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The World Needs ‘Rapid Climate Cooling’ as 2℃ Overshoot Now Likely, New Research Warns

Scientists are warning that the climate situation is so dire that we will not only need to withdraw carbon from the atmosphere but begin exploring controversial solar geoengineering technologies to cool the planet, reports Nafeez Ahmed

Photo: Zoonar/David Freigner/Alamy

The World Needs ‘Rapid Climate Cooling’ as 2℃ Overshoot Now LikelyNew Research Warns

Scientists are warning that the climate situation is so dire that we will not only need to withdraw carbon from the atmosphere but begin exploring controversial solar geoengineering technologies to cool the planet, reports Nafeez Ahmed

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A recent paper in Nature Climate Change found that there is now a two-thirds chance of exceeding the 1.5℃ climate safety threshold after 2030 and breaching 2℃ by 2057. But this was not the first time that experts had pointed out how rapidly the world is hurtling toward dangerous global heating.

Last year, a paper published in the Climate Risk Management journal concluded that “dangerous climate target overshoot is almost inevitable” and the only way to now mitigate this is to stop carbon emissions as soon as possible, remove carbon dioxide from the atmosphere, and deploy technologies “for rapidly cooling global temperatures”.

“At this critical time, the international community must prioritise researching and developing a feasible overshoot risk management plan or risk irreversible catastrophic damage to the biophysical and physiochemical systems that support human civilisation,” Dr Graeme Taylor, of the University of Queensland’s Global Change Institute, the report’s co-author, said.

Sleepwalking Into Catastrophe

According to the UN Environment Programme’s 2021 Emissions Gap report, to limit global heating to 1.5C, the world must halve greenhouse gas emissions in just eight years.

“This will not happen,” Dr Taylor told Byline Times. “Despite new national pledges, emissions are forecast to keep rising, not falling. The 1.5°C target will be passed next decade, with potentially catastrophic consequences.”

Although many scientists insist that this is ‘technically’ possible, an increasing number of privately believe that, due to the reality of political inertia, we are bound to breach this limit. This could have catastrophic consequences.

Warming above 1.5°C would kill off most coral reefs and make much of the tropics unliveable. At 1.6°C, most of the Greenland ice sheet would melt, eventually raising sea levels by as much as seven metres. And some 20 to 30% of the world’s land surface would become significantly drier.

Yet the biggest risk, according to Dr Taylor, is that global heating at this level could “trigger uncontrollable feedbacks”.

“The first climate tipping point, the complete melting of summer Arctic Sea ice, could occur in a decade,” he told this newspaper.

As the research concludes that dangerous climate change is virtually inevitable, it argues that it is now urgently necessary to explore technologies that can rapidly cool global temperatures and remove carbon dioxide from the atmosphere.

“Global average temperatures are already measurably impacting the Earth’s systems at 1.2 °C above preindustrial levels,” it states. “Many human and environmental systems cannot adapt to higher temperatures, which may exceed critical tipping points in physical climate and ecological systems.”

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Nafeez Ahmed

Global Cooling

These risks are compounded by the probability of overshooting the international 2°C limit “due to political obstacles and systemic inertia from existing greenhouse gases, warming oceans, and the decades required to replace existing infrastructure”.

While most UN mitigation scenarios involve various forms of large-scale carbon dioxide removal to return temperatures to safe levels, one of the biggest problems is that this “will act too slowly to prevent dangerous overshoot”.

There is therefore an urgent need to investigate “whether rapid climate cooling measures may be required to reduce the risks associated with high temperatures” in the period in which global heating is likely to breach the danger zone while we are still decarbonising the global economy.

One of the most promising approaches to such climate cooling – Dr Taylor and the report’s co-author Sue Vink, a Principal Research Fellow at the University of Queensland conclude – is solar radiation management.

This can involve many different technologies designed to reflect solar energy back into space. Some are as simple as painting roofs white to reduce urban heat or creating marine clouds to reduce the likelihood of corals bleaching. Other more controversial technologies involve releasing reflective aerosols into the atmosphere or placing giant mirrors in orbit around the Earth.

Dr Taylor said that “these technologies cannot be used until their risks are understood and mitigated”. But he also argued that they will be required “to constrain temperature overshoot until greenhouse gas concentrations are stabilised at safe levels” – so we need to understand their potential risks and benefits.

“Dangerous climate target overshoot is almost inevitable,” Dr Taylor told Byline Times. “The planet is already suffering dangerous climate change and we urgently need to reduce average global temperatures to prevent the loss of the Arctic, coral reefs, rainforests and other critical ecosystems and avoid crossing climate tipping points and triggering runaway climate change.”

Critics of solar geoengineering have argued that even discussing the technology increases the risk of unilateral actions and could fuel delays to decarbonisation. Currently, geoengineering technologies are already being explored by various governments without global public accountability.

Earlier this year, a team of scientists writing in the Wiley Interdisciplinary Review Climate Change argued that “solar geoengineering at planetary scale is not governable in a globally inclusive and just manner within the current international political system”. They argued that the risks and benefits are “poorly understood” and might not ever be properly understood before deployment – with too much uncertainty about the impacts on regional weather patterns, agriculture and availability of food and water.

Their biggest concern is that fair, collective and responsible use of such technologies requires the most powerful countries to grant multilateral institutions overarching veto power and control over their deployment, to ensure the interests and rights of the most vulnerable countries. But, as such international structures and organisations “with convincing means of democratic control and unprecedented enforcement powers” don’t even exist, then the fair and responsible use of solar geoengineering is impossible.

They have therefore called on governments and the UN to immediately take political control of these technologies and to agree an “International Non-Use Agreement on Solar Geoengineering” to ensure they are not deployed.


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A Precautionary Approach?

Perhaps the most basic problem with this line of argument is that it fails to credibly address the key issue – the high and currently increasing probability that we will breach the climate danger zone.

The other problem is the solution: after dismissing the prospect that existing multilateral institutions could provide a mechanism to regulate solar geoengineering, the study goes on to advocate that multilateral institutions and governments get together to regulate these technologies by collectively agreeing and enforcing their non-use – which is, in effect, exactly what they just said is going to be impossible.

According to Dr Graeme Taylor, critics of these technologies raise important and legitimate questions about their potential risks, but overlook that the best scientific evidence suggests we are now already too far gone. The onus then is not to simply ban all geoengineering approaches wholesale, but to identify the safest approaches.

Dr Taylor also emphasised that geoengineering should not be used to legitimise business-as-usual. Instead, the Paris Agreement needs to be supplemented with what he and Vink call “a realistic overshoot risk management plan”, combining three approaches.

First and foremost, they argue, we must rapidly reduce greenhouse gas emissions as fast as possible. Secondly, as dangerous climate change is already here, we will need deploy large scale carbon dioxide removal measures to draw down atmospheric carbon. And thirdly, they believe that we will need to use solar radiation management technologies to keep temperatures within safe limits until CO2 levels have been reduced to a level that stabilises the climate.

“I believe governments will inevitably use solar geoengineering to prevent increasingly extreme weather causing catastrophic crop failures,” said Dr Taylor. Many governments may even start taking unilateral action and have already started doing so – meaning that we need global regulation right now and cannot have that without better research.

The paper thus calls for a robust global research programme led by the UN “on the risks, costs and benefits of all potential mitigation methods versus the likely risks and costs of overshooting safe temperatures” – alongside an international agreement that doesn’t ban geoengineering, but governs its use to avoid the possibility that governments might take dangerous unilateral action.  

Dr Taylor referred to the ‘precautionary principle’ as the basis for recognising the urgent need to scientifically evaluate both carbon removal and solar radiation management technologies.

“While it could be very dangerous to deploy untested technologies, the consequences could be catastrophic if climate interventions were not used in time to prevent dangerous overshoot,” he said. “Opponents need to recognise that the alternative to researching and deploying geoengineering is to leave all efforts to limit temperature increases to reducing emissions, a strategy that would be almost certain to fail.”

He argues that the UN’s Intergovernmental Panel on Climate Change should coordinate the urgently needed research so that we can understand the risks and effectiveness of these technologies more clearly.

Transforming the System

As Byline Times has previously reported, other research shows that existing technologies in the energy, transport and food sectors are on track to disrupt carbon-intensive industries, responsible for 90% of emissions, within the next two decades. While these disruptions cannot be stopped, they can be delayed.

But, if dangerous climate change is already here, the risk is that delaying these disruptions by clinging onto the incumbent industries as long as possible places Earth in the climate danger zone for far too long – potentially triggering dangerous feedback effects that could, in turn, trigger worst-case scenarios.

As a consequence, for Dr Taylor, carbon removal and solar radiation management may be the only ways to ensure a stable climate.

“While I agree that new technologies will cause massive, rapid shifts in energy, food and transportation”, he said, “the process will be uneven and delayed due to the combination of economic and political opposition and lags caused by the difficulties and costs of changing behaviours and transforming existing infrastructure. Although we can expect exponentially accelerating change, I expect it will still take decades to achieve net zero. During this time, total atmospheric concentrations of greenhouse gases will continue to rise, as will oceanic thermal inertia”.

The combined effect of the deployment of these disruptive technologies – solar, wind and batteries; electric vehicles (EV), eventually autonomous EVs, and Transport-as-a-Service; and precision fermentation and cellular agriculture (PFCA) – will be to dramatically reduce the costs of deploying potential CDR and SRM technologies.

Clean and abundant electricity combined with machine labour and new advances in materials would make these and many other such exotic technologies that are too expensive today, commercially viable and technologically feasible for the first time.

In other words, those CRD and SRM technologies will only become truly feasible once we’ve actually transformed and decarbonised our energy, transport and food systems. While that transformation involves more than just technology – governance, economic structures, values, mindsets, and beyond – we can accelerate the path to systems change by leveraging existing technologies in these three key sectors.

A growing number of scientists are warning that it may already be too late to avoid dangerous climate change. But it’s not too late to get out of the danger zone and speed ahead to a safe climate. Yet if we are going to succeed in doing so, we’ll need much more robust conversations to help inform the stark and difficult choices ahead.

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