I'm glad most of these problems can be solved by small lifestyle choices, and that by consuming slightly differently as an individual, I can have faith that I'm personally preserving the world for future generations. And once people see the profoundly ethical consumption choices I make, they'll start to follow suit, and there'll be a massive ripple effect centered around my consumption that spreads across the whole world as people switch to paper bags and only eat meat three days a week. If people's choices were influenced by their material environment rather than the spread of ideas, we'd be forced to think of ways to change their material environment, which seems a lot harder than just changing people's minds.
I'm glad that most of this impact is caused by individuals and their consumption habits, because it's easy to convince people to consume differently. If these problems were disproportionately caused by corporations, governments, and militaries, then we'd have to change their minds, and they can't be simply talked into acting differently. There'd have to be some risk to their bottom line or material interests, perhaps some sort of immediate threat to the people in charge, which would be difficult for individuals like us to enact within the bounds of the law and pacifist social norms.
I'm glad most of us live in some form of democracy where we can vote for initiatives and people who will address these pressing issues. Voting is more important than ever because of this.
In a hypothetical world where this weren't the case (say elected representatives had shown a long track record of ignoring the demands of their constituents and brushing these kinds of problems under the rug, for instance) it would unfortunately be our ethical duty to take matters into our own hands with more radical action. Since politicians would value the profit of fossil fuel corporations more than our well-being and the world's future, we'd have to find some way for individuals to impact the bottom lines of these companies, possibly by drastically increasing the cost of doing business, perhaps by increasing the cost of maintaining their machinery somehow. But I'm glad I can just vote for people who can be trusted to use their state power to solve these problems peacefully and legally.
No sarcasm here. I'd never recommend people do anything illegal, especially on a public internet forum. Like I said, voting and baby steps are already good solutions to impending global catastrophe.
Not only is voting and individual life-style changes good solutions to impending global catastrophe, you would also be a racist and/or sexist, for suggesting that those approaches aren't good enough. Not to mention ableist for suggesting that maybe the status-quo isn't something that should be upheld.