An ecotax (short for ecological taxation) is a tax levied on activities which are considered to be harmful to the environment and is intended to promote environmentally friendly activities via economic incentives. Such a policy can complement or avert the need for regulatory (command and control) approaches. Often, an ecotax policy proposal may attempt to maintain overall tax revenue by proportionately reducing other taxes (e.g. taxes on human labor and renewable resources); such proposals are known as a green tax shift towards ecological taxation. Ecotaxes address the failure of free markets to consider environmental impacts.Ecotaxes are examples of Pigouvian taxes, which are taxes that attempt to make the private parties involved feel the social burden of their actions. An example might be philosopher Thomas Pogge's proposed Global Resources Dividend.