Extended discussion here
Carbon emissions per capita 1973 vs. 1991 by major end use. (Denmark comparison is 1972 and 1991)
With the third Conference of the Parties (COP-3) in Kyoto approaching, there is a great deal of excitement over policies designed to reduce future carbon dioxide (CO2) emissions from fossil fuels. At COP-3, more than 130 nations will meet to create legally binding targets for CO2 reductions. Accordingly, we have analyzed the patterns of emissions arising from the end uses of energy (and electricity production) in ten industrialized countries, with surprising and, in some cases, worrisome results. The surprise is that emissions in many countries in the early 1990s were lower than in the 1970s in an absolute sense and on a per capita basis; the worry is that factors that reduced emissions in the past are not having the same effect in the mid-1990s.
We traced the evolution of economic output and human activities from 1970 to 1993 and analyzed emissions from nearly three dozen energy uses or economic subsectors. The figure shows our first-stage results, CO2 emissions by end-use sector or subsector for ten countries in 1973 and 1991, normalized to each country's population. In these calculations, electricity is reported at the annual average rate of CO2 emissions per unit of electricity delivered to the economy (excluding exports or imports).
The lesson of the figure is that emissions per capita fell in most countries we studied. Even in absolute terms, emissions from the major energy end uses and associated power and heat production fell in most countries. In general, manufacturing showed the most consistent decline relative to activity, with emissions/output (carbon intensity) falling between 25 percent (Denmark) and 67 percent (Sweden). Lower energy intensities were the main reason, but shifts away from solid fuels and oil also aided this decline. Emissions per capita from the residential sector fell in all but two countries, while emissions from services generally declined relative to output, depending on how much space heating intensity fell and how much CO2 was released in producing electricity.
The personal transportation sector behaved differently. Emissions from travel fell only in the U.S. and Canada, a result of the great decline in fuel use/km for cars. In Japan and Europe, there was increased motorization, modest declines in fuel use/km, and, in most countries, an increase in fuel use per passenger-km. The sum of these factors pushed per capita emissions up.
In all, falling energy intensities and changes in final fuel and utility fuel mix led to lower releases of carbon, while structural changes within sectors and increases in activity raised emissions. But the rate of decline in sectoral energy intensities has slowed in the 1990s; indeed, in the U.S. automobile fuel use/km has stopped falling and even rose slightly after 1991. This means that a key component that restrained or even reduced emissions weakened through the early 1990s.
The analysis also shows where per capita emissions differ from country to country. The most important differentiating factor is gross domestic product (GDP) per capita, followed by structural differences, energy intensity, and fuel mix (including utility fuel mix). The U.S. has a slightly higher-than-average ratio of CO2 emissions to primary energy consumed; somewhat higher-than-average energy intensities in travel, services, and manufacturing; and above all, larger homes and more driving per capita, which account for higher emissions there.
These findings raise important issues for the Kyoto meeting. Should countries with higher-than-average GDP growth rates be expected to cut their emissions/GDP more than those with lower growth? Do past reductions in emissions that cannot be repeated easily (such as big reductions in fossil fuel use for electricity generation or very great cuts in the energy intensity of space heating) be taken into account in the discussion of future restraint or reductions? Should differences in emissions that arise because of climate, house size, or geography be subject to negotiation?
Reducing energy intensities by improving energy efficiencies is crucial to further emissions cuts. Now that most of the energy-efficiency programs of the 1980s have run their course and real energy prices are for the most part stable or falling, it is no surprise that the rate of intensity reduction has fallen. Just what combination of taxation, efficiency programs, and new technology will spark significant restraint or reductions in the face of continued economic growth continues to vex experts.
Extended discussion here
—Lee Schipper and Mike Ting
Energy Analysis Program
(510) 486-5916; (510) 486-6996 fax
This work is supported by the DOE's, Office of Building Technologies, State and Community Programs; and the Environmental Protection Agency, Climate Change Branch.