Multiple negotiating rounds of the General Agreement on Tariffs and Trade (GATT) and World Trade Organization (WTO) since 1947 have conferred economic benefits through liberalized international trade. A growing body of evidence also points to linkages between liberalized trade and damage to the global environment, ecology, and natural resource base. Ironically, the increased economic well-being conferred by trade liberalization ultimately provides the basis for improved environmental protection. It is the interim environmental damage due to trade liberalization that is controversial and needing amelioration. The proposition here is to promote further trade liberalization, but only as long as environmental ethics and sustainability issues are satisfactorily addressed. Trade liberalization should not be permitted at the expense of adequate environmental protection and sustainability. Future WTO rounds need to address both development benefits and environmental ethics issues in a net social welfare maximization setting.