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59 In a wide-ranging examination, an NRC panel concluded, "We found no easy answers for institutional change, but many constructive possibilities can be identified." (NRC 1996b), p.325.

60 Miles (1998).

61 cf. Kennedy (1993).

62 As reported in Raskin et al. (1998).

63 See Raskin et al. (1998) for a discussion.

64 This scenario assumes that trends such as those toward more efficient technologies continue. The scenario is therefore not simple extrapolations of current data.

65 Expressed as GDPPPP per capita. In this report, GDP adjusted for purchasing power parity is denoted by GDPPPP, to distinguish it from the more common GDP conversion in market exchange rates (GDPMER).

66 UN (1998).

67 Specifically, hunger lines increase to $3,670, the current inferred value for North America, as mean income approaches $21,880 (the value where the linear fit to the national data intersects the constant line at $3,670). This is analogous to the observation that absolute poverty lines tend to rise as average incomes do (Ravallion et al. 1991; World Bank 1990).

68 IPCC (1992).

69 UNDP (1997).

70 Alternative scenarios can be represented as trajectories in a space defined by three coordinates: the size of the world economy, international equity (ratio of non-OECD to OECD average incomes), and national equity average (ratio of incomes of the poorest 20 percent to the richest 20 percent). The sector of the space over which the scenarios can move plausibly is limited. For example, let us require that both the OECD and non-OECD regions exhibit positive economic growth. Let us also assume that, consistent with convergence assumptions of the scenario, incomes grow faster in non-OECD regions than in OECD regions (implying international equity of income should increase throughout the scenario time frame). Finally, based on historical patterns, let us assume a maximum plausible growth rate of GDPPPP per capita of about 4 percent over the large regions and long time periods we are considering. These plausibility constraints define a possible scenario space. Both the Current Forces and Trends scenario and the Hunger and Carbon Reduction scenario lie within this scenario space.

71 This national equity value would correspond to an average Gini coefficient of only 0.21 in 2025, about two-thirds the current average value in Western Europe. Gini coefficient is a measure of the degree of inequality in a given society. The coefficient is defined with reference to the Lorenz curve, a plot of the fraction of total income held by a given fraction of the population, beginning with the lowest income populations. The coefficent can take values from zero (complete equality) to one (extreme inequality). See Raskin et al. (1998).

72 This corresponds to an average regional Gini coefficient between 0.35 and 0.41 in 2050.

73 IPCC (1996).

74 Rijsberman and Swart (1990).

75 In addition to these energy-related carbon emissions, about 30 Gt C is emitted in the scenario from land changes over this period, mostly due to deforestation. It is assumed that policies for forest sustainability succeed in decreasing net emissions to zero by the year 2050.

76 The patterns of energy-efficiency improvement and energy mix change in Hunger and Carbon Reduction scenario are comparable to the "ecologically driven" scenario of a recent energy scenario exercise of the World Energy Council and the International Institute for Applied Systems Analysis (WEC/IIASA 1995). However, an important difference is that the WEC/IIASA scenario assumes much lower economic growth rates in developing regions (OECD and transitional region assumptions are comparable) so that developing country GDPPPP in 2050 is only half that of the Hunger and Carbon Reduction scenario.

77 See Raskin et al. (1998) for details.

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