Betting On Speculative Geoengineering May Risk An Escalating Climate Debt Crisis

Betting On Speculative Geoengineering May Risk An Escalating Climate Debt Crisis Vladi333 / shutterstock

The opening of the Oscar-winning film The Big Short, a comedy-drama on the global financial crisis of 2007-2008, begins with a famous quote: “It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.”

This phrase captures one of the main reasons why the US housing bubble popped in 2008, triggering the worst economic recession since the 1930s. The movie portrays an eccentric hedge fund manager discussing the idea of betting against subprime mortgage bonds. The investment bankers, at first, reply politely: “Those bonds only fail if millions of Americans don’t pay mortgages. That’s never happened in history.”

But it happened. And as a consequence, many people worldwide have suffered severely, and the enduring effects still haunt us, politically and economically, even a decade later.

In a new paper published in Climate Policy, we argue that a similar tragic “debt crisis” could unfold for climate change. The “debt” would be measured in excess carbon emissions, which will keep accumulating until we reach net-zero. In this scenario, the bankers are those who assume that the debt will be paid back by removing carbon from the atmosphere.

But such a bet will be necessary if we recklessly embark on the strategy of reducing emissions slowly and removing carbon later, while in the meantime using speculative technology to block out heat from the sun. Among climate scientists and policy analysts, this is the so-called temperature “overshoot and peak-shaving” scenario.

‘Overshoot and peak-shaving’

In December 2015, the world adopted the Paris Agreement and pledged to limit global temperature rise well below 2℃ – if not 1.5℃ – above pre-industrial levels. Despite that, global CO₂ emissions continue to rise.

The slow and uneven pace of global emissions reductions is increasing the likelihood of “overshoot” scenarios, in which warming will temporarily exceed 1.5 or 2°C, but will later fall to the target temperature through the large-scale deployment of negative emissions technologies. These remove CO₂ from the atmosphere by, for example, planting trees or scrubbing it through chemical filters and burying it deep underground.

But the world would still need to adapt to the impacts of increased warming during the overshooting period. Because of this concern, the idea of so-called “peak-shaving” has also emerged among some scientists who want to avoid such an overshoot by temporarily using solar geoengineering.

Solar geoengineering means dimming sunlight itself. In theory, the Earth could be cooled very quickly by, for example, spraying sulphate aerosols in the upper atmosphere.

Betting On Speculative Geoengineering May Risk An Escalating Climate Debt Crisis Small particles in the upper atmosphere could reflect a few percent of incoming solar radiation. Hughhunt, CC BY-SA

The concept of an “overshoot and peak-shaving” scenario is therefore based on the temporary use of solar geoengineering, combined with large-scale deployment of negative emissions technologies.

In this scenario, the two technologies are in a mutually dependent relationship – solar geoengineering is used to keep the temperature down for the time being, while negative emissions technologies are used to reduce atmospheric CO₂ to the point where solar geoengineering is no longer needed.

Emissions debt and temperature debt

But this assumed reciprocity may not work as intended. Here, the notion of debt is useful. As the sociologist Lisa Adkins suggests, the logic of debt rests on a promise to pay (back) in the future. In this sense, both overshooting and peak-shaving can be seen as acts of “borrowing” or “creating debt”.

Overshooting avoids reducing carbon emissions today by effectively borrowing emissions from the future (creating “emissions debt”), with a promise to pay back that debt later through negative emissions technologies.

Peak-shaving is borrowing global temperature (creating “temperature debt”) through the temporary use of solar geoengineering to cancel excess warming until the point when no further borrowing, of either sort, is needed.

In such an outcome the world will take on a double debt: “emissions debt” and “temperature debt”.

Betting On Speculative Geoengineering May Risk An Escalating Climate Debt Crisis Emissions debt results from the near-term excess of CO₂ emissions in the overshoot compared to the non-overshoot scenario, while temperature debt results from the temporary masking of warming committed by excess emissions above the target temperature. Asayama & Hulme

The analogy with housing loans

The fact of being indebted may not sound so bad. (Almost everyone has a debt of some kind in their everyday life, right?) But the key question is: can we duly pay off this “climate debt”? How credible is the promise?

Here, the analogy with housing loans is most useful for properly rating the riskiness of such debt repayment.

Given that overshoot allows slow rates of emissions reductions by “promising” that delays can be compensated later through carbon removal, this looks a bit like borrowing an adjustable-rate subprime mortgage loan. Peak-shaving, on the other hand, is more like borrowing additional loans for “home improvement”, which maintains house values – (keeps global temperature constant during the overshooting period).

Since most negative emissions technologies are still speculative or under development, overshoot should be rated like a subprime loan with a high risk of default. Just as American homeowners weren’t able to keep paying their mortgages after all, so negative emissions technologies may never be an effective enough way to take carbon out of the atmosphere.

This doesn’t sound like a secure, feasible investment. The failure to keep the overshoot promise of later repayment would lead to endless peak-shaving. Solar geoengineering would become an ongoing necessity – an unpayable massive “climate debt” accumulating year-by-year.

Framing matters — let’s not blind ourselves

Concerns over crossing so-called “tipping points” – paving the way toward a “hothouse Earth” – may push some people towards accepting overshooting and peak-shaving. But because this is a speculative scenario, it matters how we frame it.

Some scientists say that solar geoengineering is like a drug to lower high-blood pressure – an overdose is harmful, but a “well-chosen” and limited dose can lower your risks, helping you have a healthier life.

They suggest that solar geoengineering is not a substitute for cutting emissions but a supplement for containing global temperature increases. But this works only if negative emissions technologies are rolled out very swiftly on a massive scale.

The housing loans analogy sheds light on an important assumption that is implicitly built into such a scenario, namely that overshooting is simply like borrowing money (for example, a mortgage) and that people pay back mortgages. This was also the unquestioned assumption in the run up to the US housing market crisis and it created the systemic failure to notice the growing risk of the bubble bursting.

We shouldn’t fool ourselves into believing that a similar “debt crisis” will not happen for managing the risk of climate change. Beware the dubious promises of “overshoot and peak-shaving” technologies – they may well turn out to be risky subprime loans.

About The Author

Shinichiro Asayama, Visiting Scholar at Department of Geography, University of Cambridge and Mike Hulme, Professor of Human Geography, University of Cambridge

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Related Books

Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming

by Paul Hawken and Tom Steyer
9780143130444In the face of widespread fear and apathy, an international coalition of researchers, professionals, and scientists have come together to offer a set of realistic and bold solutions to climate change. One hundred techniques and practices are described here—some are well known; some you may have never heard of. They range from clean energy to educating girls in lower-income countries to land use practices that pull carbon out of the air. The solutions exist, are economically viable, and communities throughout the world are currently enacting them with skill and determination. Available On Amazon

Designing Climate Solutions: A Policy Guide for Low-Carbon Energy

by Hal Harvey, Robbie Orvis, Jeffrey Rissman
1610919564With the effects of climate change already upon us, the need to cut global greenhouse gas emissions is nothing less than urgent. It’s a daunting challenge, but the technologies and strategies to meet it exist today. A small set of energy policies, designed and implemented well, can put us on the path to a low carbon future. Energy systems are large and complex, so energy policy must be focused and cost-effective. One-size-fits-all approaches simply won’t get the job done. Policymakers need a clear, comprehensive resource that outlines the energy policies that will have the biggest impact on our climate future, and describes how to design these policies well. Available On Amazon

This Changes Everything: Capitalism vs. The Climate

by Naomi Klein
1451697392In This Changes Everything Naomi Klein argues that climate change isn’t just another issue to be neatly filed between taxes and health care. It’s an alarm that calls us to fix an economic system that is already failing us in many ways. Klein meticulously builds the case for how massively reducing our greenhouse emissions is our best chance to simultaneously reduce gaping inequalities, re-imagine our broken democracies, and rebuild our gutted local economies. She exposes the ideological desperation of the climate-change deniers, the messianic delusions of the would-be geoengineers, and the tragic defeatism of too many mainstream green initiatives. And she demonstrates precisely why the market has not—and cannot—fix the climate crisis but will instead make things worse, with ever more extreme and ecologically damaging extraction methods, accompanied by rampant disaster capitalism. Available On Amazon

From The Publisher:
Purchases on Amazon go to defray the cost of bringing you,, and at no cost and without advertisers that track your browsing habits. Even if you click on a link but don't buy these selected products, anything else you buy in that same visit on Amazon pays us a small commission. There is no additional cost to you, so please contribute to the effort. You can also use this link to use to Amazon at any time so you can help support our efforts.



follow InnerSelf on


 Get The Latest By Email



Fossil Fuel Production Plans Could Push Earth off a Climate Cliff
by The Real News Network
The United Nations is beginning its climate summit in Madrid.
Big Rail Spends More on Denying Climate Change than Big Oil
by The Real News Network
A new study concludes that rail is the industry that's injected the most money into climate change denial propaganda…
Did Scientists Get Climate Change Wrong?
by Sabine Hossenfelder
Interview with Prof Tim Palmer from the University of Oxford.
The New Normal: Climate Change Poses Challenges For Minnesota Farmers
by KMSP-TV Minneapolis-St. Paul
Spring brought a deluge of rain in southern Minnesota and it never seemed to stop.
Report: Today's Kids' Health Will Be Imperiled by Climate Change
by VOA News
An international report from researchers at 35 institutions says climate change will threaten the health and quality of…
How Supercharged Trash Gas Could Produce More Green Energy
by InnerSelf Staff
Synthetic compounds called “siloxanes” from everyday products like shampoo and motor oil are finding their way into…
300 Million Face Severe Risk of Climate-Fueled Coastal Flooding by 2050
by Democracy Now!
As a shocking new report finds that many coastal cities will be flooded by rising sea levels by 2050, Chile’s President…
Climate Warning: California Continues To Burn, Data Estimates Of Global Flooding
Ben Strauss, CEO and Chief Scientist of Climate Central joins MTP Daily to discuss alarming new information about…


Racing Ice Loss Strips Greenland Of Mass
Racing Ice Loss Strips Greenland Of Mass
by Tim Radford
Greenland is shrinking, losing ice seven times faster than a generation ago. Scientists have taken a new and ominous…
Lessons From The Hockey Rink Could Help Ontario Tackle Climate Change
Lessons From The Hockey Rink Could Help Ontario Tackle Climate Change
by Jennifer Lynes and Dan Murray
The Auditor General of Ontario’s recent report found the province’s current climate change plan is not based on “sound…
Climate Change Threatens A Scary Number Of Plant Species
Climate Change Threatens A Scary Number Of Plant Species
by InnerSelf Staff
Almost 40% of global land plant species are very rare, and these species are most at risk for extinction as the climate…
How Drought Is Affecting Water Supply In Australia’s Capital Cities
How Drought Is Affecting Water Supply In Australia’s Capital Cities
by Ian Wright and Jason Reynolds
The level of water stored by Australia’s capital cities has steadily fallen over the last six years. They are now…
How Jet Stream Changes May Hit Global Breadbaskets
How Jet Stream Changes May Hit Global Breadbaskets
by Alex Kirby
Food shortages and civil disturbances may result from changes in the jet stream winds which circle the Earth,…
How To Design A Forest Fit To Heal The Planet
How To Design A Forest Fit To Heal The Planet
by Heather Plumpton
Reforestation has enormous potential as a cheap and natural way of sucking heat-absorbing carbon dioxide out of the…
Investors Fight Back Against Climate Wreckers
Investors Fight Back Against Climate Wreckers
by Paul Brown
Investors are using their shareholdings to force polluting companies to change their ways and cut carbon emissions.
Americans Are Worried About Climate Change, But Underestimate How Serious It Is
Americans Are Worried About Climate Change, But Underestimate How Serious It Is
by Bobby Duffy
The world is often better and getting better than people think. Murder rates, deaths from terrorism and extreme poverty…