In March, the Pentagon’s Quadrennial Defense Review, the agency’s main public document describing the current doctrine of the United States military, drew a direct link between the effects of global warming — like rising sea levels and extreme weather patterns — and terrorism.

“These effects are threat multipliers that will aggravate stressors abroad, such as poverty, environmental degradation, political instability and social tensions — conditions that can enable terrorist activity and other forms of violence,” the review said.

Tuesday’s report is an update of a report by the center’s Military Advisory Board in 2007, the first major study to draw the link between climate change and national security. The report’s authors said the biggest change in the seven years between the two studies was the increase in scientific certainty about global warming, and of the link between global warming and security disruptions.

The 2007 report also described climate change as a “threat multiplier” or a problem that could enhance or contribute to already existing causes of global disruption. The 2014 report updates that language, calling climate change a “catalyst for conflict” — a phrase intentionally chosen, the report’s authors said, to signal that climate change is an active, driving force in starting conflict.

“In the past, the thinking was that climate change multiplied the significance of a situation,” said Gen. Charles F. Wald, who contributed to both reports and is retired from the Air Force. “Now we’re saying it’s going to be a direct cause of instability.”

The most recent scientific reports on climate change warn that increasing drought in Africa is now turning arable land to desert. The national security report’s authors conclude that the slow but steady expansion of the Sahara through Mali, which is killing crops and leaving farmers starving, may have been a contributing force in the jihadist uprising in that African country in 2012. Since then, Al Qaeda in the Islamic Maghreb has seized control of northern Mali and remains in conflict with the Malian government.

The report warns that rising sea levels in the United States imperil many of the Navy’s coastal installations. Last week, the White House released a National Climate Assessment report citing Norfolk, Va., as one of the cities most vulnerable to damage by rising sea levels. Norfolk is home to the world’s largest naval base as well as a nuclear submarine construction yard — all of which are vulnerable to destruction by rising sea levels, found in Tuesday’s report.