But a number of U.S. intelligence and military studies recently made public describe how man-made climate change plays into the hands of terrorist groups in many countries -- and specifically, aggravates the war in Afghanistan by giving a boost to the Taliban and its al Qaeda allies.
The studies detail a number of ways in which global warming is creating new headaches for the U.S. military around the world.
"National Security and the Threat of Climate Change," with essays by 11 U.S. generals and admirals, published by the CNA Corp., was supervised by the former chief of staff of the U.S. Army, Gen. Gordon R. Sullivan.
Like the other studies, it details how terrorist groups often are helped global warming's increasing droughts -- especially in poor countries.
"Probably, the poster child is Somalia," Sullivan told ABC News. "Famine created by drought [leaves many people] ripe for picking for terrorist groups."
"The Somalis who needed foodstuffs went to Kenya and Ethiopia," he said, "and the warlords stayed in Somalia."
Sullivan, like other military analysts, found similar patterns in many countries: "The headwaters of the Jordan are found up in the mountains of Northern Syria and Turkey, the Middle East, an already volatile area -- tinder boxes. Global climate change could be like striking a match around an open can of gasoline."
Sullivan and other authorities say drought has been aiding the Taliban and al Qaeda terrorists in Afghanistan for some time.
"[It's in] the conflict over water, crops," he said. "Afghanistan ... has an agricultural economy, but is not robust and a lack of water would be devastating."
Afghanistan is now 11 years into a drought with no end in sight. Scientists say it fits the pattern long predicted for global warming, and matches similar climatic changes in other mountain ranges around the world -- including California's Sierra Nevadas, which provide annual melt water irrigating America's fertile San Joaquin Valley.
Snows have been vanishing for more than a decade from Afghan mountains that used to pour melt water throughout the summer down into orchards and fields.
Afghanistan used to be a food exporting country, famous in the region for its fruit and raisins. Now, large portions of Afghans survive on foreign food aid.
With much of Afghanistan's ancient irrigation system already shattered by years of war, agriculture in the predominantly rural country is struggling, leaving many young men with no money or work.
"There are a lot more people -- young males -- who are unemployed with nothing to do, and so the Taliban basically seems an attractive thing for them to join," says Arian Sharifi, who worked with ABC News for several years there, and more recently worked in the Afghan government.
"The Taliban pay the fighters," said Sharifi, who is now a graduate student at Princeton University's Woodrow Wilson School.
Global warming also helps the Taliban and al Qaeda in two other ways, he said.
"When people's economic situation is good, they tend to be happy, and when they are happy there are not a lot of things wrong with the government," said Sharifi, referring to pre-drought times when the agricultural base of his country's economy was flourishing.
"But when they are not happy economically, then they tend to be disenchanted with the government," he added, "so it sort of creates a mindset for the people that the government is not creating and providing a lot of basic services for the people -- therefore the Taliban must be the alternative to the current government."
The other global warming factor involves the extensive poppy farming that is making the Taliban and al Qaeda very rich, according to a number of studies.
The drought-resistant opium poppies that feed a booming heroin trade, say Sharifi and a number of other authorities, are making the Taliban and Al Qaeda very rich.
The Taliban encourages and taxes the poppy crops, notably in southern Afghanistan's Helmand province.
Because poppies, unlike the other traditional Afghan crops, need little water, many farmers say they're now growing them simply because there's little other choice in the lengthening drought.
Taxes levied by the Taliban are earning it and its al Qaeda allies an estimated $500 million year, according to Gretchen Peters, author of "Seeds of Terror: How Heroin Is Bankrolling the Taliban and al Qaeda."
"One of the main reasons the farmers give [for growing poppies] in survey after survey is that years of war and years of drought have destroyed the irrigation systems; they just don't get the water that they need for other traditional crops," said Peters, who travelled extensively for more than 10 years throughout Pakistan and Afghanistan while reporting for ABC News.
"When the Marines arrived in Helmond," she said, "the villagers would meet with them and say, 'If you'll protect us and fix our irrigation systems, we'll stop growing poppy and we'll ally with you instead of the Taliban.' There's an absolutely direct link between the two issues."