Here is what monied capitalists most fear: If climate change is real, either free market capitalism dies or a sizable of chunk of humanity does.
Uhm, what?
Since when was Elon Musk not a capitalist? I'm pretty sure he's charging real money for Tesla Model Ss and Powerwalls. I'm pretty sure SolarCity isn't giving away solar panels for free. I'm pretty sure the Model X will go on sale this year, and people will give him money and he will give them a car in return.
Capitalism is not incompatible with environmentalism. It's just that there are entrenched interests in our current capitalism that make money in ways that are incompatible with environmentalism. Elon Musk is a disruptive capitalist who is going to make several more entrenched interests very unhappy by the end of the decade. He's already making some entrenched interests (notably United Launch Alliance) very unhappy in non-environmentally related fields. (They're having to spend money on those horrible horrible professional middle class people to get them to design a better rocket for the first time in two decades, instead of just selling the same old piece of shit for sweet cost-plus contracts.)
As of today, if you have the capital, you can give Elon Musk money and he will give you equipment that can cut your personal carbon footprint by 36%, permanently, by wiping out your emissions for housing and travel. That 36% is fully half of the footprint that you personally control. This is a transaction in a capitalist system, where the means of production are privately owned, rather than government owned, where the organization doing the producing expands its production capacity and research and development efforts using private profits, and where the purchaser has a choice of viable alternatives in some sort of market.
The US economy has been capitalist for over 200 years, and it has been getting more environmentally friendly for that entire period. Admittedly it started out rather thoroughly unfriendly, so there was a lot of room for improvement, but it has happened. Nor were the changes voluntary, but they still happened, while still being fundamentally capitalist.