Net Greenhouse Gas Emissions for Magazine and Dimensional Lumber Products

Transcription

1 Net Greenhouse Gas Emissions for Magazine and Dimensional Lumber Products Stith T. Gower 1, Ann Mckeon-Ruediger 2, Ann Reitter 2, Michael J. Bradley 3, Amy Taup 4, Timothy Tollefson 5, A.Fred Souba Jr. 5, J. David Reifkin 4, Barbara L. Embury-Williams 3, Steve Schiavone 4, James D. Weinbauer 6, Anthony C. Janetos 7, Karen Johnston 8 1 Department of Forest Ecology & Management, University of Wisconsin, Madison, WI 53706, USA 2 StoraEnso North America, Division of Air Programs, Wisconsin Rapids, WI Canfor, Division of Technology, Vancouver, British Columbia, Canada V6C 2C1 4 TI Paperco Inc., Time and Life Building, New York, NY StoraEnso North America, Division of Forest Resources, Wisconsin Rapids, WI StoraEnso North America, Division of Environmental Affairs, Wisconsin Rapids, WI The H. John Heinz III Center for Science, Economics, and the Environment, Washington, D.C The Home Depot, Atlanta, GA

2 Greenhouse gases (GHG) are important by-products of the production of wood and paper products. Here we report the GHG life cycle analysis (LCA) for three forest product chains: a weekly (TIME) and monthly (InStyle) magazine, and dimensional lumber. In this study we show (i) one ton of TIME or InStyle magazines releases a net 1.17 and 1.11 t CO 2 eq, respectively, with GHG emissions from the pulp and paper mills comprising 61-77% of total GHG emissions, and (ii) one ton of dimensional lumber releases a net 0.83 t CO 2 -eq, with transportation and distribution from the sawmill to consumer comprising 94% of the total GHG emissions. CO 2 comprised greater than 99% of the total CO 2 -eq (CO2 + CH 4 + N 2 O) emissions for both product chains. We identify opportunities to reduce GHG shadows for the magazine and dimensional lumber chains and emphasize the important role of the industrial forest C cycle in forest C management. The rising concentration of greenhouse gases (GHG) in the atmosphere is now recognized as a primary cause for climate change 1. The forest carbon cycle is comprised of two inter-linked cycles: the biological and industrial cycle 2. Forests are an important source for fiber and fuel for humans, and the forest vegetation contains almost 90% of the total terrestrial vegetation carbon 3. Much research effort has focused on quantifying the effects of global change on the biological carbon cycle of forests, specifically the exchange of carbon dioxide (CO 2 ) and other greenhouse gases (GHG) between forests and the atmosphere 4-7. The industrial carbon cycle of forests is less well studied, but GHG emissions from the industrial carbon cycle of forests are significant. Humans consume approximately 270 x 10 6 tons of paper annually worldwide, and the pulp and paper industry consumes the fifth largest amount of energy of any industry in the world 8. Wood products contain significant quantities of carbon, leading some scientists to conclude that they are carbon sinks However, many analyses of carbon storage in 2

3 forest products have not included GHG emissions from the production, transportation, utilization, or final fate of the forest products. Life-cycle analysis (LCA) is a tool in industrial ecology that is used to evaluate the environmental burdens of a product or process by quantifying the energy and materials used to manufacture the product and the waste(s) produced 12. Omitting important GHG emissions of a forest product cause erroneous conclusions about net C storage in forest products and misguide forest managers and policy makers trying to identify and implement opportunities to reduce GHG emissions. In this study we conduct a LCA of the net GHG (CO 2, CH 4 and N 2 O) emissions, expressed as CO 2 -eq for three product chains: TIME and InStyle magazines and Canfor dimensional lumber (Figure 1). TIME is the largest weekly magazine in the U.S.A. with a guaranteed weekly production of 4,000,000 copies. InStyle, a monthly fashion magazine, has the greatest distribution of any other magazine in its category for ad pages. Canfor is the largest producer of softwood used to make dimensional lumber, and one of the largest producers of pulp in Canada, while Home Depot is the largest single retailer of dimensional lumber in North America. We determined the relative contribution of each process to the total net GHG emissions for each product chain and used the information to identify opportunities to reduce GHG emissions. The LCA of the magazine chain revealed that 1.17 and 1.11 t CO 2 eq. were emitted per ton of TIME and InStyle magazines produced, respectively (Figure 2), assuming 90% of unrecovered magazines were landfilled and 10% were incinerated. The relative contributions of the processes to the total net CO 2 -eq emissions were similar for Time and InStyle magazines, with the pulp and paper mill emissions comprising 61 to 77 % of the total emissions (Figure 2). CH 4 and N 2 O together comprised less than 1% of the total CO 2 -eq emissions for both magazines. 3

4 The life cycle analysis of the dimensional lumber chain revealed that 0.83 tco 2 -eq, was emitted per ton of dimensional lumber (Figure 3). CH 4 and N 2 O emissions comprised less than 0.5% of the total CO 2 -eq emissions. The transportation and distribution of dimensional lumber to consumer comprised the overwhelming percentage (94%) of the total GHG emissions (Figure 3). Indirect emissions comprised 98 % of total emissions for the dimensional lumber chain. This study is one of the first LCA studies to quantify GHG emissions of a major paper and wood product, and is unique from other studies because we largely used process-specific data provided by participants of the study. We examined only one year because it was the only year that all participants had the data required to complete the LCA. It is difficult to determine if the results and conclusions of the study would differ if another year were selected. The question of how representative this study is of other paper and dimensional lumber chains simply cannot be answered because other studies of similar LCA boundaries are lacking. It seems reasonable to assume that the GHG shadows calculated for TIME and InStyle are representative of other magazines in the U.S.A. because Time Inc. is the largest magazine publisher in the U.S.A. and the two magazines have very large distribution relative to other news and fashion magazines. Likewise, Canfor produces more dimensional lumber than any other company in Canada. Additional wood and paper product LCA studies are needed, and they should explicitly define the boundaries of the product chain to ensure valid comparisons. Life cycle analysis (LCA) of the GHG emissions for the magazine and dimensional lumber chains provided information required to identify management opportunities that can be implemented to reduce net GHG emissions. The U.S.A. pulp and paper industry accounts for 3% of the total national energy use. One opportunity for reducing direct GHG emissions from the magazine chain is increased pulp and paper mill production efficiency. In this study pulp and paper mill emissions comprised 61 to 77% of the total 4

5 GHG emissions for the two magazine chains. Total energy consumption per ton of pulp and paper output has decreased 0.8% /year between 1976 and If this historical trend is representative of potential future reductions, the pattern suggests that improved efficiency will result in only modest reductions in GHG emissions. Increased efficiency of the recovery of subscription magazines and magazine newsstand sales are two additional opportunities for reducing net GHG emissions for magazines. On average, only 10 to 17% of subscription magazines in the U.S. are recovered and recycled, with the balance being placed in landfills or incinerated 20. Increased recycling reduces the need to harvest additional trees that can continue to sequester CO 2 and reduces the loss of land to landfills 19. For 2001, 65 and 41 % of the Time and InStyle magazines, respectively, delivered to the newsstands were not sold 21. Even a 50% reduction in the production of surplus magazines would be of similar magnitude to the reported 20-25% increased CO 2 uptake by trees grown in elevated atmospheric CO 2 environment 3. This significant opportunity to reduce total GHG emissions can only occur if consumers purchasing and recycling habits are modified. The greatest opportunity to reduce GHG emissions for the dimensional lumber chain is to reduce transportation emissions, which constituted 94% of the total emissions. Opportunities for reducing GHG emissions from transportation include maximizing efficiency of transportation modes (e.g. truck vs. rail) and routes, and working with transportation providers to encourage fuel-efficient engine designs. Other opportunities for reducing dimensional lumber chain GHG emissions include increased: (i) energy use efficiency, (ii) production efficiency of older sawmills, (iii) substitution of renewable fuels to replace fossil fuels, and (iv) utilization of combined heat and power production. Greenhouse gas emissions also can be reduced by replacing fossil fuel energy sources by carbon neutral sources, such as hydro-electric, wind, solar, and nuclear energy. 5

6 Humans dominate the biological carbon cycle 22. Here we illustrate the linkage between the biological and industrial carbon cycle, and report GHG shadows for several forest products that are part of the industrial forest cycle. Consumers, governments, and society can all help reduce the GHG emissions from the industrial forest C cycle. The feasibility to reduce GHG emissions of forest product chains, which are clearly net sources for GHG contrary to previous studies , depends upon market forces and social acceptance. Methods. The wood fiber used by StoraEnso North America (SENA) to make the magazine paper for Time and InStyle magazines was obtained from forests in the Black Hills region of the U.S., the Great Lakes regions of the U.S. and Ontario, Canada (Figure 1). SENA also purchases kraft pulp from (i) Canfor s Interconn pulp mill that uses wood fiber from the Chetwynd Forest in interior British Columbia, Canada, and (ii) an additional 22% of their annual kraft pulp is obtained from other Canadian pulp mills. We assume that the GHG emissions for the other sources of kraft pulp are similar to Canfor s kraft pulp GHG shadow. The wood for the dimensional lumber was obtained from the Chetwynd Forest. The LCA included GHG emissions from harvest, transportation of wood and other raw materials to the mills, manufacturing emissions, transportation of finished products to end user (including the transportation to converter stations), recovery and recycling of products, and disposal of waste (Table 1). The GHG emissions were calculated using standard protocols and classified as direct or indirect 17. This study differs from other LCA for forest product chains because the data for each process in each chain, except for data used to estimate final fate of paper and dimensional lumber, are specific to the product, and are not national or international averages provided by commercially available LCA software. 6

7 The greenhouse gases considered in this study were carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O). Methane and nitrous oxide emissions were multiplied by 21, and 310, respectively 13-14, to account for their greater global warming potential than CO 2. CO 2 equivalent, henceforth denoted as CO 2 -eq, was calculated as the sum of CO 2 plus the weighted sum of CH 4 and N 2 O. Manuscript submitted December 14,

8 References. 1. Intergovernmental Panel on Climate Change (IPCC) Third assessment report (TAR), climate change 2001: The scientific basis. Working Group 1 Report, Technical Summary. IPCC National Greenhouse Gas Inventory. 2. Schlesinger, WH. Biogeochemistry. An analysis of global change. Academic Press, San Diego, CA. (1997) 3. Gower, S.T Patterns and mechanisms of the forest carbon cycle. Ann. Rev. Energy Environ. 28, Fan, S. et al. A large carbon sink in North America implied by atmospheric and oceanic carbon dioxide data and models. Science 282, (1998). 5. Bosquet, P., Peylin, P., Ciais, P., Quéré, C.L., Friedlingstein, P., Tans, P.P. Regional changes in carbon dioxide fluxes of land and oceans since Science 290, (2000). 6. Schimel, D. et al. Contribution of increasing CO 2 and climate to carbon storage by ecosystems in the United States. Science 287, Schimel, D.S. et al. Recent patterns and mechanisms of carbon exchange by terrestrial ecosystems. Nature 414, PPI. International fact and price book Brussels: Miller Freeman. 9. Karjalainen, T, Kellomaki, S., Pussinen, A Role of wood-based products in absorbing atmospheric carbon. Silva Fennica 28, Row, C., Phelps, R.B. Wood carbon flows and storage after timber harvest. R.N. Sampson and D. Hair (eds.) Forests and Global Change. Vol. 2. Forest Management opportunities for mitigating carbon emissions. American Forests, 8

9 Washington, DC pp (1996). 11. Winjum, J.K., Brown, S., and Schlamadinger, B. Forest harvests and wood products: sources and sinks of atmospheric carbon dioxide. For. Sci. 44, (1998). 12. Graedel, T.E., Allenby, B.R. Industrial Ecology. AT&T. Prentice Hall, Upper Saddle River, NJ. 412 pp. (2003). 13. U.S. Department of Energy (DOE). Instructions for form EIA-1605, voluntary reporting of greenhouse gases for data through OMB US DOE Energy Information Administration, Washington, DC, 65 p. (2002). 14. NCASI (National Council for Air and Stream Improvement) Calculation tools for estimating greenhouse gas emissions from pulp and paper mills. Version 1. Raleigh, NC. 15. Paper Task Force. Paper Task Force recommendations for purchasing and using environmentally preferable paper. The Environmental Defense Fund. 245 p. (1995). 16. Skog, KE and GA Nicholson. Carbon sequestration in wood and paper products. Chapter 5. In USDA Forest Service General Technical Report RMRS-GTR-59. Washington, DC (2000). 17. World Business Council for Sustainable Development (WBCSD). The greenhouse gas protocol: a corporate accounting and reporting standard. ISBN Switzerland (2001). 18. D. Reifkin, unpublished data (2004). 19. Ruth, M. and T. Harrington, Jr Dynamics of material and energy use in 9

10 U.S. Pulp and Paper Manufacturing. J. Indust. Ecol. 1, Denison, R.A. Environmental life-cycle comparisons of recycling, landfilling, and incineration: A review of recent studies. Ann. Rev. Energy Environ. 21, (1996). 21. Gower, S.T., Mckeon-Ruediger, A., Reitter, A., Bradley, M., Taup, A., Tollefson, T., Souba Jr., A.F., Reifkin, J.D., Embury-Williams, L., Schiavone, S., Weinbauer, J., Janetos, A., and, Johnston, K. Greenhouse gas life cycles for a magazine and dimensional lumber chains. J. Indust. Ecol. (in preparation). 22. Vitousek, PM, Mooney, H.A., Lubchenco, J., and Melillo, J.M. Human domination of the Earth s ecosystems Science 277, (1997). Correspondence and requests for materials should be addressed to S.T. Gower ( stgower@wisc.edu). 10

11 Figure 1. A schematic diagram illustrating the magazine and dimensional lumber chains examined in this study. SENA paper is tracked for a weekly magazine (TIME), that is printed at six printers, and monthly magazine (InStyle), that is printed at one printer, both of which are produced by Time Inc. Dimensional wood from the Chetwynd Forest is tracked for Home Depot dimensional lumber and other wholesale dimensional lumber, and waste products from the Chetwynd sawmill are tracked to their end fate. Solid lines represent fluxes that were measured by participants in the study and dashed lines depict fluxes that were estimated using industry-wide values. Figure 2. Relative and absolute CO 2 eq emissions for TIME (solid bars) and InStyle (open bars) magazines. Analyses were restricted to 2001 because this was the most recent year that data for all the processes were available. Processes include management + harvest (H), transportation to mill (TM), mill emissions (ME), transportation of paper to printer (TP), printer emissions (PE), transportation to consumer (TC) and final fate (FF). Figure 3. Relative and absolute CO 2 eq emissions for the dimensional lumber chain. Analyses were restricted to 2001 because this was the most recent year that data for all the processes were available. Definitions of life cycle processes are provided in Figure 3. 11

12 All correspondences should be directed to Dr. S.T. Gower (608) , 12

13 Figure 1. Gower et al. 2004

14 H TM ME TP PE TC FF Figure 2. Gower et al fraction of total CO2-eq emissions t CO2-eq/t magazine) H TM ME TP PE TC FF Total Process in magazine chain

15 Figure 3. Gower et al. CO2-eq/t lumber fraction of total H TM ME TC FF Process