The next WW will probably be Biological and the world will probably not even know what hit them.
How about a nice airborne/waterborne pathogen designed around DNA of those of Prominent middle eastern descent that simply renders them sterile.
The next ‘nuclear’ weapons will be Genetically modified DNA (is that redundant?) designer diseases.
Romans used to salt the earth and catapult diseased sheep (anthrax) into and around people they didn’t like. We aren’t so different. Just the methods have changed.
Only extreme crazies screw around with bioweapons.
Unfortunately, there are extreme crazies out there.