This paper looks at how contemporary environmental (including climate) policy problems are phrased in terms of effectiveness, efficiency, and equity. The latter three concepts have served as foci of theoretical discussions among economists who analyse these issues and identify criteria that determine relevant regulations and programmes adopted by governments. The paper starts with a discussion of Pigouvian taxation as model instrument used in order to solve policy problems. It analyses to what extent and under what circumstances alternative instruments — such as marketable pollution permits — can achieve environmental and climate goals while serving other purposes too. Coase theorem is used as a reference for discussing what government interventions are indeed indispensable to achieve both explicit and tacit policy goals. Popular principles and practically applied 'rules of thumb' — such as the Polluter Pays Principle — are then reviewed. The next part is devoted to examining market structures as they influence environmental outcomes of economic activities. This is followed by a discussion of Environmental Tax Reforms which seems to inspire much of the economic thinking about contemporary policies. An outlook for the 21st century concludes the paper.