Query: While methane is a more potent greenhouse gas than CO2, there is over 200 times more CO2 in the atmosphere.

Relevant passages:
Atmospheric methane <=SEP=> Atmospheric methane is the methane present in Earth 's atmosphere . Atmospheric methane concentrations are of interest because it is one of the most potent greenhouse gases in Earth 's atmosphere . The 100-year global warming potential of methane is 28 . That is , over a 100-year period , it traps 28 times more heat per mass unit than carbon dioxide and 32 times the effect when accounted for aerosol interactions . Global methane levels , had risen to 1800 parts per billion ( ppb ) by 2011 , an increase by a factor of 2.5 since pre-industrial times , from 722 ppb , the highest value in at least 800,000 years . Its concentration is higher in the Northern Hemisphere since most sources ( both natural and human ) are located on land and the Northern Hemisphere has more land mass . The concentrations vary seasonally , with , for example , a minimum in the northern tropics during April − May mainly due to removal by the hydroxyl radical .   Early in the Earth 's history carbon dioxide and methane likely produced a greenhouse effect . The carbon dioxide would have been produced by volcanoes and the methane by early microbes . During this time , Earth 's earliest life appeared . These first , ancient bacteria added to the methane concentration by converting hydrogen and carbon dioxide into methane and water . Oxygen did not become a major part of the atmosphere until photosynthetic organisms evolved later in Earth 's history . With no oxygen , methane stayed in the atmosphere longer and at higher concentrations than it does today .   Methane is created near the surface , and it is carried into the stratosphere by rising air in the tropics . Uncontrolled build-up of methane in Earth 's atmosphere is naturally checked -- although human influence can upset this natural regulation -- by methane 's reaction with hydroxyl radicals formed from singlet oxygen atoms and with water vapor .

Natural gas <=SEP=> Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane , but commonly including varying amounts of other higher alkanes , and sometimes a small percentage of carbon dioxide , nitrogen , hydrogen sulfide , or helium . It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years . The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas .   Natural gas is a fossil fuel used as a source of energy for heating , cooking , and electricity generation . It is also used as fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals . Fossil fuel based natural gas is a non-renewable resource .   Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates . Petroleum is another resource and fossil fuel found in close proximity to and with natural gas . Most natural gas was created over time by two mechanisms : biogenic and thermogenic . Biogenic gas is created by methanogenic organisms in marshes , bogs , landfills , and shallow sediments . Deeper in the earth , at greater temperature and pressure , thermogenic gas is created from buried organic material .   In petroleum production gas is often burnt as flare gas . The World Bank estimates that over 150 cubic kilometers of natural gas are flared or vented annually . Before natural gas can be used as a fuel , most , but not all , must be processed to remove impurities , including water , to meet the specifications of marketable natural gas . The by-products of this processing include : ethane , propane , butanes , pentanes , and higher molecular weight hydrocarbons , hydrogen sulfide ( which may be converted into pure sulfur ) , carbon dioxide , water vapor , and sometimes helium and nitrogen .   Natural gas is often informally referred to simply as `` gas '' , especially when compared to other energy sources such as oil or coal . However , it is not to be confused with gasoline , especially in North America , where the term gasoline is often shortened in colloquial usage to gas .   Natural gas was used by the Chinese in about 500 BCE ( possibly even 1000 BCE ) . They discovered a way to transport gas seeping from the ground in crude pipelines of bamboo to where it was used to boil salt water to extract the salt , in the Ziliujing District of Sichuan . The world 's first industrial extraction of natural gas started at Fredonia , New York , United States in 1825 . By 2009 , 66 000 km ³ ( or 8 % ) had been used out of the total 850 000 km ³ of estimated remaining recoverable reserves of natural gas . Based on an estimated 2015 world consumption rate of about 3400 km ³ of gas per year , the total estimated remaining economically recoverable reserves of natural gas would last 250 years at current consumption rates . An annual increase in usage of 2 -- 3 % could result in currently recoverable reserves lasting significantly less , perhaps as few as 80 to 100 years .