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