The contentious and ambiguous entanglement that military forces have with their natural environment inevitably sparkles public interest and academic research. So how does the existing scholarly work inform our assessment of this convergence?

When I recently reviewed this literature on ecologically relevant military activities, a number of differing impressions emerged. Some studies see armed forces adding to environmental problems. These effects are demonstrated both by a considerable global military carbon footprint and wartime environmental destruction emerging, for instance, from the Russian invasion of Ukraine.

Yet negative environmental externalities are also emerging from comparatively innocent political struggles, such as those arising between defense administrations and other stakeholders over land envisioned either for training grounds or wind farms. Militaries also are called upon to secure the vast and melting Arctic territories due to their economic and strategic importance. It is not without irony that military responses to an Arctic so severely impacted by climate change entail deploying the heavy, combustion-driven machinery that adds to these impacts.

The study of these entanglements might relate an easy and straightforward story if military actors created exclusively negative impacts on the environment. Yet military forces also field their conventional capabilities in response to environmental change. This, too, is a story of mixed intentions and successes.

Take Canada’s deployment of its armed forces in that nation’s largest-ever disaster response contingent during the wildfires of 2023. Or observe how the Chinese military was ordered to plant a new forest about as large as Ireland. In a wider sense, a growing number of military forces throughout the world now pursue emission reduction targets and other activities aimed at environmental protection. But not all of them are successful. For example, the Brazilian military’s efforts to combat illegal rainforest logging proved futile.

Indeed, the close examination undertaken by researchers reveals this to be a much more complex question than is commonly understood. And it is worth digging deeper.

Assessing Four Clusters of Ecologically-Relevant Military Activities

The tempo of research on the touchpoints between armed forces and climate change is increasing quickly. My own review suggests that this research has identified four roles that military forces play vis-à-vis the environment.

First, many studies do identify military complicity in global environmental change—and a long-term role in doing so.  To a large extent, the complicity derives from military forces’ often considerable greenhouse gas emissions but also from many other sources such as peacetime housing and, in particular, wartime destruction. An archetypical example is the use of defoliating herbicides such as Agent Orange in Vietnam but my review identifies several other, more recent cases.

A second role has emerged as a consequence of global environmental change, and it concerns the Anthropocene geopolitics involved in military forces’ responses to it. The militarization of the Arctic is perhaps the most prominent example. Yet other instances can be found in the military responses between India and China created by interstate tensions in the freshwater-rich Himalayas, and in increasingly militarized coast guard responses to fishery disputes.

The growing calls for military forces to engage in impact alleviation offers a third window into the question. As a consequence, military forces now are venturing into a multitude of new practices that involve many decarbonization and climate security strategies. These measures range from improved waste treatment guidelines to the ambivalent introduction of biofuels.

A final fourth role lies in the obstruction of climate-related policies. This is motivated by historical path-dependencies that tie military forces to the combustion of fossil energy. Different military forces employ varied means to affect and constrain the environment-related regulations imposed upon them, ranging from knowledge production over conventional lobbying to straightforward power politics.

A Topic for Environmental Peace and Conflict Research?

Empirical and theoretical puzzles remain as ecologically relevant military activities grow and diversify. Scholars who work at the nexus between environment and security are paying attention – and these questions should now take a central place in environmental peace and conflict research.

As we have seen, different armed forces engage in diverse ecologically relevant roles to varying degrees. Small nations with military forces that lack an air force or navy are less complicit than  those countries that regularly field large contingents for exercises or actual operations.

Further, engagements in Anthropocene geopolitics surely vary not only depending on a nation’s geographical location but also on its geopolitical culture. It also seems likely that both the uptake of impact alleviation activities and the employment of different tools of obstruction depend on whether a force is subjected to the strict constitutional controls of climate-ambitious democracies—or remains itself a major stakeholder of domestic politics.

Lastly, innovative case studies have paved the way for more comparative, explanatory research into militaries’ climate security policies. But another step has yet to be made. More research is urgently needed to match the considerable amount of military emissions, the growing share of a defense in national budgets and the increasingly contested international order.

Beyond the empirical puzzles they pose, the activities of militaries in the ecology space should be integrated more meaningfully into various streams of environmental peace and security research. As I argued in a previous piece, the six major branches of environmental peace and conflict research all possess their own puzzles and questions related to militaries’ eco-entanglements. Now is the time to answer them in a more systematic fashion.