Hydrogen is a more potent greenhouse gas than previously reported, new study reveals
Indirect atmospheric warming effects of H2 shown with more certainty to be higher than ever, increasing climate risk of hydrogen leakage
The warming potential of hydrogen as an indirect greenhouse gas has been shown to be higher than previously reported and with a greater degree of certainty, according to a new study published today (Wednesday).
Hydrogen: hype, hope and the hard truths around its role in the energy transition
In practice this means that the GWP of atmospheric hydrogen could be between 8.8 and 14.4 depending on a range of factors, including how much hydrogen is absorbed into soil at ground level and how effectively it interacts with other airborne molecules that cause global heating.
Hydrogen is considered an indirect greenhouse gas because although it does not cause a warming effect on its own, it interacts with airborne molecules called hydroxyl radicals to prolong the lifetime of atmospheric methane — a highly potent greenhouse gas — and increase the production of ozone, another greenhouse gas.
The paper, which used five different modelling techniques to arrive at its conclusions instead of the typical one, also calculated that the GWP over 20 years for hydrogen is a whopping 37.3 ± 15.1, while over 500 years it is minimal at 3.31 ± 0.98.
GWP is measured against the warming potential of a kilogram of carbon dioxide, meaning that in the study’s central range, a kilogram of hydrogen would have the same warming effect as 11.6 kilograms of CO2.
Prior to this, the most frequently-cited paper estimated the GWP100 of hydrogen at just 5.8.
But significantly, the Oslo-led study, which also included work from the US government’s National Oceanic and Atmospheric Administration and France’s Université Paris-Saclay, as well as the University of California and the University of Edinburgh, came up with a smaller range around its central figure of 11.6, indicating a higher degree of certainty.
This could be because the researchers used five different global atmospheric modelling systems to arrive at their conclusion.
“It will be important to keep hydrogen leakages at a minimum to accomplish the benefits of switching to a hydrogen economy,” the study warned.
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