When one can't help by being on the inside, it is sometimes better to go outside so that one can better use this one life that one gets.
Also, continuing to work there and complying with their new-speak policy while waiting for the axe to fall (3200 cuts planned at the EPA according to the NYT) might be seen as endorsing this adminstration's policy.
“I don’t go home pissed off every night” might be viewed as making things better. Hey, the American public put these yahoos in charge, why does that become my problem?
I think that climate change is probably he most likely possible cause of human civilization collapse, with accidental nuclear war in a close second place. It’s a shame that the current administration obviously doesn’t see things this way.
They're old, they'll be dead before any serious consequences for climate change are realized. The whole system rewards politicians for short term gains that may have terrible long term results because humans generally suck at making sacrifices for long term benefits that ttey themselves won't realize vs. taking the instant gratification route. Maybe the next species that replaces us will be marginally better than we are, assuming we don't annihilate them all when we kill ourselves.
Not to diminish the threat, but I think the impact of climate change on human civilization is often overrated. Countries most affected will include India, Bangladesh, Indonesia... none of them in the modern global powers. What I expect 50-100 years from now is:
In most affected countries, mass precarity, mass migrations, hardening of borders, end of the relative post-WW2 world peace.
In Europe/USA, flooded areas will be evacuated/relocated. Living conditions will worsen as a result of the end of globalization.
In Russia/Greenland/Canada, warming temperatures will create more temperate areas. This will create new economic hubs, and the economic growth paradigm will prevail. Business will continue, and conditions will worsen for another 100 years.
After that, a sizeable portion of Earth will be unfit for humans, and human population will have decreased a great deal. But no end of the human race visible for now.
I think that (and I don't mean to argue that you think this these are OK) "a sizeable portion of Earth will be unfit for humans, and human population will have decreased a great deal" is a pretty terrible outcome. Those people will be starving to death, dying in migration related conflicts, or choking to death on wildfire smoke. Not pretty. You're right, it may not cause civilizational collapse, but I find those other outcomes totally unacceptable and we ought to be doing more about it right now.