I think pollution from warhead explosions is still negligible compared with pollution from fires or created from the emissions in reconstruction destroyed buildings or perhaps even the supply chain of delivering the warhead. The US and China military transport emissions probably dwarf everything.
The assumption that military activity, which is a subset of any nations economy and mostly stationary in any case but a world war, would not be dwarfed by the majority of civilian activity like industrial activity and trade routes, is simply absurd.
There is nothing about “military engines” or “military supply routes” or “military explosions” that leads anyone to believe their impact would be any worse than their civilian equivalents, and even if they were, you still have to prove that they are so much worse that even their limited activity compared to the normal economy must be given priority attention.
The burden of proof is on the one making the claim, not everyone else.
It's a fair argument, an active war is more intensive on emissions (tanks, trucks, planes, trains if not electrified need fuel, and especially older Soviet-era models aren't known for the fuel or emission efficiency).
Expand your search, and be amazed by how many wars are and have been fought, always, continuously, and forever.
When you're done with that search, look up volcano explosions on land and under the sea, and compare them to the explosive power of a missle.
When you have a bleeding cow, you can solve the bleeding issue and keep the cow alive, while completely ignoring the mosquitoes "relentlessly draining" its blood.
I have quickly googled that statement and all I see is pre-02/24/22 data. I am sure the percent has changed significantly from the good old times.