Basically, house cats would take over the world.
In Alan Weisman’s 2007 book “The World Without Us,” the author investigates what would happen if humanity mysteriously vanished from the globe. The world we’ve built would start to decay immediately, though traces of our past would last for thousands or even millions of years.
But we haven’t even touched upon the nuclear power plant meltdowns, buildings being cracked open from the inside, and basically the fact that the entire atmosphere would become a “mini chemical nuclear winter”.