Rk. Kaufmann, ASSESSING THE DICE MODEL - UNCERTAINTY ASSOCIATED WITH THE EMISSION AND RETENTION OF GREENHOUSE GASES, Climatic change, 35(4), 1997, pp. 435-448
Analysis of the DICE model indicates that it contains unsupported assu
mptions, simple extrapolations, and misspecifications that cause it to
understate the rate at which economic activity emits greenhouse gases
and the rate at which the atmosphere retains greenhouse gases, The mo
del assumes a world population that is 2 billion people lower than the
'base case' projected by demographers. The model extrapolates a decli
ne in the quantity of greenhouse gases emitted per unit of economic ac
tivity that is possible only if there is a structural break in the eco
nomic and engineering factors that have determined this ratio over the
last century, The model uses a single equation to simulate the rate a
t which greenhouse gases accumulate in the atmosphere, The forecast fo
r the airborne fraction generated by this equation contradicts forecas
ts generated by models that represent the physical and chemical proces
ses which determine the movement of carbon from the atmosphere to the
ocean. When these unsupported assumptions, simple extrapolations, and
misspecifications are remedied with simple fixes, the economic impact
of global climate change increases several fold. Similarly, these reme
dies increase the impact of uncertainty on estimates for the economic
impact of global climate change. Together, these results indicate that
considerable scientific and economic research is needed before the th
reat of climate change can be dismissed with any degree of certainty.