For a number of reasons, however, adaptation has received less attention than mitigation in the discussions centred around climate change and it is only recently that efforts directed towards adaptation are being incorporated in the global policy agenda. First, as adaptation is a public good, private provision will typically remain below socially desirable levels unless the public sector intervenes. Second, adaptation, is difficult to address as it requires actions along the economic, social and environmental dimensions of development, which depend on the specific context of each country. Finally, there are no clear metrics for assessing adaptation impacts, that is, unlike mitigation, for which there is a clearly defined metric (namely, tons of greenhouse gas emissions), assessing adaptation efforts requires a larger number of indicators closely related to wider development efforts.