This is a linkpost for Shelly Kagan's Ethics and the Future readings
Cowen, Discount Rates Table, Stubborn Attachments (1 page)
gives a quick sense of how even a “modest” discount rate effectively wipes out the significance of the long term future.
Parfit, Reasons and Persons, Appendix F (7 pages)
for arguments against the social discount rate.
Other topics to check out
Expected value of the future
Expected value of the future
Is the expected value of the future positive or negative? A crucial consideration for the value of extinction risk reduction.
Existential Risk
Existential Risk
What is an existential risk and what is the case for treating them as a moral priority?