Climate change will cause dwindling freshwater supplies, food shortages, political instability and other conflicts that U.S. military strategists should be planning for now, several former high-ranking military officials told Congress on Wednesday.
"Our view is that climate change could be a threat multiplier in every global region," Gen. Charles F. Wald, the former deputy commander for the U.S. European Command, told the Senate Foreign Relations Committee.
It's an issue getting more attention in Congress.
Today, the House of Representatives passed an intelligence bill that includes a provision requiring spy agencies to study the impact of global warming on national security.
"It would be irresponsible for us to ignore the warnings of Generals and Admirals who have spent a lifetime on battlefields and who are telling us global warming has the potential to threaten our future security," said Rep. Edward Markey (D-Ma.) in a statement.
Republicans argue the measure will shift intelligence resources away from more important tasks like fighting terrorism.
Witnesses at Wednesday's hearing warned that if nothing is done, a warming climate could lead to an influx of Latin American immigrants to the U.S. border, and could also trigger violent conflicts in Africa and the Middle East over resources, potentially aggravating terrorism.
Wald and two other highly decorated retired military officials told lawmakers that climate change was indeed happening, could worsen many of the causes of instability in the world and should be taken seriously by government.
"I doubt very many people in the military have spent as much time thinking about it as we have, but I think there's a sense that we need to start changing our approach," said Wald.
Retired Vice Adm. Richard Truly, a former astronaut who once headed NASA and the Naval Space Command, said that an ice-free Arctic Ocean could be a new concern for the U.S. Navy -- a battleground of sorts where nations fiercely compete for oil and gas resources once off limits because of the ice.
"That's an example of the type of international issue that will have to be dealt with because of climate change," Truly said.
The witnesses also called for addressing energy policy at home, as well as the nation's reliance on fossil fuels. They urged the United States to begin making serious efforts to develop secure and clean sources of energy to reduce the greenhouse gases that cause global warming.
In addition, they said the United States must work with developing countries, especially China and India, who rely on fossil fuels to feed their energy-hungry economies.
The witnesses at today's hearing are members of a group of 11 high-ranking admirals and generals who released a report last month warning of the national security threat posed by climate change. The study was funded by the analysis firm CNA Corporation.
"Unlike most conventional security threats that involve a single entity acting in specific ways and points in time," the report read, "climate change has the potential to result in multiple chronic conditions, occurring globally within the same time frame."
The study warned of mass migrations and health crises made worse by global warming, which could draw the military into regional conflicts and potentially lead to a greater threat from terrorism, as foreign governments begin to feel the strain of climate extremes.
"When a government can no longer deliver services to its people, ensure domestic order, and protect the nation's borders from invasion," the report read, "conditions are ripe for turmoil, extremism and terrorism to fill the vacuum."
The report also said that hotter, drier and wetter conditions could have a direct impact on military equipment and infrastructure -- stressing weapons systems, bases and overall readiness.
"Operating equipment in extreme environmental conditions increases maintenance requirements -- at considerable cost -- and dramatically reduces the service life of the equipment," the report said.
Military bases at or near sea level could be invaded by rising waters, flooding runways and buildings.
"If key military bases are degraded," the authors said, "so, too, may be the readiness of our forces."
Military planners are taking the threat of climate change seriously, said analyst Peter Schwartz of the Global Business Network. He has authored several climate change reports for the Department of Defense and intelligence community, but was not involved in the CNA report.
"This has moved from the fringe to an important concern," said Schwartz. "These guys naturally take a worst-case view. For example, what are the kinds of worlds of the future that they have to plan for? It influences their choice of technology, their choice of bases and their strategy."
Schwartz said almost every conflict exacerbated by climate change will center on water supplies. He points to the Himalayan plateau in Asia, where global warming is melting the glaciers that feed several major rivers across the continent.
"Two and-a-half billion people depend upon these river systems for water, irrigation, for industry, for their homes, and so on," he said.
Schwartz imagines a scenario in which China could monopolize the flow of the Mekong River, which also runs through five other countries including Thailand, Cambodia and Vietnam.
"This is precisely the kind of thing that can trigger major war," he said.
Now that climate change as a national security issue is getting more attention, government agencies might begin to make clean energy a bigger priority, said Bill Paul, an independent energy analyst who wrote the book "Future Energy."
"With this hearing, they're bringing public attention to what's been known for a long time in private," Paul said.