There are three general classes of environmental implications from agriculture: (1) amenity implications; (2) habitat implications; and (3) ecological implications. Environmental "benefits" or "costs" from agriculture require a prior specification of the norm against which the status quo is to be compared. Agriculture is no longer simply an activity that produces commodities for local, regional, national, or international markets. Indeed, in the OECD countries, commodity abundance, not commodity scarcity, is the norm and so it is necessary to see agriculture as primarily a land management activity that provides (and supports) rural livelihoods, and that happens also to produce some marketable commodities. This fundamental redefinition of agriculture allows us to escape the conceptual trap that seems to prevail in many discussions about the environmental attributes of agriculture. That conventional view holds that there is some normal structure of agriculture in each ecological setting which gives rise to some "natural" level of costs of production. This thinking then allows a seamless transition into a discussion of subsidies and "distortions" that contravene some inherent comparative advantage. Recent preoccupation with revising world trade arrangements has tended to reinforce such thinking.