In March of 2016, France’s Minister of Internal Affairs, Bernard Cazeneuve, announced that exercises simulating terrorist attacks would be organized in the ten French cities that were to host matches for the European Cup football championships in June and July. In Nîmes, 1,200 students from the National Police School gathered in the stadium with 480 experts from four ministries (Internal Affairs, Defense, Health, and Sports) to simulate a panicked crowd and coordinate the provision of services. In Marseille, a similar exercise that simulated evacuation from the stadium to hospitals was based on the scenario of an attack causing 185 casualties. Cazeneuve concluded his announcement by arguing that “French citizens must become sensitive to terrorist risks. They must be prepared to be surprised.” When a man driving a truck killed more than eighty people in Nice during July’s National Day celebration, a mode of attack that was indeed unexpected, the minister was criticized for not being prepared enough.

Four months prior to Cazeneuve’s exercises, the French authorities were getting prepared for a very different event: the 2015 climate change conference known as COP21, which gathered more than 150 heads of state in Paris to discuss measures to reduce the global emission of carbon dioxide. In his own simulation of these negotiations, Bruno Latour organized a series of diplomatic negotiations between representatives of the beings composing the globe. The goal of the simulation was to instantiate a state of war between the different representatives so that they could claim the territory to which they were attached. The rule was the following: “Name your enemies and define the territories that you are prepared to defend” (Latour 2015, 337). For instance, delegates of the oceans or the forest argued with delegates of the United States and Australia about the consequences of their energy politics. The scenario was not entirely written in advance, but instead created a stage for a political discussion to unfold, without using the term nature to provide easy compromises.

The possibilities opened by this discussion seemed to be closed by the attacks that happened just before the beginning of COP21, killing 130 people in the heart of Paris. While Latour’s simulation of the climate change summit raised the question of just who the enemy was, the attacks gave it a name and a territory: ISIS. And yet the simulations of terrorist attacks for the European Cup seemed to bring back some openness: they aimed at “being prepared to be surprised.”

Simulations of disasters emerged as techniques of risk management after World War II in the context of civil defense. They transformed the rationality of risk by focusing on events whose probability was unknown but whose consequences were catastrophic. They started with exercises that would immerse actors in scenarios of nuclear attack, such as the famous duck-and-cover exercises (see Davis 2007). Eventually, they were extended to all kinds of natural hazards, such as climate change intentionally caused by the Soviet Union (Hamblin 2013) or a pandemic initiated by a bioterrorist attack (Lakoff 2007).

Whether such simulations rehearse an intentional or unintentional catastrophe, their aim is preparedness: a state of vigilance cultivated through the imagination of disaster. And yet there is a difference between simulating a terrorist attack and simulating climate change. Why is it more difficult to imagine that we are at war in discussions about climate change than in the fight against terrorism? How can techniques of preparedness be extended from the military field to environmental issues? Is it only an extension of chains of causality, from the explosion of a bomb to the melting of ice, or do we have to change the way we imagine the future? The striking co-occurrence of the climate change summit and the terrorist attacks in Paris raised a difficult question: what kinds of enemies do we want to define for the Anthropocene? And how does this definition create a space for action?

Another technique of preparedness is the use of sentinel devices to send early-warning signals. The sentinel, like the disaster simulation, also has its origins in the military domain: a sentinel is a soldier going to the frontline to perceive in advance the movements of the enemy. Sentinels transform these movements into signals, thus creating a space of communication that fosters preparedness. In the context of climate change, sentinels raise the question of who the enemy is, but they do not answer it with reference to military sovereignty. Instead, they transform borders (between territories and between species) into problematic spaces.

While shadowy agencies patrol in anticipation of the next terrorist attack, sentinels record the signs of climate change: ice melting, species extinction, and extreme weather events (see Whitington 2013). The intermediary figure of the sentinel allows us to connect these radically different practices. The migratory bird or farm chicken infected with influenza, for example, could be announcing a potential pandemic. Implementing preparedness at the avian level (see Shortridge, Peiris and Guan 2003), experts of influenza have connected fears of sudden epidemic with awareness of environmental changes, such as the dramatic increase in the number of industrial chickens. Neither friends nor enemies, sentinel birds signal new vulnerabilities in relations between species.

It is right to say that we need enemies to initiate action in the time of the Anthropocene, but these enemies need not declare their intentions. A space of imagination is created by techniques of preparedness in which our vulnerabilities are reflected and acted upon. While the number of potential enemies imagined by simulation exercises could discourage action, their localization in sentinel species or territories produces new forms of inhabiting the world.