https://www.livescience.com/65698-defense-department-climate-change.html

86 million barrels/year 2016 for operational purposes means over 4 trillion dollars. If we add the cost/hour of hiring the military airplanes for the global coverage, a half of the approximate number of unregistered global flights, salaries of all pilots, insurances, the wages of the craft personnel, you will get an astronomical cost for something Nature was doing for free, with far less extreems and without polluting the planet, its atmosphere and habitat.

Globally:  A primer on weather and climate intervention for economists:

https://www.ifo.de/DocDL/cesifo1_wp7586.pdf 

To refresh the history- the UN opened The Convention on the Prohibition of Military or Any other Hostile Use of Environmental Modification Techniques for signature in May 1977..the UN made it clear that
intending to harm others through deliberate manipulation of the environmental processes by any state was an
unacceptable and inappropriate use of these emerging technologies.

That was 40 years ago.