[…] recognize that at least in terms of sheer numbers, the current population is easily outweighed by all those who will come after us. In a calculation made by writer Richard Fisher, around 100 billion people have lived and died in the past 50,000 years. But they, together with the 7.7 billion people currently alive, are far outweighed by the estimated 6.75 trillion people who will be born over the next 50,000 years, if this century’s birth rate is maintained (see graphic below). Even in just the next millennium, more than 135 billion people are likely to be born.~ Roman Krznaric from, https://blog.longnow.org/02020/07/20/six-ways-to-think-long-term-a-cognitive-toolkit-for-good-ancestors/
50,000 years is somewhat of course. But it’s a good estimate of the span so far of recognizably-like-current-us human history. It’s obvious that today, most people are already dead. It’s those trillion yet to come that warp the brain and create perspective.
This article from The Long Now Foundation has 6 good examples of explicit ways to think long-term, rather than short-term.