Figure
4 Total costs of holding global
CO2 concentrations below eventual
ceilings of 450, 550, 650, and 750 ppmv, and the reductions possible
through assumed advances in energy technology. The higher set of
stepped blocks at the rear of the figure give calculated costs when
technologies employed in electric power generation and use are limited
to what is used today. The lower set of costs, in front, are based
on the technological advances that are assumed in the projections
of IPCC scenario IS92a. Costs are in percent of the present discounted
global gross domestic product (GDP), which in 1995 was approximately
$19 trillion.
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