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Other Indirect Greenhouse Gases - Hydrogen

high altitude cloudsHydrogen (H2) is similar to carbon monoxide in that it acts as an indirect greenhouse gas through its effect on hydroxyl (OH) radicals. By reducing the levels of OH in the atmosphere, hydrogen increases the lifetime of some direct greenhouse gases, such as methane.

Much hydrogen is itself produced in the atmopshere by the oxidation of methane, with total global emisssions estimated to be about 70 million tonnes each year. As well as removal in the atmopshere by its reaction with OH, significant amounts of hydrogen are also taken up by soil microorganisms.

Human Impact

Currently man is responsible for around half of total hydrogen emissions, with the most important man-made source being fossil fuel burning. Overall, the indirect action of hydrogen as a greenhouse gas, through its reaction with OH radicals, is not currently of huge importance. However, future developments in hydrogen based power supplies could lead to substantial increases in hydrogen emissions.

Potential for control

Future development of hydrogen based fuel sources should include an awareness of hydrogen as an indirect greenhouse gas.


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