All Hell Breaking Loose examines climate change from the perspective of the U.S. military and the Pentagon. Michael T. Klare argues that the military's concern about global warming is less about debating the causes of climate change and more about preparing for its security consequences. The book investigates how climate-related disruptions could create conditions that require military, humanitarian and governmental responses.

Klare explores the connection between environmental stress and political instability, conflict and humanitarian crises. He examines how drought, food shortages, resource scarcity and displacement can put additional pressure on already fragile states, potentially contributing to civil disorder and conflict. The book also considers the possibility of large-scale migration as communities become increasingly vulnerable to environmental disruption.

A major part of the book focuses on the security implications of climate-related disasters. Hurricanes, floods, extreme weather and other disasters can require extensive emergency responses, including military assistance. Klare therefore looks at the armed forces not only as combat organizations but also as potential first responders during large-scale humanitarian emergencies.

The book also turns toward the Arctic, where melting ice is opening new sea routes and changing the strategic environment. Klare discusses how environmental transformation can create new geopolitical challenges involving access, transportation, resources and military planning.

Another important dimension is the vulnerability of the United States itself. Rising sea levels and increasingly severe climate-related disasters threaten American communities, infrastructure and military installations. Klare examines how these risks could affect the Pentagon's ability to maintain and operate its facilities.

The book ultimately presents climate change as a national-security and strategic-planning issue, arguing that governments and military institutions need to prepare for the instability and emergencies that climate disruption could produce.