چکیده:
Evaluating the economic consequences of the climate change, as well as assessing the environmental economic policies associated with it, requires a good understanding of both natural and socio-economic processes. Specific models, named Integrated Assessment Models, are used to this purpose. The idea behind the IAM models is relatively straightforward (in theory): climatologic sub-models get information about human-induced greenhouse gas emissions from economic sub-models, simulating levels of economic activity, whereas information about climate and temperature changes are used as an input in the determination of economic scenarios.
As a matter of fact, the economic side of currently available IAM models suffer from two main drawbacks. First, the description of the world economic structure is often too simplistic: limited number of industries (sometimes only one good, available for both consumption and investment), poor or absent description of international trade and capital flows (Manne et al. (1995), Nordhaus and Yang (1996)). Second, the multi-dimensional nature of the impact of the climate change on the economic systems is disregarded. This is usually accommodated by specific ad-hoc relationships, making a certain fraction of potential income “melting away” as temperature increases. Not surprisingly, key parameters for these equations are often estimated in rather mysterious ways.