1、 外文翻译 原文 Energy Content of World Trade Material Source: Energy Policy Author: Gernot Wagner ENERGY CONTENT OF WORLD TRADE Gernot Wagner* Environmental Defense Fund 257 Park Avenue South, New York, NY 10023; +1-212-616-1341 gwagnerpost.harvard.edu This paper constructs a comprehensive dataset of oil
2、and total energy embedded in world trade of manufacturing goods for 73 countries from 1978 to 2000. Applying the data to debates on the dependency on foreign energy sources makes clear that achieving complete energy independence in the foreseeable future is unlikely to be feasible and may not be des
3、irable. Applying it to the discussion of environmental Kuznets curves (EKCs) highlights an important distinction between production and consumption of energy. Richer countries use relatively less energy in their industrial production yet still consume relatively large amounts of energy indirectly. A
4、 further investigation largely excludes structural shifts of production in and out of the manufacturing sector as an explanation for the downward-sloping portion of the EKC. Country-level analyses addcaveats but show tentative support for the cross-country conclusions. Keywords: trade, energy depend
5、ency, energy intensity, environmental Kuznets curve, energy Kuznets curve 1. Introduction The United States imports around 10 million barrels of oil per day.i This number is widely known. It is also of much concern in the policy community. “Energy independence” has been buzzword in Washington since
6、the 1970s. The Council on Foreign Relations (CFR) Independent Task Force Report on the “National Security Consequences of U.S. Oil Dependency” identified it as one of the main myths. In the foreseeable future, the United States will depend on imported oil, “barring draconian measures” (CFR 2007) tha
7、t, in any case, would be ill advised. More importantly, even if the United States becomes “energy independent” in the sense conveyed in the report and in much of the policy discussion, it would still depend on imported oil through its trade in manufacturing goods. In 2000, the United States imported
8、 0.8 million barrels of oil per day embedded in imported manufacturing goods. The number increases to 2.4 million barrels of oil-equivalent energy when accounting for all energy sources (compared to 13.2 million barrels of oilequivalent energy imported directly. These embedded energy numbers are not
9、 officially calculated and do not register in the policy discussion on energy dependency. Part 2 of this paper focuses on this dataset, which accounts for how much oil and energy are embedded in world trade and lays out possible policy implications. Using detailed data on the energy content of world
10、 trade and given a high correlation between energy use and CO2-emissions, we can reexamine a well-known and much-discussed relationship between growth and the environment in part 3. The environmental Kuznets curve (EKC) postulates an inverse-U relationship between pollution and per-capita income. At
11、 low levels of development, pollution increases with income at an ever-decreasing rate until the relationship reverses at high levels of development. Pollution now decreases with income. (Figure 1) Described in theory and supported by anecdotal evidence, broad cross-country empirical studies provide
12、 a mixed picture. Figure 1 Common theoretical explanation of observed environmental Kuznets curve (EKC) patterns. Grossman and Krueger (1995) and Selden and Song (1994) were the first to find crosscountry EKCs, but subsequent studies have cast doubts on the general conclusions. Harbaugh, Levinson an
13、d Wilson (2002) reexamine the evidence and find that the results are highly sensitive to covariates and sample size and ultimately conclude, “that there is little empirical supported for an inverted U-shaped relationship between several important air pollutants and national income.” Dijkgraaf and Vo
14、llebergh (2005) also challenge the existence of an EKC for CO2 emissions, which had previously been shown by Schmalensee, Stoker and Judson (1998). Cole (2003) provides a notable recent exception. He finds support for robust cross-country EKCs for several common pollutants. Brock and Taylor (2004) p
15、rovide a well-grounded theoretical explanation for the EKC and successfully test the predicted convergence in pollution across OECD countries. Panayotou (2000) and Smulders (2000) offer surveys of the theoretical explanations driving the EKC Others have looked directly at the energy-income relations
16、hip, which ought to be similar to patterns observed for CO2 (Galli 1999, Suri and Chapman 1998, Medlock and Soligo 2001, Judson, Schmalensee and Stoker 1999, Richmond and Kaufmann 2006). Trade complicates the basic EKC-story. It enables countries to produce in different sectors than they consume. Su
17、ri and Chapman (1998), for example, find that richer countries are increasingly importing more energy-intensive products. Including trade also enables a separation of production and consumption EKCs. Potentially harmful effects from energy-intensive goods accrue at the point of production. Consuming
18、 these goods releases no further significant quantities of pollution (Figure 2). We may, therefore, expect to find EKCs for production of energy, but perhaps none for consumption. Figure 2 Trade allows a discrepancy between environmental Kuznets curve (EKC) associated with consumption and the actual
19、 environmental impact from production. We will differentiate between production and consumption EKCs in section 3. Following Aldy (2005, 2007), who focuses on CO2-emissions in the United States and inter-state electricity trade, we calculate consumption of oil and total energy in manufacturing using
20、 net factor trades combined with readily available production figures. Subsequently, we will focus on structural shifts in and out of the manufacturing sector and largely exclude them as potential drivers of the EKC. Lastly, we will analyze the EKC more closely using country-level time series econom
21、etric techniques. But first, a closer look at the dataset of factor trades in oil and energy. 2. Direct and embedded energy imports The market for oil and energy in general is globally integrated along two dimensions. Two-thirds of the worlds oil extracted each day crosses an international border be
22、fore it is consumed as a primary energy source. Supplies of oil are concentrated in relatively few countries. Five countries hold more than 60 percent of the worlds proven oil reserves; the top twenty hold 95 percent.v This enormous supply concentration is the root of most national security concerns
23、 in the context of energy markets. Second, oil crosses borders embedded in manufacturing goods. In 2000,global trade in manufacturing goods accounted for 2.9 million barrels of oil per day, compared to 33.2 million barrels of oil per day traded directly. This calculation of oil used in industry incl
24、udes oil used as a direct input in manufacturing processes. It does not account for indirect oil used, for example by labor. Table I lists oil and energy import figures for the United States. The table includes direct imports and contrasts them with oil and energy embedded in manufacturing imports.
25、It also presents net import figures. The United States is a large net importer, yet some oil and other energy is also re-exported. This holds particularly true for oil and energy embedded in exports. On net, the United States imports 0.4 million barrels of oil embedded in trade per day, while the to
26、tal figure for embedded imports amounts to 0.8 million barrels in 2000. This last figure is the salient number for energy security considerations, where the entire dependence on foreign oil is more relevant than “net dependence,” imports minus exports. Table I Oil and total energy imports into the U
27、nited States (million barrels of oil and oilequivalent per day). Appendix A describes the data sources. We employ oil, coal and gas consumption data for industry and the total economy as well as their exports and imports and make two assumptions about crude oil use. First, we assume that the ratio o
28、f crude use to total energy use in manufacturing for country c and time t, oil /ect , is the same as in the overall economy, indicated by T for total, oilT /eTct. This assumption enables us to calculate total oil use in the manufacturing sector: subsequently presented in units of barrels per capita
29、per day and referred to as , used in parallel with . For later use, we can split up and into intensities per unit of manufacturing output and manufacturing output, yct , in million 2000 US dollars: where yct figures come directly from UNIDOs Industrial Statistics Database aggregated across industria
30、l sectors. It is unclear which bias this assumption introduces, if any. While it is true that instead of using crude oil directly, industry often relies on other oil products derived from crude, total (direct and indirect) crude use would likely be influenced much less. Second, we assume that export
31、ing industry sectors are as energy intensive as sectors catering to the domestic market. This assumption allows us to calculate the aggregate amount of oil and overall energy embedded in manufacturing imports, M, and exports, X, from and to all other countries d: Poorer countries are more energy int
32、ensive than richer ones. But we may expect exporting sectors in poorer countries to employ production technologies that are more advanced than sectors catering to the domestic market and may, therefore, be more energy efficient. In that case, this assumption may lead to overestimates of the energy c
33、ontent of trade. On the other hand, the pollution haven hypothesis suggests that poorer countries may export particularly energy and pollution-intensive products. Kellogg (2007) confirms this conjecture for coal. If this is the overwhelming effect, the assumption may underestimate the energy content
34、 of trade. However, Kellogg also finds that the absolute magnitude of the effect is small.vi This is in line with the observation that energy markets are relatively global compared to markets for labor. We would expect that most trade be driven by wage differentials rather than competition based on
35、energy-intensity. In particular, a country like China is not directly competing with the United States for manufacturing jobs. Rather, it is competing with Mexico, Malaysia and other lowerwage producers, which employ similarly high-energy intensive technologies. If this effect dominates, this assump
36、tion is unlikely to introduce any significant bias. Lastly, we calculate oil and energy use in consumption of manufactured goods by subtracting net manufacturing exports from production figures: Throughout the paper, we frequently refer to both oilcti and ecti by the abbreviation Ecti , where i cons
37、, prod, and normalize all quantities to units of barrels of oil per capita per day. The complete dataset for all 73 countries in the sample spanning the years 1978 through 2000 is available on http:/ Others have worked on similar energy trade datasets, most notably Hertwich and Peters (2009), which
38、focuses on cross-national and cross-sectional data. Wyckoff and Roop (1994) calculate the energy content of imports using a methodology analogous to this analysis, with the goal of imputing carbon contents and the possibility for emissions leakage in a Kyoto-style climate change agreement. Their ana
39、lysis focuses on one year between 1984 and 1986 for each of six countries: Canada, France, Germany, Japan, the United Kingdom and the United States. See also Machado, Schaeffer and Worrell (2001), who calculate the energy content of trade for Brazil in 1995, and Kellogg (2007), who calculates detail
40、ed factor trades in coal for 64 sectors in 17 countries for the years 1985-1997. Direct and indirect dependency on foreign energy sources The extent of the present dataset and the inclusion of both direct and embedded energy flows ought to enable a better-informed energy security debate. For one, th
41、e focus on embedded energy content highlights the misconception that energy independence is possible or even desirable. Short of cutting off all world trade, the United States will always depend on foreign energy sources through its imports of manufacturing goods, even if it were possible to limit d
42、irect energy imports. Other more intricate implications focus on political realignments of U.S. trading partners and potential leverage of the United States, given its overall trade relationships. CFC (2007) highlights Chinese bilateral oil deals as an illustration of political interventions in oil
43、markets. The present data allow us to quantify the energy link between the United States and China in more detail. In 2000, the United States imported 800 thousand barrels of oil per day embedded in imports of manufacturing goods (Table I). Of those, 100 thousand came from China (Table II). Similarl
44、y, 0.6 of 2.4 million of oil-equivalent barrels of energy embedded in U.S. imports per day came from China. Table II presents these numbers for the years 1978 to 2000, with a clearly visible positive time trend primarily driven by increased overall imports of manufacturing goods from China to the Un
45、ited States. Table II Oil and energy imports from China to the United States (million barrels of oil and oilequivalent per day) and oil and energy import intensities for imports from China and all imports (barrels of oil and oil-equivalent per million dollars of imports in 2000 dollars). The table h
46、ighlights another stark fact concerning energy intensities. U.S. imports from China in 2000 contained 433 barrels of oil per million dollars of imports. This was more than 50 percent above the average of 279 for all U.S. imports. The difference for all energy sources was even larger. U.S. imports fr
47、om China in 2000 contained 2,308 barrels of oil-equivalent energy per million dollars of imports, more than 2.5 times the average import-intensity of 851 barrels per million dollars. One immediate implication of this discrepancy in energy intensities is that some of the U.S. dependency on foreign oi
48、l and energy embodied in world trade may be reduced at the source through measures of increasing energy efficiency. The next section will take a closer look at other implications arising from different energy intensities across countries. 3. Energy, growth, and trade The extent of the present datase
49、t allows a reexamination of the energy and income relationship. Environmental Kuznets Curve (EKC) analyses commonly argue that aggregate pollution first increases with rising per capita income and then falls, tracing out an inverse Urelationship. Following Selden and Song (1994), Cole (2000) and Richmond and Kaufmann (2006) among others, this present analysis focuses on per capita figures. This disentangles the effects of energy use per capita and population growth. The EKC story, however, is still the same. Poor
