Please note that the data and information posted under the "Open Process" are for historical information only. They were preliminary information released in 1998-1999 as part of the SRES open process and for use in analysis to be contained in the IPCC Third Assessment Report (TAR). For final data (version 1.1) please go back to home page and follow the link.

B2 Marker Scenario

Keywan Riahi and Alexander Roehrl

 

1. Storyline summary

Compared to the storylines for the other scenarios, especially A1 and B1, the B2 storyline describes a future that unfolds with more gradual changes and less extreme developments in all respects, including geopolitics, demographics, productivity growth, technological dynamics and other salient scenario characteristics. The more fragmented pattern of future development that is not all that different from the present precludes assuming any particularly strong convergence tendencies in the scenario quantification. The overall guiding principle for the choice of particular assumptions used in the scenario quantification was "dynamics as usual." Conversely, the strong emphasis on local and community values and solutions contained in the B2 storyline, were interpreted to represent successful management of local and regional problems associated with development. Consequently, the scenario quantification assumes effective policies in solving local and regional problems such as traffic congestion, local air pollution, and acid rain impacts.

 

2. Modeling Approach

The B2 marker scenario is a quantification of the B2 storyline (see B2 storyline and scenario family) using a set of integrated models developed at IIASA. The core model used for quantification of future GHG emissions is MESSAGE model (Model for Energy Supply Systems and their General Environmental Impact). This quantification of the marker scenario is the result of an iterative process that required repeated adjustments of input assumptions and model results to achieve the development paths of emissions and their main driving forces which are consistent with the storyline. This process was conducted in consultation with the writing team and other modeling groups. There are a number of other scenario variants developed with MESSAGE and other five models (AIM, IMAGE, ASF, MARIA, and MINICAM) of the B2 storyline constituting the B2 scenario family. The MESSAGE model was also used to quantify all four variants of the A1 storyline and scenario family and one variant of the B1 storyline and scenario family.

The IIASA model set covers energy sector and industrial emissions sources only. Agricultural and land-use related emissions for the B2 marker scenario were derived from a quantification of the B2 storyline by the AIM model. They are consistent with the energy-related emissions because they are based on assumptions about the main driving forces that are in line with those described below for the B2 quantification with MESSAGE model.

2.1 Introduction

This section gives a brief overview of B2 marker scenario and its main driving forces and other salient assumptions influencing future emissions. It presents a short description of the assumptions made for quantifying the B2 storyline and provides the information relevant for illustrating how this scenario was captured the MESSAGE model. Section 2.2 includes a description and tabular quantification of the main scenario driving forces, such as population and economic growth rates, energy demand, resource availability and technology assumptions. It also provides an overview of the interpretation of environmental policies and measures in the B2 marker scenario.

2.2 Scenario drivers

2.2.1 Population and economy

The B2 marker scenario is based on the central population projection, whereby global population increases to about 9.4 billion people by 2050 and to about 10.4 billion by 2100. Thus, the scenario describes a continuation of historical trends toward the completion of the global demographic transition in the next century. This is consistent with the more recent population projections that incorporate faster fertility decline in the world together with low mortality and thus project lower populations compared to the earlier studies. This demographic pattern appears to be captured the best by the UN median 1998 population projection, which has been adopted for the scenario quantification.

Table 1 gives the global and regional population in million people and the average annual percentage growth rates. This central (or median) population projection corresponds to a higher population increase than in A1 storyline and in B1 storyline, but is lower than that in A2 storyline storyline. The population growth is very small for the two regions that include the industrialized countries (OECD and REFs). In ASIA the population stabilizes, and in the rest of the world (ROW) the growth slows down toward the end of the century. This means that fertility declines in the developing countries, following the lead of the industrialized countries, approaches the replacement rates worldwide toward 2100. The fertility decline in the scenario is consistent with the relatively rapid economic growth and focus on regional development as foreseen in the B2 storyline.

Table 1: World population by region in million people and average annual growth rates in percent per year (in italics) between 1990 and 2100 (UN, 1998).

Region

1990

2020

2050

2100

1990-2100 %/yr

OECD

859

982

976

928

0.1

REFs

413

418

406

379

-0.1

ASIA

2798

4008

4696

4968

0.5

ROW

1192

2263

3289

4139

1.1

World

5262

7672

9367

10414

0.6

Table 2 illustrates global and regional economic development in the B2 marker scenario, measured by GDP (at 1990 prices and market exchange rates) and by average annual GDP growth rates. The world GDP increases by more than a factor of ten during the next century, from about US$21 trillion (thousand million) in the base year 1990 to about US$235 trillion by 2100. This development path, with the average world GDP growth rate of about 2.2 percent per year, corresponds to median levels of global economic development compared to other scenarios in the literature. For example, the world GDP by 2100 is close to the median value for the range of scenarios in the database. Consistent with historical experience, economic growth rates are higher in regions with lower labor productivity, i.e. regions with relatively low per capita GDP levels. However, economic growth rates in these regions decline over the long-term as labor productivity levels approach those of the leading countries. Thus, average GDP growth rates decline as the world develops. This means that the long-term GDP growth rates are lower in B2 marker scenario than the global average rate for the last hundred years and are generally more in line with the more recent experience in the industrialized countries.

 

Table 2: World GDP by region in trillion (thousand million) US dollars (at 1990 prices and exchange rates) and average annual growth in percent per year (in italics) between 1990 and 2100.

Region

1990

2020

2050

2100

1990-2100 %/yr

OECD

16.4

30.3

38.3

56.6

1.1

REFs

1.1

1.8

6.6

14.5

2.3

ASIA

1.5

13.2

41.8

97.1

3.8

ROW

1.9

5.5

22.8

66.8

3.2

World

20.9

50.7

109.5

234.9

2.2

The sustained pace of development and the stabilization of the world population at less than double the current level mean that the world generally achieves high levels of affluence. In accordance with the B2 storyline, the marker scenarios does not include any specific drivers or measures for achieving convergence between regions in par capita productivity or income. Table 3 shows the per capita GDP (at 1990 prices and market exchange rates) and average annual per capita GDP growth rates

Table 3: Income per capita in the world and by region in US dollars (at 1990 prices and exchange rates) and average annual growth in percent per year (in italics) between 1990 and 2100.

Region

1990

2020

2050

2100

1990-2100

%/yr

OECD

19092

30855

39242

60991

1.1

REFs

2663

4306

16256

38259

2.5

ASIA

536

3293

8901

19545

3.3

ROW

1594

2430

6932

16139

2.1

World

3972

6608

11690

22556

1.6

 

The large difference in per capita incomes between the rich and the poor persists in this scenario, but the gap narrows through the process of development. The average per capita GDP reaches about US$18,000 by 2100 in the developing countries, which exceeds the current levels in the OECD countries. In comparison, per capita GDP reaches about US$54,000 by 2100 in the developed regions, which corresponds to an income ratio of three-to-one between North and South, a considerable improvement in interregional equity by 2100. Average income per capita (Table 3) in the developing countries reaches US$18,000 in comparison to US$54,000 in the developed world, which corresponds to an income ratio of 3:1 between North and South in the year 2100. Nevertheless, per capita income differences among the world regions are higher than in A1 marker scenario and B1 marker scenario, but they are smaller than those in A2 marker scenario. An important factor contributing to this development, despite lower-than historical economic development rates, is the completion of the demographic transition in the B2 marker scenario. For instance, even today's most underdeveloped regions, such as Africa and South Asia, experience economic development to higher levels than in the A2 case in a large measure because of lower fertility rates.

2.2.2 Resource availability

The availability of fossil energy resources in the B2 marker scenario is consistent with the gradual change in line with the "dynamics as usual." This means that the dynamics of technological change in this scenario are comparable with the historical experience. Consequently, oil and gas resource availability expands only gradually while coal continues to be abundant. Oil and gas resources do not extend much beyond current conventional and unconventional reserves. Reserves are considered to be that part of the resources that can be extracted at current prices with current technologies. Through gradual improvements in technology a larger share of unconventional reserves and some resources are utilized during the next century.

Table 4: Fossil energy resources availability and cumulative consumption in B2 marker scenario in ZJ (1,000 EJ).

World Hydrocarbon Reserves and Resources in the B2 Marker Scenario, in ZJ

Conventional

Unconventional

Fuel

Identified Reserves and Resources a

Identified Reserves

Resources

Total

B2 Consumption

1990-2100

Oil

11.5

7.1

1.5 b

20.1

19.4

Gas

15.7

6.9

12.8 c

35.4

26.9

Coal

25.2

100.3 c

125.5

12.6

Cumulative Fossil Energy Consumption in the B2 Marker Scenario, 1990-2100, in ZJ

Gas

Oil

Coal

OECD

6.7

3.0

3.3

REFs

7.7

3.4

1.5

ASIA

4.0

1.7

6.7

ROW

8.5

11.3

1.1

World

26.9

19.4

12.6

a. Conventional resources: Masters et al., 1994 (Remaining to be discovered at a probability of 5%)

.b. 17% of total unconventional resources.

c. Currently recoverable unconventional resources (2.2 ZJ), and 60 % of unconventional resources that are recoverable with technological progress.

d. Unconventional resources that are currently recoverable or will be recoverable with technological progress.

Table 4 gives a summary of global fossil energy resources available in the B2 marker scenario and shows the cumulative regional fossil energy consumption in the scenario between 1990 and 2100. The availability of oil and gas is limited compared to the estimated magnitude of global fossil resources (IPCC, 1996). This translates into relatively limited energy options in general and extends to non-fossil energy options as well. Table 4 illustrates these limitations by showing that virtually all of the available conventional oil and about three-quarters of all gas resources are consumed by 2100.

 

2.2.3 Energy supply technologies

 

The dynamics of technological change in B2 marker scenario are comparable with the historical experience. This again can be interpreted as a typical characteristic of a median scenario. At the aggregate level this is indeed the case. Population, GDP and energy developments in the scenario are close to the median values of all scenarios in the SRES scenario database. Accordingly, the rates of technological change take intermediate rage when compared with the other three marker scenarios. This is also consistent with the B2 scenario storyline. At the same time, this interpretation is, at least to an extent, misleading. Technological innovation and diffusion are quite rapid at the regional level especially for the technologies with low adverse environmental impacts. A high level of regional cooperation, integration and environmental awareness characterizes B2 world. "Dynamics as usual" is the guiding principle and in the future, as in the past, regional rates of change can be quite rapid even though they usually translate into more modest aggregate global rates. At the regional level, the scenario departs quite drastically from the "median" appearance of its main driving forces at the global level.

Another important departure from this median characterization is the high level of environmental awareness at the regional level. In the B2 marker scenario this is reflected in faster development and diffusion of energy technologies with lower emissions of pollutants that cause local and regional adverse environmental impacts. This means that there is a steady and dedicated improvement of the current fossil technologies but less emphasis on radically new solutions that would require more drastic departures from the current technological development paths. For example, there are high cumulative improvements of clean gas technologies, such as advanced combined cycle systems, including the emergence of mini-turbines and fuel cells. At the same time, there are medium improvements of oil and renewable technologies. In the case of oil, it is due to higher adverse environmental impacts at the regional level, compared to gas. In the case of renewables, it is due to large development costs that are not shared globally. Coal technologies undergo the lowest aggregate rates of improvement and are subject to increasing environmental controls. There are increasing coal extraction costs in regions with a large share of deep underground coal mining due to labor costs. However, in regions with mainly surface coal mining (e.g., North America) coal extraction costs remain relatively low due to continuous automation.

2.2.4 Energy demand

Final energy demand was derived by applying end-use technologies to provide for the demand of electric and non-electric energy services, which in turn depend on the economic development rates, income levels and on the sectoral economic structure of each region. The evolution of the final energy demand levels and structure in the developing regions follow patterns that are similar to those of the historical developments in now industrialized regions of the world. This again is consistent with the "dynamics as usual" interpretation of the B2 storyline.

The result is energy intensity improvement rates at the global level that are in line with historical experience, at an average improvement rate of about one percent per year until 2100. Table 5 gives the final energy intensity for the world and the four regions and the average annual improvement rates in percent between 1990 and 2100. The average improvement rate disguises the fact that the improvement rates are relatively high initially, slowing down later, when the transition from a developing to industrial and post-industrial structure is complete in most of the world. The improvement rates are generally high in the developing regions and by no means represent median values. These high rates are related to rapid phases of economic growth take-off and development. In contrast, the improvement rates are humble even by historical standards in the highly developed economies. All told, the energy intensity decline is slower than in the A1 or B1 scenario families due to more moderate diffusion of new technologies and capital turnover rates. However, it is higher than in A2 with its more modest levels of economic growth. Despite the rapid economic development and energy intensity improvement in the developing regions of the world, the B2 marker scenario does not lead to a convergence in energy intensity levels across regions although the gap narrows substantially. This too is consistent with its characterization as "dynamics as usual," but the rapid rates of economic development and energy intensity improvement in the developing regions take this marker scenario clearly outside the "median" envelope.

Table 5: Final energy intensity world and regions in MJ per US dollar (at 1990 prices and exchange rates) and average annual improvement rate in percent per year (in italics) between 1990 and 2100.

Region

1990

2020

2050

2100

1990-2100

in %/yr

OECD

7.5

5.3

3.2

-0.8

REFs

45.8

27.1

10.3

5.4

-1.9

ASIA

41.0

10.9

6.0

4.0

-2.1

ROW

20.7

13.5

6.7

4.6

-1.4

World

12.9

8.5

6.0

4.0

-1.0

 

 

2.2.5 Environmental policies and measures

The B2 storyline foresees a high degree of regional environmental awareness and stewardship without any explicit assumptions about measures directed at mitigating climate change or other "global" change issues. The focus is on local and regional environmental protection. This scenario characteristic is also consistent with the notion of "dynamics as usual" as so vividly illustrated by the so-called environmental Kuznets curves. Essentially they show that the type and extent of pollution are closely related to the degree of economic development and industrialization. During the initial phases of development, air pollution from industrialization joins the traditional indoor air pollution as a major treat to human health and wellbeing. As development continues it enables societies to successfully address environmental problems of both poverty, such as inadequate sanitation or indoor air pollution from traditional biomass use, and industrialization, such as sulfur emissions. These environmental problems and challenges can be generally resolved as development progresses. There is little evidence to date that there are analogous Kuznets curves for global warming, namely that a similar effect might take place for reduction of greenhouse gas emissions at higher levels of general affluence than experienced to date.

The regional environmental protection character of the B2 storyline, together with the regional environmental stewardship as a consequence of successful development, lead to significant reductions of sulfur dioxide emissions. This is also in line with the "dynamics as usual" interpretation of this storyline, as it represents the continuation of current developments in the industrialized countries throughout the rest of the world when comparable standards of living are achieved. It is a kind of "graduation" clause that triggers sulfur control at higher levels of economic development through a shift away from sulfur-rich fuels, through desulfuriztion and through a shift to energy conversion processes that involve sulfur removal (e.g. synfuel production). Global sulfur emissions decline to less than 12 MtS by 2100, corresponding to about one-fifth of the 1990 emissions levels. This is well below the median value of all scenarios in the SRES scenario database, but is representative of scenarios from the literature with sulfur emissions controls as practiced today in Europe and the United States.

Carbon dioxide and other greenhouse gas emissions represent typical median values for all scenarios in the SRES scenario database. However, they are in the lower range of scenarios that do not foresee any explicit measures or policies to reduce greenhouse gas emissions. Dynamic structural changes in the scenario lead to a substantial degree of energy system decarbonization primarily through a shift from carbon-rich to carbon-poor energy sources. This shift is triggered by the combination of a number of scenario driving forces without any explicit assumptions about greenhouse gas emissions policies. They are absent in the B2 marker scenario. Nevertheless, global carbon dioxide emissions more than double to about 6 GtC in 1990 to some 14 GtC by 2100.

The combined effects of lower sulfur and higher carbon dioxide emissions leads to an average annual increase in radiative forcing of about one percent per year. This increase corresponds to additional forcing of about 4.2 W/m2 by 2100 compared to 1990. This radiative forcing is characteristic of scenarios with higher rates of greenhouse gas emissions in combination with higher sulfur and other aerosol emissions. The relatively high radiative forcing in B2 marker scenario is due to both the higher greenhouse gas concentrations and to the "loss" of sulfates regional cooling effect. These environmental characteristics of the B2 marker scenario are outside the "median" envelope, even though they emerge with typically median values of the main emissions driving forces, such as population growth, economic development and energy consumption.