Geoengineering and the Use of Force

(Published in Opinio Juris, Jan. 20, 2021).

It is now widely accepted that the climate change crisis is going to contribute to increasing levels of armed conflict among and within states in the coming decades. Less widely considered is the effect the crisis may have on the jus ad bellum regime. In a two-part essay in Opinio Juris (and in a much longer law review article), I have suggested that there will be growing pressure to relax the jus ad bellum regime when the more dire consequences of the climate change crisis begin to manifest themselves. That is, there will be mounting claims that the threat or use of force may be justified against those “climate rogue states” perceived to be recklessly and unlawfully contributing to the growing threat to international peace and security.

This argument may seem rather radical and unlikely from today’s perspective. But in this essay, I will examine how the case of geoengineering may help to illustrate just how some of the threats posed by climate change will create real tension for the jus ad bellum regime. The essay explores the hypothetical situation in which one country moves to unilaterally engage in a geoengineering scheme that many other states think will cause catastrophic harm to the climate and the ecosystem. How would the international community likely respond, and with what implications for international law?


As most readers will know, the term geoengineering refers to large-scale intervention and manipulation of the environmental systems for purposes of either reducing the pace or countering the effects of climate change. There are many different avenues being explored, ranging from different methods of carbon dioxide removal (CDR), to various forms of solar management regulation (SRM). The latter is a broad category of methods that aim to lower or maintain the temperature of the Earth’s atmosphere by reducing the exposure of the Earth’s surface to the full brunt of energy from the sun.

Read moreGeoengineering and the Use of Force