Global environmental issues - like biodiversity conservation or climate change - are in reality long term issues that are not properly taken into account with traditional models that incorporate the impatience axiom manifested in fixed discount factors and in the use of present discounted...

I review the complex welfare economic issues that arise in environmental decision-making over very long periods, as in cases relating to climate change and biodiversity loss. I also consider the issues that arise in choosing a discount rate to apply to very long-run projects and indicate how...