Layers of methane are locked under permafrost in Arctic regions, but if they were released it could cause problems for the rest of the world. Researchers also discovered intense methane emissions deep in the Baltic Sea. Methane can be a real problem for the environment. The greenhouse gas, made up of carbon and hydrogen and about 80 percent more potent than carbon dioxide, occurs naturally in sedimentary layers of the seafloor and is responsible for about 30 percent of global temperature rise.