Why Are Interest Rates Discounted?

The time value of money is going to factor in to any big action that you actually undertake to fight climate change because it costs money. So, how are you thinking about the discount rate and like, how much does that traditionally factor into cost benefit analysis for climate change? Yeah, so maybe just taking a step back like why are we discounting these impacts at all? If climate change costs, I think the number's like a quadrillion dollars over the next 100 years. Why are we using this discounting effect? And from a first principle standpoint, interest rates reflect time preference.