It's not just an issue in "capitalism". Communist countries like the USSR and China have had as bad or worse effects on the environment. It's an issue of humanity.
I don't think it's very helpful to just blame humanity in the general sense without explicitly stating what exactly is fucked up about them (this time). Just like in interpersonal relationships, to fix a problem it's best to focus on single issues rather than ruminate over character flaws.
I'd say that it's an issue of humans wielding industrial strength tools without proper technology for monitoring and constraining resource consumption.
Effectively the planet is populated by autonomous agents focusing on locally optimizing their short-term finances, using capital* to convert landmass and biomass to marketable commodities. The side-effects are as we see.
Now that we have stated the problem, we can actually start figuring out how to limit this. But as economic system design and political action goes I'm all thumbs.
There is a slight reason for optimism. If governments recognize that there is a general action that can be taken then usually a way can be found for global action - and with proper response this actually works. See what happened to the usages CFC:s in refrigerators after it was proven they lay waste to the ozone layer.
Unfortunately the damage to biomass is already extensive. When one kind of food source becomes scarce we can just move to another, without reflecting why did that particular fishery dry up.
With ozone layer the problem was a bit more urgent - "OMFG we are all gonna fry up!".
I'm guessing you're aware, but for other readers this is often called The Tragedy of the Commons. Since nobody's made much headway since it was introduced 50 years ago new ideas are needed.
Thats the honest truth. Its hard when success at conservation and sustainability is directly at odds with nearly every other metric of success we as a species hold dear. Not to say we shouldn't try to make changes, and there's always hope. But its a bit like trying to stop a speeding train while being inside the train and leaning really hard against the wall.
Winning Darwin's game happens to be about dissipating more heat than your competition.
That is almost precisely the statement of the Darwin-Lotka Energy Law (also "the maximum power principle") coined by ecologist Howard T. Odum, based on the work of Charles Darwin and A.J. Lotka:
In its brief form: the maximization of power for useful purposes is the criterion for natural selection.*
Darwin's theory of evolution then becomes a general energy law.
