GHG emissions are a major contributor to climate change and are governed by the UN ‘United Nations Framework Convention on Climate Change’ and the subsequent UN ‘Kyoto Protocol'. Some GHGs, including methane (CH4), are also air pollutants that have significant adverse impacts on ecosystems, air quality, agriculture, and human and animal health. As a result, different national and international regulations and incentive systems (such as tradable emission permits) aim to control the volume, and reward the reduction of GHG emissions.