Don't worry, US citizens will let it.
USAID, dead. IRS, gutted. FBI & DHS, nazified. The list goes on into the hundreds maybe thousands.
If US citizens changed things today, it would still be decades upon decades before one could even get back to square one.
It sucks, but at this point I think China taking over as the world's super power might be net better in the short term.
A generation? No. All future generations.
What future generations?
The venn diagram's circle of 'no' in inside that of 'all'.
Not only would it cost America a generation, each country, each area under the American influence will suffer the same.
Climate
Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.
As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades:

How much each change to the atmosphere has warmed the world:

Recommended actions to cut greenhouse gas emissions in the near future:

Anti-science, inactivism, and unsupported conspiracy theories are not ok here.