4.5. Regional Scenario Patterns
The scenarios imply different regional patterns of socio-economic driving forces
and resultant emissions. These are summarized in Table 4-19.
Following the definition of the four world regions adopted in this report,
the industrial region (IND) corresponds to the SRES regions OECD90 and REF,
and the developing region (DEV) corresponds to the SRES regions ASIA and ALM.
In 1990, the base year of the SRES scenarios, driving-force variables as well
as emissions are distributed unevenly. According to the statistics reported
in Nakic´enovic´ et al. (1998), DEV countries account for 76% of global population.
However, they only account for 16% to 36% of global economic activity (considering
GDP at market exchange rates and purchasing power parities, respectively), 34%
of primary energy use, and 42% of global CO2 emissions (including all sources,
from energy plus land-use changes).
Over time, the regional distribution of socio-economic activities and emission
shifts in the scenarios, albeit because of different driving forces. These shifts
range from rapid population growth (scenario family A2) and rapid economic development
and catch-up (scenario family A1) in developing countries, to rapid "dematerialization"
of economic activities in industrial countries (scenario family B1). Generally,
scenario family B2 depicts the most gradual changes, and hence also the slowest
rates of change in the global distribution of activities and emissions. Of all
the SRES scenarios, A2-A1-MiniCAM exhibits the slowest dynamics of development
catch-up.
Table 4-19 summarizes the main scenario indicators differentiated between industrial
and developing countries. Two measures are given (following La Rovere, 1998):
- Date when activities and/or emissions in developing countries reach those
that prevailed in industrial countries in 1990.
- Date when developing country values equalize those of industrial countries.
In this comparison, developing countries in 1990 already accounted for 76%
of world population and, because of the inevitable demographic momentum, their
share is likely to increase further over the next few decades before alternative
demographic projections branch out into different regional distributions. However,
the basic pattern of dominance of developing countries in global population
remains unchanged across all demographic projections. The share of developing
countries in global population ranges between 80% (A1, B1) and 86% (A2, B2)
by 2100 for demographic projections between 7 and 15 billion people. From the
distribution of global population, the scenarios indicate an increasing importance
of developing countries in the future, albeit at different rates.
Table 4-19: Date (rounded to nearest 5 years) when
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
|
A1B
|
B1
|
|
GDP (mex) |
~ 2030
|
~2020
|
~2015
|
~2020
|
GDP (ppp) (IIASA runs) |
~ 2010
|
~2005
|
~2000
|
~2000
|
GDP (mex) per capita |
>2100
|
~2080
|
~2050
|
~2060
|
Primary energy |
~2010
|
~2010
|
~2005
|
~2005
|
Primary energy per capita |
-
|
-
|
~2070
|
-
|
Annual CO2 |
~2000
|
>2000
|
~2000
|
~2005
|
Cumulative CO2 since 1800 |
~2020
|
~2030
|
~2015
|
~2020
|
CO2 per capita |
-
|
-
|
-
|
-
|
Overtaking IND |
A2
|
B2
|
A1B
|
B1
|
|
GDP (mex) |
~2060
|
~2035
|
~2030
|
~2035
|
GDP (ppp) (IIASA runs) |
~2030
|
~2020
|
~2015
|
~2010
|
GDP (mex) per capita |
-
|
-
|
-
|
-
|
Primary energy |
~2015
|
~2020
|
~2010
|
~2005
|
Primary energy per capita |
-
|
-
|
>2100
|
-
|
Annual CO2 |
~2000
|
~2005
|
~2000
|
~2005
|
Cumulative CO2 since 1800 |
~2050
|
~2110
|
~2040
|
~2050
|
CO2 per capita |
-
|
-
|
-
|
-
|
|
mex, market 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. |
In consequence, as shown in Table 4-19, total GDP expressed at purchasing power
parities in developing countries could reach 1990 levels in industrial regions
between 2000 and 2010 and equalize future industrial country levels between
2010 and 2030. For GDP expressed at market exchange rates, the 1990 "parity
date" is reached between 2015 and 2030 and equalization in absolute terms even
later, between 2030 and 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 correlate 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 A1) 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
A1 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 known as "slow conditional
convergence only" in the development literature (see, e.g., Shin, 1996).
Concerning 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 shortly
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-term
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
CO2 (all sources) emissions since 1800 given in Grübler and Nakic´enovic´ (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 A1), and between
2050 (A2 and B1) 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
be found in the literature in which per capita emissions in industrialized and
developing countries reached similar levels. Thus the absence of such convergence
in the SRES scenarios reflects the current literature, and results from the
nature of the SRES scenarios as "no climate policy" scenarios.
SRES scenarios do follow the recommendation to explore possible pathways of
closing the income gap between the industrial and now developing regions (Alcamo
et al., 1995). For reasons of plausibility and foundation in the reviewed no-climate-
policy literature, the SRES scenarios do not achieve full income convergence
in the scenario period analyzed. However, income levels in developing countries
do reach the 1990 levels of the industrial countries in the second half of the
next century in three out of four scenario families.
|