In 2007, an influential analysis by 11 retired generals and admirals characterized climate change as a “threat multiplier” that could aggravate the conditions for conflict. Last week, in a follow-up report launched at the Wilson Center, members of the CNA Corporation’s Military Advisory Board framed climate change as a more direct and immediate risk, calling it a “catalyst for conflict.”

The new report re-examines the risks of climate change in the context of advancing science and a “more complex and integrated world.” Perhaps surprisingly, the group of retired flag officers from all four branches of the U.S. military also come out strongly in favor of cross-sectoral responses to climate change, noting that the food-water-energy nexus and demographic shifts are inextricably linked to vulnerability.

Rapid Population Growth Exacerbates Vulnerabilities

Since the Military Advisory Board’s 2007 report, world population has grown by more than a half a billion people. This growth means increased competition for natural resources, the authors write – specifically water, food, and energy, the availability of which is also exacerbated by climate change.

Among the report’s key findings:

As the world’s population and living standards con­tinue to grow, the projected climate impacts on the nexus of water, food, and energy security become more profound. Fresh water, food, and energy are inextricably linked, and the choices made over how these finite resources will be produced, distributed, and used will have increasing security implications.

The authors point to a recent U.S. National Intelligence Council assessment, which found that by 2030, population growth and a burgeoning global middle class will result in a 35 percent increase in demand for food, 40 percent increase in demand for freshwater, and 50 percent increase in demand for energy. Even without the effects of climate change, growing food demand will require greater energy and water inputs for agriculture; scarcer water supplies could mean greater energy use for desalination; and greater energy demands could put more arable land under production for biofuels, ramping up pressure for increased productivity on shrinking croplands.

Temperature increases in the middle latitudes will further increase demand for water and energy, the report finds, compounding stress and competition among sectors for limited resources. “The projected impacts of climate change are most profound in areas where the water-food-energy nexus is already stressed,” the authors note.

Urban areas and coastlines – areas at increased risk to climate change effects – have witnessed the most rapid population growth in recent decades. Expanding human settlement in coastal zones means more and more people face vulnerability to extreme weather events, storm surge, and flooding – and the military faces more and more response missions. When city services and infrastructure lag behind, urban growth can also increase people’s physical vulnerability to the impacts of climate change. “Burgeoning cities put enormous pressure on urban infrastructure – pressure that is only exacerbated by the effects of climate change, such as flooding,” the authors write.

The report also highlights the ways in which urban population growth can contribute to socio-political vulnerabilities, noting that rapid growth in cities can stress already-limited resources and hamper the ability of governments to provide necessary human support services, leaving residents more vulnerable to disenfranchisement and even extremist or revolutionary influences.

Guarding Against a “Failure of Imagination”

The Military Advisory Board is concise and direct in stating the growing security threats it sees posed by climate change, and the role that population growth plays in that mix:  “In short, the volatile mixture of population growth, insta­bility due to the growing influence of nonstate actors, and the inevitable competition over scarce resources will be multiplied and exaggerated by climate change.”

They note that complex changes in the global security environment have heightened the challenge of understanding the security risks of climate change, and they urge creative thinking in seeking solutions. “When it comes to thinking about the impacts of climate change,” they note, “we must guard against a failure of imagination.”

It is encouraging to see the security community calling attention to cross-sectoral linkages and urging practitioners to consider both socio-political and physical vulnerabilities in designing climate change adaptation responses. Such an approach is embodied within “futures analysis,” a field in which the security community has traditionally excelled, and which holds valuable lessons for the development community.

Imaginative thinking in approaching the complex, integrated challenges of population growth, climate change, and security could mean incorporating the perspectives of demographers and social scientists who study the complexities of urbanization in coastal cities and new tools and data that can assist adaptation planners. Such thinking might also assess the multiple push and pull factors that affect migration decisions of farmers, many of them women, attempting to achieve food security under new environmental conditions, and respond to trends that contribute to upward-revisions of population projections in countries that face the greatest food security challenges.

As members of the Military Advisory Board point out, the over-lapping stresses and linked demands that are accelerating the risks of climate change will require “comprehensive” decision-making. Their assessment highlights the urgency of meaningful global action to reduce the greenhouse gas emissions that cause climate change, and also serves as a wake-up call for responding to impacts—particularly the impacts on water, food, and energy that can’t be avoided. “These vital resources are linked,” they note, “and adaptation planning must earnestly consider their interrelationships.”