Methane (IMAGE) Spanish National Research Council (CSIC) Caption Livestock farming is responsible for 18 percent of the world's greenhouse gases, and ruminants such as cattle, sheep and goats generate 35 percent of one of these gases -- methane, and according to experts they make a significant contribution to climate change. Credit Comunicación CSIC Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.