Pain. Pain on the personally detectable level, and someone they trust to explain to them why they’re hurting. As it stands now few people feel that pain, and if they do, there are legions of smug pricks telling them tall tales about the cause. If the Arab “Spring” and subsequent crises had been clearly and accurately framed as an environmental issue first, people would be freaking out. Instead it’s gotten every kind of spin short of the reality of drought leading to skyrocketing food costs in depressed economies.
It is fairly easy to see this and some portion of people see it immediately. Unfortunately, another who profit from these things ask "what does it take for people not to see and stop these things?" and the answer is fairly visible in the way global warming has been [not] addressed.
While I agree in general, in this particular case, technology and markets today are trying to get more people onto less land and in arrangements that require less energy. Current public policy is holding it back.
Global capital is overall profit-prioritizing, externalizes tons of costs, invests massively in lobbying governments for their interests, and focuses on relatively short-term growth figures.
It sounds like you are suggesting that if only grassroots push-back would go away, global capital is generally solving ecological problems. I hope that completely backwards view isn't what you're actually suggesting.
Maybe you are talking about knee-jerk anti-density, anti-development stuff? While that NIMBYism is a real problem, and there are real developers working in the right direction, we still have far more global capital and power behind fossil-fuel companies and pesticide manufacturers etc. than behind sustainable-development tech. Despite all the push for electric vehicles, car companies are pushing way-oversized usually-single-occupant vehicles (SUV's and pickup-trucks-that-people-use-just-for-commuting and such) as much as ever, and lobby for all the unsustainable public infrastructure for them…
At any rate, the org doing the best at combating both the unsustainable and corrupt capital growth-focused nonsense and the counter-productive NIMBYism is https://www.strongtowns.org (not sure what the best equivalent is for issues around pesticides and healthy biodiversity).
Global capital is generally responding to consumer preferences, which in the context of housing means high-density structures in walkable and transit-connected areas, which are specifically good. Consumers also have lots of un-ecological preferences, like large vehicles, cheap meat, etc. which are not.
>unsustainable public infrastructure
Car infrastructure is problematic in many ways, but "unsustainable" is the wrong word. We're sustaining it just fine, unlike its alternatives. Empirically, our most important transit systems are incapable of maintaining previously-achieved levels of service for any amount of money, and the costs of implementing new service are escalating for reasons we don't understand such that even minor subway buildout is becoming an existential challenge to the resources of our richest and fastest-growing cities. Give it 30 years, and it's not clear that the collective productivity of all humanity will exceed the cost of a mile of New York City subway track. That's unsustainable. The environmental-friendliness axis is orthogonal.
Pesticides and population growth expanding into more and more territory helped a lot of human problems in the past, but created new problems. Expanding into new territory escaped problems of poisoning, desertifying, or overfilling the land . . . until we populated the whole planet and the environment reached toxic levels of pollution.
You might say the environment isn't yet toxic to us (though some places are), but it appears so for some essential symbiotic life. If experts in the field don't know what's happening, then people who estimate carrying capacities for the planet don't either, raising the error bars downward for their estimation.
Systems perspectives predict outcomes like this and suggest systemic solutions, not technology or market solutions alone (though they are important), which are likely exacerbating them. A key leverage point I see are they system's beliefs and goals. They're hard to change, but such changes have happened before.