【正文】 in modifying national ine accounting systems to promote understanding of the links between economy and environment.The field of environmental accounting has made great strides in the past two decades, moving from a rather arcane endeavor to one tested in dozens of countries and well established in a few. But the idea that nations might integrate the economic role of the environment into their ine accounts is neither a quick sell nor a quick process。 it has been under discussion since the 1960s. Despite the difficulties and controversies described in this article, however, interest is growing in modifying national ine accounting systems to promote understanding of the links between economy and environment.Why Change?Governments around the world develop economic data systems known as national ine accounts to calculate macroeconomic indicators such as gross domestic product. Building a nation’s economic use of the environment into such accounts is a response to several perceived flaws in the System of National Accounts (SNA), as defined by the United Nations and used internationally. One flaw in the SNA often cited is that the cost of environmental protection cannot be identified. Consequently, money spent, say, to put pollution control devices on smokestacks increases GDP, even though the expenditure is not economically productive, some argue. These critics call for differentiating “defensive” expenditures from others within the accounts. Also misleading is the fact that some environmental goods are not marketed though they provide economic value. Fuel wood gathered in forests, meat and fish gathered for consumption, and medicinal plants are examples. So are drinking and irrigation water, whose sale prices reflect the cost of distribution and treatment infrastructure, but not the water itself. While some countries do include such goods in their national ine accounts, no standard practices exist for doing so. When nonmarket goods are included in the accounts, they still cannot be distinguished from those that are marketed. Valuing environmental services such as the watershed protection that forests afford and the crop fertilization that insects provide is difficult. Though some experts call for their inclusion in environmentally adjusted accounts, typically neither the economic value nor the degradation of these services is included. On the other hand, however, the alternate goods and services needed to replace those— water treatment plants, for example—do contribute to GDP, which can be rather misleading. Still another problem is that national ine accounts treat the depreciation of manufactured capital and natural capital differently. Physical capital—a building or a machine, for instance—is depreciated in accordance with conventional business accounting principles, while all consumption of natural capital is accounted for as ine. Thus the accounts of a country that harvests its forests unsustainably will show high ine for a few years, but will not reflect the destruction of the productive forest asset. While opinions vary on how to depreciate natural capital, they converge on the need to do so.Which Indicators Are Useful?Some proponents advocate simple “flag” indicators to alert policymakers to the broad role of the environment in the economy, for example, paring conventionalGDP with environmentally adjusted GDP, or conventional savings with socalled “genuine” savings that account for environmental factors. Both of these indicators can provide valuable warnings of the impacts of environmental degradation on an economy. However, such flags are less useful in determining the source of environmental harm or identifying a policy response. For this reason, many economists place primary importance not on the bottom line, but on the underlying data used to build environmental accounts. These data can help answer such questions as how natural catastrophes like the fires that raged in Indonesia in the summer of 1998 may affect economic growth, or how environmental protection policies such as green taxes may affect the economy.Who Is Doing This?Environmental accounting is underway in several dozen countries, where bureaucrats, statisticians, and other proponents both foreign and domestic have initiated activities over the past few decades. Several countries have made continuous investments in building routine data systems, which are integrated into existing statistical systems and economic planning activities. Others have made more limited efforts to calculate a few indicators, or analyze a single sector. Some of the earliest research on environmental accounting was done at RFF by Henry Peskin, working on the design of accounts for the United States. One of the first countries to build environmental accounts is Norway, which began collecting data on energy sources, fisheries, forests, and minerals in the 1970s to address resource scarcity. Over time, the Norwegians have expanded their accounts to include data on air pollutant emissions. Their accounts feed into a model of the national economy, which policymakers use to assess the energy implications of alternate growth strategies. Inclusion of these data also allows them to anticipate the impacts of different growth patterns on pliance with international conventions on pollutant emissions. More recently, a number of resourcedependent countries have bee interested in measuring depreciation of their natural assets and adjusting their GDPs environmentally. One impetus for their interest was the 1989 study “Wasting Assets: Natural Resources in the National Ine Accounts,” in which Robert Repetto and his colleagues at the World Resources Institute estimated the depreciation of Indonesia’s forests, petroleum reserves, and soil assets. Once adjusted to account for that depreciation, Indonesia’s GDP and growth rates both sank significantly below conventional figures. While “Wasting Assets” called many to action, it also opera