A3 Emissions Scenarios for the IPCC: an Update Masters, C.D., D.H. Root and E.D. Attanasi, 1991: Resource constraints in petroleum production potential. Science, 253. 146-152. Nordhaus, W.D. and G.W. Yohe, 1983: Future Carbon Dioxide Emissions from Fossil Fuels. In: Changing Climate. National Swart, R.J., W.J. Pepper. C. Ebert and J. Wasson, 1991: United Nations, 1990: Population Prospects 1990. United United Nations, 1992: Long-Range World Population Weyant, J., 1991: Stanford Energy Modeling Forum. Personal WMO, 1992: Scientific Assessment of Ozone Depletion. World Bank. 1991: World Development Report 1991. Oxford Zachariah, K.C. and M.T. Vu. 1988: World Population Projections 1987-88 Edition. Johns Hopkins University Press. 95 INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE CLIMATE CHANGE 1992 Report Prepared for IPCC by Working Group I Edited by J.T.Houghton, B.A.Callander and S.K.Varney (Meteorological Office, Bracknell, United Kingdom) Valuation of Ecosystems Q11. On page 8 of your written testimony you state that “Initial estimates of the total value of global ecosystem services suggest they could be in the trillions of dollars annually." Please document this statement. All. Attached is a paper called "The value of the world's ecosystem services and natural capital," by Robert Costanza, et al., which was published in Volume 387 of Nature on May 15, 1997. This paper represents an innovative multidisciplinary approach to estimating the value of the services provided by ecological systems. In it, the authors, who are ecologists and economists, estimate the current economic value of 17 ecosystem services for 16 biomes to be in the range of $1654 trillion per year. Note that the authors state that "Because of the nature of the uncertainties, this must be considered a minimum estimate." articles The value of the world's ecosystem services and natural capital Robert Costanza'†, Ralph d'Arge‡, Rudolf de Groots, Stephen Farber, Monica Grassoţ, Bruce Hannons, Karin Limburgs", Shahid Naeem**, Robert V. O'Neill††, Jose Paruelo‡‡, Robert G. Raskin§§, Paul Sutton||| & Marjan van den Belt¶¶ *Center for Environmental and Estuarine Studies, Zoology Department, and ↑ Insitute for Ecological Economics, University of Maryland, Box 38, Solomons, Maryland 20688, USA * Economics Department (emeritus), University of Wyoming, Laramie, Wyoming 82070, USA $ Center for Environment and Climate Studies, Wageningen Agricultural University, PO Box 9101, 6700 11B Wageninengen, The Netherlands Graduate School of Public and International Affairs, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA 1 Geography Department and NCSA, University of Illinois, Urbana, Illinois 61801, USA • Institute of Ecosystem Studies, Millbrook, New York, USA ** Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, Minnesota 55108, USA ↑↑ Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA 11 Department of Ecology, Faculty of Agronomy, University of Buenos Aires, Av. San Martin 4453, 1417 Buenos Aires, Argentina 45 let Propulsion Laboratory, Pasadena, California 91109, USA USA National Center for Geographic Information and Analysis, Department of Geography, University of California at Santa Barbara, Santa Barbara, California 93106, 99 Ecological Economics Research and Applications Inc., PO Box 1589, Solomons, Maryland 20688, USA The services of ecological systems and the natural capital stocks that produce them are critical to the functioning of the Earth's life-support system. They contribute to human welfare, both directly and indirectly, and therefore represent part of the total economic value of the planet. We have estimated the current economic value of 17 ecosystem services for 16 biomes, based on published studies and a few original calculations. For the entire blosphere, the value (most of which is outside the market) is estimated to be in the range of US$16–54 trillion (101) per year, with an average of US$33 trillion per year. Because of the nature of the uncertainties, this must be considered a minimum estimate. Global gross national product total is around US$18 trillion per year. Because ecosystem services are not fully 'captured' in commercial markets or adequately quantified in terms comparable with economic services and manufactured capital, they are often given too little weight in policy decisions. This neglect may ultimately compromise the sustainability of humans in the biosphere. The economies of the Earth would grind to a halt without the services of ecological life-support systems, so in one sense their total value to the economy is infinite. However, it can be instructive to estimate the 'incremental' or 'marginal' value of ecosystem services (the estimated rate of change of value compared with changes in ecosystem services from their current levels). There have been many studies in the past few decades aimed at estimating the value of a wide variety of ecosystem services. We have gathered together this large (but scattered) amount of information and present it here in a form useful for ecologists, economists, policy makers and the general public. From this synthesis, we have estimated values for ecosystem services per unit area by biome, and then multiplied by the total area of each divine and summed over all services and biomes. Although we acknowledge that there are many conceptual and empirical problems inherent in producing such an estimate, we think this exercise is essential in order to: (1) make the range of potential values of the services of ecosystems more apparent; (2) establish at least a first approximation of the relative magnitude of global ecosystem services; (3) set up a framework for their further analysis; (4) point out those areas most in need of additional research; and (5) stimulate additional research and debate. Most of the problems and uncertainties we encountered indicate that our *Present sodrem: Department of Systems Ecology, University of Stockholm, 5-106 91 Stockholm, Sunder estimate represents a minimum value, which would probably increase: (1) with additional effort in studying and valuing a broader range of ecosystem services; (2) with the incorporation of more realistic representations of ecosystem dynamics and interdependence; and (3) as ecosystem services become more stressed and 'scarce' in the future. Ecosystem functions and ecosystem services Ecosystem functions refer variously to the habitat, biological or system properties or processes of ecosystems. Ecosystem goods (such as food) and services (such as waste assimilation) represent the benefits human populations derive, directly or indirectly, from ecosystem functions. For simplicity, we will refer to ecosystem goods and services together as ecosystem services. A large number of functions and services can be identified. Reference 5 provides a recent, detailed compendium on describing, measuring and valving ecosystem services. For the purposes of this analysis we grouped ecosystem services into 17 major categorics. These groups are listed in Table 1. We included only renewable ecosystem services, excluding non-renewable fuels and minerals and the atmosphere. Note that ecosystem services and functions do not necessarily show a oneto-one correspondence. In some cases a single ecosystem service is the product of two or more ecosystem functions whereas in other cases a single ecosystem function contributes to two or more ecosystem services. It is also important to emphasize the interdependent nature of many ecosystem functions. For example, some of the net primary production in an ecosystem ends up as food, the consumption of which generates respiratory products necessary for primary production. Even though these functions and services are interdependent, in many cases they can be added because they represent 'joint products' of the ecosystem, which support human articles welfare. To the extent possible, we have attempted to distinguish joint and a 'dable' products from products that would represent 'double counting' (because they represent different aspects of the same service) if they were added. It is also important to recognize that a miniinum level of ecosystem 'infrastructure' is necessary in order to allow production of the range of services shown in Table 1. Several authors have stressed the importance of this 'infrastructure' of the ecosystem itself as a contributor to its total value. This component of the value is not included in the current analysis. Natural capital and ecosystem services In general, capital is considered to be a stock of materials or information that exists at a point in time. Each form of capital stock generates, either autonomously or in conjunction with services from other capital stocks, a flow of services that may be used to transform materials, or the spatial configuration of materials, to enhance the welfare of humans. The human use of this flow of services may or may not leave the original capital stock i act. Capital stock takes different identifiable forms, most notably in physical forms including natural capital, such as trees, minerals, ecosystems, the atmosphere and so on, manufactured capital, such as machines and buildings; and the human capital of physical bodies. In addition, capital stocks can take intangible forms, especially as information such as that stored in computers and in individual human brains, as well as that stored in species and ecosystems. Ecosystem services consist of flows of materials, energy, and information from natural capital stocks which combine with manufactured and human capital services to produce human welfare. Although it is possible to imagine generating human welfare without natural capital and ecosystem services in artificial 'space colonies, this possibility is too remote and unlikely to be of |