longtermism
Explanation
This comic satirizes longtermism -- the philosophical view (associated with effective altruism) that we should prioritize the welfare of people in the far distant future.
In the first panel, a longtermist says, "Do you think we should do good for countless people in the far distant future?" and a woman responds, "Sure." The longtermist then reveals they have had nachos for three meals today because it is only two thousand years until the next ice age, so they need to start "living around program requirements for the year 10,000." The woman retorts, "I mean, like, helping the environment," and the longtermist responds, "Didn't we already use that?"
The joke targets the way longtermism can be used to justify absurd or self-serving behavior. Instead of addressing practical near-term concerns like environmental protection, the longtermist character leaps to ridiculously distant timescales (the year 10,000, the next ice age) to justify their current behavior (eating nachos for every meal). The punchline -- "Didn't we already use that?" -- implies they have already exhausted environmentalism as a justification and moved on to increasingly absurd rationalizations. It mocks how grand philosophical frameworks can become detached from common-sense action.