Solar energy almost won

I was watching Cosmos last night. In episode 12 it addresses atmospheric carbon dioxide. Several interesting and daunting facts are presented:
1. There's no question warming is due to the level of CO2 in the atmosphere.
2. The CO2 levels are unprecedented in all meaningful historical contexts.
3. We produce orders of magnitude more CO2 than all the volcanic eruptions on the Earth, combined.
4. There's an easy-to-describe positive feedback loop contributing to the warming:
   a. Higher CO2 leads to higher heat.
   b. Higher heat leads to polar ice melt.
   c. Less polar ice means less highly reflective surface, leading to more retained solar energy.
   d. More retained solar energy leads to even higher heat, resulting in more [b].
5. The arctic tundra/ice has as much frozen organic material locked up as the total carbon currently in the atmosphere. If that starts to melt and the material essentially rots and is released, we get more [4.a]. This scenario is likely "catastrophic and irreversible".

So how did we get here? The culprit is really the invention of the engine. Before the engine, our primary carbon emissions were firewood and cow farts. The engine lead to widespread automation of mechanical tasks. A machine could be built once, then supplied with an energy source to produce way more work than any human is capable of. Humans started doing meta-work: they built the machines, which could then be leveraged to do energy-consuming tasks and to build other machines. In this way, we can essentially scale to arbitrary energy consumption capability. The only limit is how fast we can collect energy sources.

The particulars of the engine design were such that motion is driven by expanding gas. The first design (steam engine) used gas pressure to drive fan blades attached to a wheel. The gas is steam, and is created by heating water. The heat comes from burning coal. The design, in some sense hasn't been updated since. The internal combustion engine is the same concept, just substituting a self-contained piston for the wheel blade, and generating gas pressure through the direct explosion of an air-and-carbon fuel mixture. Even our mighty nuclear power stations use this approach; they just use nuclear reactions instead of burning carbon to produce the heat (hence why they are, in at least this dimension, much cleaner). However, this leads to a natural question: why, if the heat doesn't have to be carbon-powered, did we end up using carbon (and still are using it) as the primary source?

The easiest reason is that carbon is plentiful, distributed around the world, energy-dense, and highly portable. No special engineering is needed to store it or distribute it. Refilling a train with coal or a car with gasoline is a snap. Each can carry enough fuel to cover meaningful distances. We simply didn't have (and still are in the early stages of developing) other energy sources that fit the above criteria. Electric cars, for example, are becoming more common, but they are still limited in their role and convenience. And, if a solution is adequate and incrementally improvable (energy efficiency, mining efficiency, ...) and there seem to be no fundamental concerns, why change?

It turns out, we could and should have seen all this coming.
A 1932 paper by REO Hulbert described the theory of climate change due to atmospheric carbon dioxide change. And a 1938 paper GS Callendar actually called out observed warming (though he actually argued that they were a good thing because crops could grow over a wider range of latitudes). You read a thorough history here. And, we knew as far back as 1896 that doubling our atmospheric carbon dioxide would melt the polar ice.

And think, if not for chance discovery of lots of North African oil, solar power may have taken off a hundred years ago.