Even if you want to save the planet, there's only so much you can do if you are forced to work within the confines of the current system.

The vast majority of the global economy is controlled by private entities. These private entities are also the ones primarily responsible for climate change. Negative externalities don't really hurt the profit margin, and the big guys on top know damn well that even if the world around them burns none of that will touch them. In fact, it might cause their product's price to skyrocket.

Here's the kicker. If you order the businesses to be cleaner, they can just shut down the factories and move production to some crappy third world country desperate for any industry at all. It is more profitable to pay kids pennies to work in a dirty factory than to put in the effort to make a clean factory staffed by well-paid workers. This makes the climate situation worse and it screws over your country.

But it doesn't end there, oh no! The bourgeoisie basically has free reign over who gets elected in liberal democracies. The bourgeoisie has complete control over television and massive influence over the Internet. They are also the only people who have the capital to fund your campaign. Many of these media companies have ties to huge polluters (the Murdoch empire comes to mind). Those that aren't still need to get advertisers, and those advertisers are often not gonna be keen on environmental regulations. What this means is that if your campaign endangers their profits, they will bury you. You can't become a well-known candidate purely through Twitter posts, you know. You need advertisements. You need good press. That only comes from big media companies.

You can't just lie during your campaign to overcome this and then implement climate reforms. Aside from the aforementioned factory closing, there are other things that tie you to the capitalists. You see, a politician's power depends on them. They keep you popular. They are also the people providing your government with weapons. They have to be contracted to build infrastructure. If they don't like you, they can cripple you by refusing to do business with you, or worse, your whole country.

This doesn't even cover all the dictatorships and oligarchies directly run by the people who profit from this.

The trouble is, of course, that getting rid of capitalism and the form of government that enables its rise is incredibly hard and even if by some miracle we pull it off in one country, I doubt we'll ever be able to pull it off everywhere at once. That means whatever we build atop the ashes of the system will still be obligated to interact with its remnants.

I am sorry for rambling. It is late in my current time zone, and I am tired. To paraphrase the great mathematician and awful philosopher Pascal, "had I had more time I would've written a shorter text."