>>130191996They're no threat then.
They'll burn the oil, raise the CO2 content, and die of global warming.
After all, there's nothing removing CO2 from the air.
The entire planet is a single city and armaments factory.
(Which raises the question of what they eat. Though
>>130191911 already addressed that.)
Seriously, I read a series recently where the villains regard other intelligent races as "food". They strip-mine worlds and fleets of thousands of carriers tote off the material to construct a Dyson Sphere around their home star. Each carrier can lug a few cubic miles.
A little arithmetic showed that all that effort would have reduced the diameter of an Earth-sized planet by less than an inch.
They're a hive-species and can't live alone or in small groups so they can't colonize other worlds. Hence, the Dyson Sphere. As soon as I read that I knew how the series was going to end in the next book.
