ABSTRACT
Economists who deal with very long-term policy issues, like greenhouse gas emissions over the next century or
two, are nearly unanimous that future benefits that take
the form of additions to future consumption need to be
discounted to be commensurable with the consumption
earlier forgone to produce those benefits. And there is a
near consensus that the appropriate discount rate should
be conceptualized as consisting of two components (Cline, 1992; Manne, this issue; Nordhaus, 1992; Fankhauser, 1993).
