Sure, I believe it's useful in that rich western countries continue their leisurely transition to cleaner energy as it becomes cheaper, combined with gas taxes and carbon trading and such. Billionaires investing more money in cleaner energy can be marginally beneficial, though there is already large and increasing amounts of capital allocated by the markets toward this end.

But the deciding factor is can we make everyone stop using the cheap fossil fuels that are basically free money lying in the ground. Oil price will follow demand. It might get cheaper if western countries cut consumption, but someone will still buy the rest with the lower price. And there is nothing in the horizon that would displace oil and coal at their minimum profitable production prices for developing countries (where most people live) in the requisite timeframe. If we leave it to markets, this is the case by overwhelming odds, Zuckerberg or no Zuckerberg.

Think what needs to happen on the world stage in order to enact a global ban (1) on oil pumping and coal mining within 20 years. That's the job. Interests of nations addicted to the oil income, interests of nations whose agriculture is entirely dependent on cheap imported oil, etc. Easy UN consensus?

And this is just the energy sector, there's more to climate change drivers. So fixing this is necessary but not sufficient. The same political measures that are needed to coordinate the energy sector will also work for the other sectors. But energy tech won't.

(1) A very high tax really, that 99% prevents use in fuel applications. Ban is a simpler word.

edit: added bit about fossil prices reacting to demand in west

> "Think what needs to happen on the world stage in order to enact a global ban (1) on oil pumping and coal mining within 20 years. That's the job."

You could aim for that, or you could aim for a steady stream of improvements leading to larger change once momentum is built. Or in other words, revolution vs. evolution. If you want to pursue revolution, go for it, I'll continue to pursue evolution.

Are you uggesting we don't have give up fossils that quickly, or are you suggesting we could wait 19 years and then shut down fossil fuels with a large change which would bring cheap fossils replacements for even third world countries?

I do favour ramping down incrementally, and we should get started ASAP.

I'm suggesting that instead of waiting for dramatic political and/or economic changes I will support every opportunity we get to move in the right direction, regardless of how small those changes are. The key in my opinion is building momentum. Research into clean technologies are likely to pay off eventually, even if the changes in the near term are negligible.

Remember that the best way to predict the future is to invent it. If you truly want your revolution, then lead the way by action. I'll continue supporting change in my own way.