Input-Output Analysis of Philippine Sectoral CO 2 Emissions Raymond R. Tan, Ph.D. 1, Joel Q. Tanchuco, M.A. 2 1 Center for Engineering and Sustainable Development Research; 2 Economics Department De La Salle Unviersity-Manila, 2401 Taft Avenue, 1004 Manila, Philippines 1 Tel/Fax: ; Website: SUMMARY – Economic input-output (EIO) models combined with life cycle assessment (LCA) are used to estimate direct and indirect CO 2 emissions of different economic sectors in the Philippines. These results allow for comparison of carbon intensities of different sectors per unit of GDP contribution. WHAT IS EIO-LCA? Economic input-output analysis was developed by Leontief to quantify interactions within economies [1]. The method has been extended in the context of life cycle assessment to estimate direct and indirect emissions or resource use [2, 3]. NOMENCLATURE B = environmental emissions matrix g = inventory vector I = identity matrix y = final demand vector in EIO model Z = technology matrix in EIO model COMPUTATIONAL MODEL Emission balances can be computed for EIO-LCA using: g = B (I – Z) –1 y (Eq.1) DISCUSSION Figures 1 and 2 show the carbon intensities per thousand pesos output and emissions contributions of the 11 major economic sectors based on the 2000 input-output tables [4] and sectoral direct carbon emissions [5]. Table 1 shows the major indirect contributors for each of the sectors. For eight of the sectors, direct emissions account for just 20 – 40% of life cycle carbon releases. In the case of the utilities, transportation and real estate sectors, direct emissions are the dominant contributors. CONCLUSIONS The utilities and transport sectors are the most carbon- intensive sectors of the Philippine economy; direct emissions account for the bulk of the environmental flows for both. In addition, these also account for most of the indirect emissions of most of the other economic sectors. REFERENCES [1] Leontief, W Environmental repercussions and the economic structure. Review of Economics and Statistics 52: 262 – 271. [2] Heijungs, R. and Suh, S The computational structure of life cycle assessment. Kluwer, Dordrecht. [3] Hendrickson, C. T., Lave, L. B. and Matthews, H. S Environmental life cycle assessment of goods and services. An input-output approach. RFF Press, Washington, DC. [4] [5] ABOUT THE AUTHORS Dr. Raymond R. Tan is an associate professor of the Chemical Engineering Department of De La Salle University-Manila. He has worked on environmental systems modelling at the Center for Engineering & Sustainable Development Research since He received the 2004 OYS Award for his research on the life cycle analysis of alternative motor vehicle fuels. Joel Q. Tanchuco is an assistant professor of the Economics Department of De La Salle University-Manila. He specializes in energy and environmental economics. He can be contacted via at