> A better argument for solar panels is that per kwh of useful energy, a solar panel traps less solar energy (in kwh) than the CO2 produced by coal or gas or w/e.
It's not a better argument because the solar panel doesn't "trap" the energy. At most it borrows it, eventually it will radiate back out if allowed to do so, just as it would if it were absorbed by a rock. Humans do not occupy enough of the surface of this planet to make a dent in that.
The thing that will keep it from radiating back out is greenhouse gases in the atmosphere. And unlike some brief capture of energy, the greenhouse cycle is essentially a chain reaction.
But it is radiating it 'back out' less efficiently than a white roof. Thus black solar panels may indeed be a net negative if every building otherwise would have had a white roof.
In a land of mostly dark roofs it's probably a net positive.
Unless you pump the energy deep in to the ground it will still eventually find its way to radiate back out in the form of infrared blackbody radiation. The timescale we're talking about isn't very long in the grand scheme of things, and the entire surface of the planet is doing this to some extent or another.
Even if we did one of those megasolar projects people like to talk about like paneling the whole Sahara or Mojave, we would still only be absorbing a tiny amount of the petawatts per second the sun is constantly bombarding the planet with, much of it being absorbed by plants, the ocean, darker rocks, etc.
Our solar panels just don't hit the scale that the melting ice caps do, and the only thing we can do to stop that is reduce the flow of new ghgs into the atmosphere.
It's not a better argument because the solar panel doesn't "trap" the energy. At most it borrows it, eventually it will radiate back out if allowed to do so, just as it would if it were absorbed by a rock. Humans do not occupy enough of the surface of this planet to make a dent in that.
The thing that will keep it from radiating back out is greenhouse gases in the atmosphere. And unlike some brief capture of energy, the greenhouse cycle is essentially a chain reaction.