IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group III: Mitigation of Climate Change The baseline

All mitigation potentials have to be estimated against a baseline. The main baseline scenarios used for compiling the assessments in the chapters are the SRES B2 and A1B marker scenarios (IPCC, 2000) and the World Energy Outlook 2004 (WEO2004) (IEA, 2004). The assumed emissions in the three baseline scenarios vary in magnitude and regional distribution. The baseline scenarios B2 and WEO2004 are comparable in the main assumptions for population, GDP and energy use. Figure 11.1 shows that the emissions are also comparable. Scenario A1B, which assumes relatively higher economic growth, shows substantially higher emissions in countries outside the OECD/EIT region.

Figure 11.1

Figure 11.1: Energy-related CO2-only emissions per world region for the year 2030 in the World Energy Outlook, and in the SRES B2 and A1B scenarios

Source: Price et al., 2006.

The crude oil prices assumed in SRES B2 and WEO2004 are of the same order of magnitude. The oil prices in the SRES scenarios vary across studies. For the MESSAGE model (B2 scenario), the price is about 25 US$/barrel (Riahi et al., 2006). In the case of the WEO2004, for example, the oil price assumed in 2030 is 29 US$/barrel. These prices (and all other energy price assumptions) are substantially lower than those prevailing in 2006 and assumed for later projections (IEA, 2005 and 2006b). The 2002–6 rises in world energy prices are also reflected in the energy futures markets for at least another five to ten years. In fact, the rise in crude oil prices during this period, some 50 US$/barrel, is comparable to the impact of a 100 US$/tCO2-eq increase in the price of carbon. However, it is still uncertain whether these price increases will have a significant impact on the long-term energy price trend.

Higher energy prices and further action on mitigation may reinforce each other in their impact on mitigation potential, although it is still uncertain how and to what extent. On the one hand, for instance, economies of scale may facilitate the introduction of some new technologies if supported by a higher energy price trend. On the other hand, it is also conceivable that, once some cost-effective innovation has already been triggered by higher energy prices, any further mitigation action through policies and measures may become more costly and difficult. Finally, although general energy prices rises will encourage energy efficiency, the mix of the different fuel prices is also important. Oil and gas prices have risen substantially in relation to coal prices 2002–6, and this will encourage greater use of coal, for example in electricity generation, increasing GHG emissions.

As a rule, the SRES B2 and WEO2004 baselines were both used for the synthesis of the emission mitigation potentials by sector. Most chapters have reported the mitigation potential for at least one of these baseline scenarios. There are a few exceptions. Chapter 5 (transportation) uses a different, more suitable, scenario (WBCSD, 2004). However, it is comparable to WEO2004. Chapter 6 (buildings) constructed a baseline scenario with CO2 emissions between those of the SRES B2 and A1B marker scenarios taken from the literature (see Section 6.5). The agriculture and forestry sectors based their mitigation potential on changes in land use as deduced from various scenarios (including marker scenarios, see Sections 8.4.3 and 9.4.3). The SRES scenarios did not include enough detail for the waste sector, so Chapter 10 used the GDP and population figures from SRES A1B and the methodologies described in IPCC Guidelines 2006 (see Section 10.4.7).

Table 11.1 compares the emissions of the different sectoral baselines for 2004 and 2030 against a background of the end-use and point-of-emission allocation of emissions attributed to electricity use. Since the 2030 data are from studies that differ in terms of coverage and comparability, they should not be directly aggregated across the different sectors and therefore no totals across all sectors are shown in Table 11.16. An important difference between the WEO baseline and SRES B2 is that the WEO emissions do not include all non-CO2 GHG emissions.

Table 11.1: Overview of the global emissions for the year 2004 and the baseline emissions for all GHGs adopted for the year 2030 (in GtCO2-eq)

 Global emissions 2004 (allocated to the end-use sector)a, c Global emissions 2004 (point of emissions)a, b Type of baseline usedd Global emissions 2030 (allocated to the end-use sector) Global emissions 2030 (point of emissions) 
Energy supply - j 12.7 WEO - j, f) 15.8 f) 
Transport 6.4 6.4 WEO 10.6 f) 10.6 f) 
Buildings 9.2 3.9 Own 14.3 f)  5.9 e) f) 
Industry 12.0 9.5 B2/USEPA 14.6  8.5 g) 
Agriculture 6.6 6.6 B2/FAO 8.3 8.3 
LULUCF/Forestryk) 5.8 5.8 Own 5.8 h) 5.8 h) 
Wastei) 1.4 1.4 A1B 2.1 2.1 


a) The emissions in the year 2004 as reported in the sectoral chapters and Chapter 1, Figure 1.3a/b.

b) The allocation to point of emission means that the emissions are allocated to the sector where the emission takes place. For example, electricity emissions are allocated to the power sector. There is a difference between the sum when allocating the emissions in different ways. This is explained by the exclusion of electricity emissions from the agricultural and transport sectors due to lack of data and by the exclusion of emissions from conversion of energy as most end-use emissions are based on final energy supply.

c) ‘Allocated to the end-use sector’ means that the emissions are allocated to the sectors that use the energy. For example, electricity emissions are allocated to the end-use sectors, mainly buildings and industry. Emissions from extraction and distribution are not included here.

d) See text for further clarification on the type of baselines used.

e) This figure is based on the assumption that the share of electricity-related emissions in the constructed baseline in Chapter 6 is the same as for the SRES B2 scenario. According to Price et al. (2006), the electricity-related emissions amount to 59%. 59% of the baseline (14.3 GtCO2-eq) is 8.4 GtCO2-eq. The remaining emissions are allocated to the buildings sector.

f) 2030 emissions of the F-gases are not available for the Transport, Buildings, and Energy Supply sectors.

g) Source: Price et al., 2006.

h) No baseline emissions for the year 2030 from the forestry sector are reported. See 9.4.3. On the basis of top-down models, it can be expected that the emissions in 2030 will be similar to 2004.

i) The data for waste include waste disposal, wastewater and incineration. The emissions from wastewater treatment are for the years 2005 and 2020.

j) The emissions from conversion losses are not included due to lack of data.

k) Note that the peat fires and other bog fires, as mentioned in Chapter 1, are not included here. Nor are they included in Chapters 8 and 9.