Although the Trump administration has embraced an official policy of denial, the reality of climate change—manifested in fires, floods, droughts, and hurricanes—is becoming hard to avoid. The administration’s stance has placed U.S. officials charged with preparing for future military contingencies in an absurd position. Thousands of military installations on U.S. soil are vulnerable to extreme weather events. Rising water levels and temperatures may have dire effects on key allies and aggravate conflicts within and between states. Klare has cleverly used the Pentagon’s continuing assessments of the impact of climate change and the military’s experience of dealing with its effects to illuminate not only the folly of denialism but also the seriousness of the potential climate threats. He traces a “ladder of escalation,” climbing from humanitarian disasters, to oil shocks, to disrupted supply chains, to collapsing states, to major-power conflicts (perhaps over water disputes). The book’s title is derived from a scenario in which the U.S. military must confront multiple warming-related crises abroad after fires and rising sea levels have immobilized it.