study notes that from 2008-2017, there was a cooling period in the ocean near Greenland. Despite this cooling, grounded ice (ice on land) continued to retreat significantly. As a result of previous warming, the glaciers have already been removed from their state of equilibrium, meaning the balance between mass gain and loss is gone. Even if emissions stopped immediately, there would still be lingering effects and mass loss as a result of the damage that has already been done. If emissions stopped, global temperatures would still be high enough for ice to continue to melt.
“It [climate change] was already urgent, but these conclusions further emphasize this. We need to act now and invest in both mitigation (reducing emissions) and adaptation (being prepared for the impact),” Immerzeel told GlacierHub.
He also noted that increased ice melt has significant implications for communities which rely on glaciers as sources of fresh drinking water and water for irrigation. For example, villages in Peru rely heavily on the Cordillera Blanca mountain range. The mountains and glaciers provide a rich cultural history, economic benefits through tourism and water used for irrigation, tourist guesthouses and household consumption. As the glaciers melt, the traditions of the culture that rely on the glaciers disappear, and people’s livelihoods are threatened by the impacts on tourism and agriculture and the sudden appearance of floods.
While certain damages are unavoidable, there can absolutely be more harm to come if significant action is not taken now.
Whether action is undertaken to protect current vulnerable communities or future generations, reducing emissions can shrink the burden people will inevitably have to bear. Communities are being affected as glaciers melt and sea levels rise, but the extent to which these damages will occur is still uncertain and can still be changed if the right measures are taken.
This article was written by Evan Lim, Columbia University Earth Institute, and published in Climate & Capitalism on February 17th, 2021. You can read at source here.
