> Let's combat global warming by producing even more heat, converting 40% of it to electricity.
All the wattage produced by humanity is utterly insignificant in the face of the energy we receive from the sun. It will still be insignificant if we double it.
(We receive about 2 × 10^18 watt hours per day from the sun at the ground. Daily human energy production is about 5 × 10^15 watt hours.)
In addition, it may be possible to put surplus energy into atmospheric greenhouse gas fixation, if such technologies are fruitful. In essence spending more watts to reduce future retention of solar thermal joules.
> (Now consider that in the golden age of oil before the oil shocks in the seventies, oil consumption was growing more like 8% per year.)
At that time, per capita energy use in the US was growing by 3% per year while population would grow by 1.5% per year. Today, per capita energy consumption in the United States is falling, and the population is growing more slowly. The story is much the same elsewhere. Even China has leveled off in per capita energy consumption. India's is still growing, but it will take many years considering their baseline of 1/10 of the United States per capita before they're the biggest problem, and I guess they'll probably turn that trend around before they actually get to that point.
In that scenario, we are doomed anyway: If we would generate anywhere close to that level of power via solar, we would change the albedo of earth significantly -> heating. And we would certainly affect the air currents on a global scale if we use wind power to that extend.
Assuming widespread deployment of fusion reactors and use of battery powered vehicles for transport, humanity's carbon footprint would decrease by about one or even two orders of magnitude, which is the real culprit behind anthropogenic climate change. Obviously that's not something that can happen overnight.
All the wattage produced by humanity is utterly insignificant in the face of the energy we receive from the sun. It will still be insignificant if we double it.
(We receive about 2 × 10^18 watt hours per day from the sun at the ground. Daily human energy production is about 5 × 10^15 watt hours.)