Emissions Scenarios - IPCC

An Overview of Scenarios 231
Table 4-19: Date (rounded to nearest 5 years) wiien DEV countries reach 1990 levels of IND countries (top panel), and date
when they reach parity (and overtake) projected IND country levels (bottom panel). Dates are given for the four SRES marker
scenarios.
Reaching 1990 IND levels A2 B2 AlB Bl
GDP (тех) -2030 -2020 -2015 -2020
GDP (PPP) (IIASA runs) -2010 - 2005 -2000 -2000
GDP (тех) per capita >2100 - 2080 -2050 -2060
Primary energy -2010 -2010 -2005 -2005
Primary energy per capita - - -2070 -
Annual COj - 2000 >2000 -2000 -2005
Cumulative CO^ since 1800 -2020 -2030 -2015 -2020
COT per capita - - - -
Overtaking IND A2 B2 AlB Bl
GDP (тех) -2060 -2035 -2030 -2035
GDP (ppp) (IIASA runs) - 2030 - 2020 -2015 -2010
GDP (тех) per capita - - - —
Primary energy -2015 -2020 -2010 -2005
Primary energy per capita - - >2100 _
Annual CO2 -2000 -2005 -2000 -2005
Cumulative CO^ since 1800 -2050 -2110 -2040 -2050
CO2 per capita - - - -
тех.
marlcet exchange rate; ppp, purchasing power parities.
- Denotes that no date can be given within the time horizon of the SRES scenarios (to 2100) or short-term trend extrapolations after that date.
2060. Total primary energy use in developing countries could
reach 1990 industrial levels between 2005 and 2010, and parity
in absolute terms between 2005 and 2020. Possible spatial
distributions of economic activities based on satellite night
imagery data that coiTelate highly with, for example, GDP and
electricity use are discussed in Box 4-10.
Conversely, scenario per capita indicators converge only
slowly, sometimes well after 2100. Per capita GDP (expressed
at market exchange rates) of developing countries reaches the
1990 level of industrial countries at the earliest around 2050
(scenario family Al) and well after 2100 in scenario family A2.
None of the four marker scenarios projects a situation in which
per capita income in developing countries surpasses future
levels of per capita incomes of Annex I countries. Energy use
per capita shows a similar pattern. Only scenario family Al
depicts a development in which per capita energy use in
developing countries could approach that prevailing in
industrial countries in 1990 (by 2070) and in which it could
reach parity with industrial countries in the very long-term
(after 2100). In all other scenarios energy use per capita
remains below 1990 or future per capita energy use levels of
industrial countries. By and large, these scenario features
reflect the very large differences in present per capita levels of
economic activity and energy use, which require many
decades, even a century, to narrow. The scenarios thus portray
a feature Jmown as '"slow conditional convergence only" in the
development literature (see, e.g.. Shin, 1996).
Conceming GHG emissions, discussed in more detail in
Chapter 5, trends reflect the evolution of scenario-driving
forces discussed above. CO2 emissions of developing countries
reach levels in industrial countries around or shortiy after the
year 2000. This reflects the continued growth in energy use
(and emissions), slow recovery of economies in transition (and
thus modest growth in aggregate emission from industrial
countries), and a continuation of current trends in land-use
changes (deforestation); these only diverge in the medium- to
long-tenn across the SRES scenarios.
Yet, even with equalizing total emission levels, regional
differences in cumulative and per capita emissions remain
pronounced. Based on the estimates of cumulative CO^ (all
sources) emissions since 1800 given in Grübler and
Nakicenovic (1994), developing countries reach 1990 levels of
industrial countries only between 2015 and 2030. They reach
parity (historical data from 1800 to 1990, and scenario values
from 1990 onward) at earliest by 2040 (scenario family Al),
and between 2050 (A2 and Bl) and post-2100 (scenario family
B2) in the other scenarios. None of the SRES scenarios reaches
the 1990 per capita CO2 emissions levels of industrial countries
in the developing countries.
In scenarios with vigorous climate policies (not in the SRES
terms of reference) per capita emissions levels in industrial
countries may approach levels as projected for developing
countries. However, no scenario without climate policies could