Geoengineering: Assessing Risks in the Era of Planetary Security - Report

[Geoengineering News]

https://carnegieendowment.org/research/2025/07/geoengineering-assessing-risks-in-the-era-of-planetary-security?locale=en&token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjY2MjE5Mjk3ZjE5ZTlkODgzMjY2MzViMyIsImNvbGxlY3Rpb24iOiJ1c2VycyIsImVtYWlsIjoibWF0dGlhLmJhZ2hlcmluaUBjZWlwLm9yZyIsImlhdCI6MTcyNjgxODM3MCwiZXhwIjoxNzU4MzU0MzcwfQ.CRhM0Kp3Th9V3IV_eHR7v-rH6n_akyCav1L11atH2qQ&lang=en

As the effects of climate change intensify, interest in geoengineering approaches is ramping up. But these methods risk creating new ecological and security threats, undermining urgent systemic transitions.

Authors

Olivia Lazard,  Mandi Bissett, and James Dyke

Published on July 16, 2025

Summary

The 1.5° Celsius global warming threshold that climate scientists have warned against for decades has been breached for several consecutive months over the last two years. This page-turning moment marks humanity’s entry into climate overshoot. At the same time, a set of radical solutions known as geoengineering is increasingly presented as a potential emergency remedy to climate breakdown. Geoengineering technologies are intentional interventions in the Earth system that aim to lessen the impacts of climate change and even reverse increases in global temperatures. These technologies represent a significant shift in approach to both climate action and global security.

Planetary Interventions with Long-Term Implications

Geoengineering encompasses two primary approaches: carbon dioxide removal (CDR) and solar radiation management (SRM). CDR methods aim to extract carbon dioxide (CO2) from the atmosphere or the ocean, while SRM techniques seek to artificially cool the planet. Current CDR capacity is minimal, achieving approximately 2.2 billion metric tons of carbon dioxide (GtCO2) per year. This is primarily through afforestation, although significant resources are now being directed toward increasing ocean-based sequestration and engineered systems, such as direct air capture. SRM proposals include controversial strategies, such as stratospheric aerosol injection, which could provide rapid temperature reductions but with the potential to cause considerable damage to regional climates.

Geoengineering approaches are often discussed simply in relation to their potential to reduce CO2 emissions or shave off peak temperatures, without reference to the broader systems they take from and impact: human, ecological, international, and planetary security. As such, the inputs these approaches require and the varied categories of risk they produce are often unexplored or examined in silos.

In fact, what lies behind the potential deployment of geoengineering is a series of risks across several domains. The individual and collective impacts of these risks will change not only the logic of climate action but also, more broadly, the security paradigms in which the international community has operated for decades, if not centuries. For the first time in history, humankind is contemplating the deliberate deployment of Earth-system interventions at a planetary scale with implications that could span centuries. These interventions, intended to control the planet’s climate, will, at best, reduce—or, at worst, undermine—the natural building blocks that provide ecosystem services well beyond climate regulation.

Individual and Collective Risks

This paper is a primer for policymakers, particularly in Europe. It introduces a novel framework through which to view the risks associated with the individual and combined effects of various geoengineering approaches.

Any individual geoengineering method may carry one or more of three distinct risks:

It does not work: The method does little or nothing to stop climate change impacts or even increases emissions or temperatures.

It causes harm: The method damages and destabilizes already-fragile biophysical and social systems.

It exacerbates international tensions: The method erodes global peace, security, and cooperation, given the existing political context and the lack of any international governance framework for CDR or SRM.

Taken as a whole, meanwhile, geoengineering poses three forms of global catastrophic risk:

Termination shock: Global temperatures increase rapidly if SRM is deployed but then stopped suddenly without significant emissions reductions having taken place.

Systemic destabilization: Geoengineering compounds existing risks and vulnerabilities as cascading failures create the potential for large, possibly nonlinear, and hard-to-reverse ecosystem and societal changes.

Overshoot risks: Geoengineering leads to irreversible changes in Earth systems, as reliance on CDR and SRM delays rapid emissions reductions and undermines the effectiveness of mitigation.

The world has effectively entered the age of planetary security, albeit with no guiding analytical, governance, or legal compass to conceptualize and organize it. In this era, security considerations must increasingly guide the development of frameworks to govern the safety, boundaries, and integrity of both the biosphere and the technosphere. Such frameworks must also regulate the geostrategic competition that is taking place in both domains at the expense of human, ecological, and collective security.

Source: CARNEGIE EUROPE