Higher temperatures, changing rainfall patterns, rising sea levels and more extreme weather events are predicted to be a formidable foe for the U.S. military as it attempts to meet the challenge of climate change.
Those factors will intensify global instability, hunger, poverty and conflict, the Pentagon said Monday in a new plan, the 2014 Climate Change Adaptation Roadmap.
"Climate change will affect the Department of Defense’s ability to defend the nation and poses immediate risks to U.S. national security," the report said.
In Hawaii the rate of air warming has quadrupled in the past 40 years to over 0.3 degrees Fahrenheit per decade, northeasterly tradewinds have decreased, the state has seen a decline in rainfall over 30 years and sea surface temperatures have warmed, according to a 2014 University of Hawaii Sea Grant College Program report.
On Guam the military is studying a projected increased need for groundwater when climate change might limit the resources available to meet military demand.
Across the globe, climate fluctuations will likely lead to food and water shortages, pandemic disease, disputes over refugees and resources, and destruction by natural disasters, the Pentagon said.
"A changing climate will have real impacts on our military and the way it executes its missions," Defense Secretary Chuck Hagel said in a foreword in the new Pentagon report. "The military could be called upon more often to support civil authorities, and provide humanitarian assistance and disaster relief in the face of more frequent and more intense natural disasters."
Coastal installations are vulnerable to rising sea levels and increased flooding, while droughts, wildfires and more extreme temperatures could threaten many training activities, the Pentagon said.
Last year the Defense Department released an Arctic strategy addressing potential security implications from international claims to the resources-rich area that is increasingly accessible with rapidly melting sea ice.
Adm. Samuel Locklear III, head of U.S. Pacific Command at Camp Smith, said last year that climate change was the biggest long-term security threat in the Pacific region.
Significant upheaval related to global warming "is probably the most likely thing that is going to happen … that will cripple the security environment, probably more likely than the other scenarios we all often talk about," Locklear told The Boston Globe.
Locklear noted that in the not-too-distant future is the real potential of some nations being displaced by rising sea level.
In testimony before the Senate Armed Services Committee, Locklear said between 2008 and 2012, 280,000 people in the Pacific region died due to natural disasters, about 800,000 were displaced and $500 billion in productivity was lost.
The Pentagon said one of its first steps in planning for projected climate change is a "baseline survey" — almost completed — to assess potential vulnerability at more than 7,000 military bases, installations and other facilities.
"We are considering the impacts of climate change in our war games and defense planning scenarios, and are working with our combatant commanders to address impacts in their areas of responsibility," Hagel said.
Climate change predictions remain controversial. President Barack Obama said "the debate is settled. Climate change is a fact," in his January State of the Union address, but the actual outcomes for the remainder of this century remain unknown, scientists say.
The American Association for the Advancement of Science said based on the evidence, about 97 percent of climate experts have concluded that human-caused climate change is happening.
Carbon dioxide is the primary greenhouse gas emitted as a result of human activities, and as emissions continue and warming increases, the risk increases, according to the association.
Earth’s climate is on a path to warm beyond the range of what has been experienced over the past millions of years, the association said.
The latest National Climate Assessment, meanwhile, said global sea level has risen about 8 inches since reliable record-keeping began in 1880, and it is projected to rise another 1 to 4 feet by 2100.
"While scientists are converging toward consensus on future climate predictions, uncertainty remains," the Pentagon admitted. "But this cannot be an excuse for delaying action. Every day, our military deals with global uncertainty."
The military said it is studying the implications of increased demand for the National Guard in the aftermath of extreme weather events.
"We are also assessing impacts on our global operations — for instance, how climate change may factor into our rebalance to the Asia-Pacific," the Pentagon report said.
