5.4 Sector- and Technology-specific Barriers and Opportunities
GHG emissions from some sectors are larger than those from others, and the
importance of each GHG varies across sectors as well. Methane (CH4)
for instance is a much bigger contributor to emissions from agricultural activity
than, for instance, from the industry sector. Table 5.4
shows the carbon emissions from energy use in 1995. Emissions from electricity
generation are allocated to the respective consuming sector. Carbon emissions
from the industrial sector clearly constitute the largest share, while those
from agricultural energy use form the smallest share. In terms of growth rates
of carbon emissions, however, the fastest growing sectors are transport and
buildings. With rapid urbanization promoting increased use of fossil fuels for
habitation and mobility in many countries, the two sectors are likely to continue
to grow faster than others will in the future.
Annual carbon emissions from land-use change were estimated in the IPCC Special
Report on Land Use, Land-use Change and Forestry at 1.6 ±0.8GtC/yr for
the period 1989 to 1998 (IPCC, 2000a). Tropical forests are estimated to be
net emitters, but temperate and boreal forests are net sequesters of carbon.
CH4 emissions from livestock, rice paddies, biomass burning, and
natural wetlands add up to 1.8GtCeq/yr with considerable uncertainty about these
estimates. Below we describe the sector-specific barriers to and opportunities
for reducing the sectoral GHG emissions.
| Table 5.4: Carbon emissions from fossil fuel combustion
(MtC) |
 |
| Sector |
Carbon emissions and % share1
1995
|
Average annual growth rate (%)
|
|
1971 to 1990
|
1990 to 1995
|
|
| Industry Buildings |
2370 (43%)
|
1.7
|
0.4
|
| --Residential |
1172 (21%)
|
1.8
|
1.0
|
| --Commercial |
584 (10%)
|
2.2
|
1.0
|
| Transport |
1227 (22%)
|
2.6
|
2.4
|
| Agriculture |
223 (4%)
|
3.8
|
0.8
|
| All sectors |
5577 (100%)
|
2.0
|
1.0
|
| --Electricity generation2 |
1762 (32%)
|
2.3
|
1.7
|
|
