Figure
3 The effect of assumed technological
advances on the course of CO2 emissions
and concentrations through the next 100 years. The blue, steeply-rising
curves show what would likely ensue were the energy technology that
is employed, worldwide, to be restricted, on average, to what is
available today . The black curve, from Figs. 1 and 2, is IPCC scenario
IS92a, which assumes drastic changes in how electricity is generated
and used. The dashed blue lines, for comparison, are emissions and
concentrations paths consistent with a goal of holding the eventual
CO2 concentration below a ceiling
of 550 ppmv (about twice the pre-industrial level.)
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