In considering GHG emissions, there are a number of areas where equity is important. In common language equity means "the quality of being impartial" or "something that is fair and just". One example of the relevance of equity to GHG emissions are the different ways in which emissions can be measured. These include the total annual emissions of one country, cumulative emissions measured over long time periods (sometimes measured over more than 100 years), average emissions per person in a country (per capita emissions), as well as measurements of energy intensity of GDP, carbon intensity of GDP, or carbon intensity of energy use (discussed earlier). Different indicators of emissions provide different insights relevant to climate change policy, and have been an important issue in international climate change negotiations (e.g., see Kyoto Protocol#Negotiations).