"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."