International political boundaries are arbitrary creations. Today’s borders are better described as imaginary lines on maps, rather than hard barriers between states. Often using mountains, rivers, or other geographical landmarks, modern borders are entrenched in historic tradition rather than logic and fact. As a result, today’s international borders are poorly equipped to handle modern challenges, in particular climate change, which has already begun to threaten the most important state resource, fresh water.

As the national security ramifications of climate change grow more pronounced, climate manipulation technologies, known as geoengineering, will become more attractive as a method of staving off climate-related security emergencies.  However, geoengineering technologies could disrupt the global ecological status quo, and could pose a potentially coercive (and very serious) threat to peace. Is it possible to obtain the potential benefits of these game-changing technologies, while avoiding spurring violence and conflict?  In a recent article in Strategic Studies Quarterly, we argue that just war theory—which defines the concepts of “right” and “wrong” in warfare—could provide ethical standards for security decision-makers as they consider whether or how geoengineering should be used to address the climate challenge.

I remember the first moment when my interest in national security came crashing into ecological reality. I was on a U.S. government trip to Central Asia to inspect uranium mines in the newly-independent states of the former Soviet Union. The Cold War security imperative to achieve nuclear superiority had done a number on the environment there: Uranium was leached from the ground with sulfuric acid, transformed into a uranium oxide powder called yellowcake, and shipped off to be enriched for nuclear reactor fuel or weapons. The generals in Moscow who issued these orders did not see the collateral damage that their idea of security wreaked on the environment in Central Asia. In their attempt to out-weaponize the United States, they laid waste to the groundwater, agriculture, and public health of their own citizens.