Welcome to the ******* Dark Ages.
The American Rightwing has devolved to the point where they are forbidding our Military Services from integrating climate science into their models.
Droughts, melting ice caps and mega-storms have a huge impact on planetary life and resource competition, but the OP heard on Fox News that we should only consider the Bible when building scientific models.
How the **** did we get here?
Tell us how your mythical scenario will impact battle plans with Iran.
Climate induced migration can magnify tension in the world - especially if it involves the collision of different ethnicities and religions. Also... climate changes can cause access problems to water/food, which again can absolutely cause global tension.
The role of our defense agencies is not simply to assess the Iran threat but to assess any/all potential global problems that can result in human conflict/national security threats (short and long range).
This means our defense agencies also look at things like population growth in 3rd world countries, which itself increases migration pressure to the west (which amplifies ethnic tensions as say whites and Muslims are forced into compressed spaces. Adding a climate variable to this is reasonable when such a variable influences migration and resource competition).
The reason to build long range models of climate based migration & resource competition is that more information about global migration and resource access/competition is generally considered to be better than less information.
Consider what happened in the 70s when it was predicted that US Oil supplies were at their peak. Reagan's defense team, by the 80s, was well aware that the Middle East - based on scientific models of remaining LARGE oil fields - was going to become ground zero for resource competition. This finding was not only vital to our economic survival, but it set the context for the coming global conflict (between the west and Islam). So of course, the Pentagon has scientific models for assessing all the variable that affect access to energy.
FYI: your views & mine are closer than you think when it comes to the idea of "fighting climate change." Even if human activity was amplifying these changes (which I know you don't concede), I believe any government-lead intervention would make things worse. Any attempt to limit carbon emissions must be market based. It must be affordable for Byers and profitable for suppliers, otherwise we will lack the incentive structure for doing it.
However, when it comes to merely creating scientific models for evaluating global migration & conflict patterns, I'm for more rather than less information. Respectfully.