Microbial contribution to and amelioration of enteric methane emissions from domestic herbivores

Abstract

Global climate change is a major issue currently facing the international community. The primary cause of climate change arises from the human-induced increase in emission of the ‘greenhouse’ gases, primarily carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). In animal agriculture, CH4 and N2O emissions predominate, especially CH4. The largest source of CH4 in the world is enteric methane from livestock (cattle and sheep), with enteric CH4 accounting for 28% of total methane emissions. In countries reliant on agriculture for export earnings, such as Australia and New Zealand, enteric CH4 is the major greenhouse gas from the agriculture sector and a significant contributor to total emissions (50% of New Zealand’s and 14% of Australia’s). Reducing CH4 emissions is highly advantageous in delivering climate benefits in the shorter-term as CH4 has a high radiative forcing potential (21 times that of CO2) but a short atmospheric life (about 10 years), compared to 100 years for CO2.