Emissions Scenarios - IPCC

94 An Overview of the Scenario Literature
35
1950 2000 2050 2100
Figure 2-5: Gross world product - historical development and 193 scenaiios, shown as an index (1990 = 1). Data source:
1993a, 1993b; Morita and Lee, 1998.
UN,
For 2050 most of the scenarios cluster in a rather narrow range
around a value of about US$100 trillion. In total, 166 scenaiios
were used to derive the histogram for 2050. This picture
changes radically for the year 2100, with a very wide variation
of gross world product values, from about US$700 to US$70
trillion, and a median of US$250 trillion. As expected, the
distribution of emissions becomes significantly wider as the
scenarios extend further into the future. Most of the
distribution is concentrated between about US$320 and
US$160 trillion, with very thin and asymmetric tails. A very
strong peak of values lies at around US$250 trillion, which
apparently represents an apparent consensus among modelers
based on an average economic growth rate of about 2.3% per
year. The frequency of the mode is smaller in 2100 than in
2100
IS92 a, b
N=148
Mean=248
Range (index, 1990=1)
I I l-l—1_LJ U I I U U LJ_
oooin ООО oo о о oo oo oo
Figure 2-6a: Histogram showing frequency distribution of
gross world product in 2050 for 166 scenarios. The upper
horizontal axis shows indexed gross world product (1990 = 1);
the lower axis indicates approximate absolute values by
multiplying the index by the 1990 value (US$20 trillion). For
reference, the gross world products of the IS92 scenarios are
indicated. The frequency distribution associated with scenarios
from the literature does not imply probability of occurrence.
•y-ir-Ov—I 'ThcOOO T'O Ol ОЧ ОЧ—' n W-l УЭ о
Range (lO'^USS)
Figure 2-6b: Histogram showing frequency distribution of
gross world product in 2100 for 148 scenarios. The upper
horizontal axis shows indexed gross world product (1990 = I);
the lower axis indicates approximate absolute values by
multiplying the index by the 1990 value (US$20 trillion). For
reference, the gross world products of the IS92 scenarios are
indicated. The frequency distribution associated with scenaiios
from the literature does not imply probability of occurrence.