My guess is that most people would answer that “our own health” is most important. Not because they’re selfish or uncaring about the environment, but because they probably don’t know what’s at stake should our ecosystem no longer be able to sustain us. And they don’t know the most powerful action we can take to promote ecological health.
My answer to the title question is that NOTHING is more important than the sustainability of our ecosystem. That’s because without a healthy ecosystem, our civilization will collapse, making life a hell on Earth for those few of us who survive. And, when that happens, what good is being healthyif we don’t have enough food, water, shelter and clean air?
As for environmental health, most people think it’s a matter of recycling, taking shorter showers, driving electric cars, installing solar panels, etc. All good things to be sure, but only a drop in the bucket when it comes to preserving our ecosystem’s ability to sustain us.