Exploring Stratospheric Aerosol Injection as a Climate Solution
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Chapter 1: The Promise of Stratospheric Aerosol Injection
Harvard University is embarking on a significant endeavor to investigate whether reflecting sunlight back into space can help mitigate climate change. Frank Keutsch, an atmospheric scientist at Harvard, leads this initiative known as the Stratospheric Controlled Perturbation Experiment (SCoPEx). This experiment aims to gather crucial data regarding the risks associated with Stratospheric Aerosol Injection (SAI).
SAI is envisioned as a temporary remedy for global warming. The concept involves dispersing aerosol particles into the atmosphere to reflect a small fraction of sunlight away from Earth. Keutsch theorizes that this method could facilitate controlled global dimming, potentially cooling the planet by about 1.5 degrees Celsius—enough to stave off catastrophic climate effects, albeit for a limited time.
Evidence from natural phenomena, such as large volcanic eruptions, suggests that global dimming effects are typically short-lived, which raises questions about the permanence of atmospheric alterations resulting from SAI.
Moreover, SAI presents an economically appealing option, with a global intervention projected to cost around $20 billion annually—a sum that could be managed by the United States alone. If executed successfully, SAI could grant humanity the vital time needed to devise long-term strategies to combat climate change.
However, despite its potential, Harvard decided to delay Keutsch's project last year. Notably, Bill Gates has shown support for the $3 million initiative, which was initially scheduled to commence last summer.
Unfortunately for Gates, just weeks before the planned launch in April 2021, Harvard officials postponed SCoPEx, citing concerns over its possible effects on the host nation, Sweden. This hesitation was compounded by significant protests from Sweden’s indigenous Sami people, as well as organizations like Greenpeace and Friends of the Earth, alongside numerous prominent climate scientists.
Section 1.1: Activist Concerns over SAI Research
Many climate activists have raised alarms regarding even minor experiments with SAI. Environmental journalist Bill McKibben, writing for The New Yorker, cautions against the moral hazards associated with developing such technologies. He argues that these "technofixes" could serve as distractions for influential groups aiming to avoid necessary and aggressive climate action.
This concern is valid: if technology appears to offer a safety net for affluent polluters, such as the United States, it may diminish the urgency for comprehensive political, legal, and cultural changes essential for long-term climate resilience.
In addition to concerns about moral hazards, Climate Action Network International highlights the unpredictable "transboundary risks" tied to geoengineering. The potential impacts of SAI on local ecosystems, agricultural productivity, and global geopolitics remain uncertain, and the only way to assess these risks would be through large-scale implementations, which could cross the line from experimentation to deployment.
Furthermore, Oxford geophysicist Raymond Pierrehumbert warns of "termination shock," which refers to the rapid temperature rise that might occur if SAI were halted after being implemented. This implies that once aerosol injection begins, it may be impossible to stop without severe consequences.
Section 1.2: The Case for SCoPEx
Despite these valid concerns, it is crucial to recognize that SCoPEx primarily focuses on examining a specific method for SAI delivery rather than broader atmospheric manipulation effects. The experiment plans to limit aerosol injection to 2 kg (approximately 4.5 lbs) of particulates, which would minimally influence the atmosphere.
SCoPEx could offer valuable insights into the operational mechanisms of SAI on a global scale and help clarify uncertainties raised by critics. Additionally, a 2015 Yale University study discovered that informing individuals about SAI could lead to increased concern about climate risks, countering the moral hazard argument posited by McKibben and CAN.
In essence, keeping the public uninformed about SAI doesn't effectively motivate them to reduce carbon emissions; in fact, the opposite appears true.
While the potential for "termination shock" is a legitimate concern regarding extensive SAI deployment, SCoPEx’s limited scope mitigates the risks identified by Pierrehumbert.
Ultimately, Keutsch's experiment could validate some of the objections against SAI, which is precisely why it is essential to proceed. It will deepen our understanding of SAI's risks before it becomes a favored solution.
Knowledge is Power
SCoPEx serves as an opportunity to illuminate the possibilities for climate intervention. Given the widespread indifference towards the climate crisis among the largest polluters, SAI might represent a last resort. Thus, it is imperative that SCoPEx moves forward.
The second video titled "White House: Blocking the sun could stop climate change – but how can it be done?" explores the viability and implications of utilizing SAI as a climate intervention strategy, further highlighting the debate around this controversial topic.