hydroxyl radical

Theoretically, hydrogen could be the fuel of the future. It is the most common element in the universe and its combustion produces no harmful emissions. Most industrial hydrogen comes from a process called steam reforming that extracts it from natural gas – basically methane. Carbon dioxide is a byproduct of the process. But it is also possible to get hydrogen by breaking down water resulting only in oxygen as a byproduct. There is a great deal of ongoing development of so-called green hydrogen.

New research from Princeton University and the National Oceanic and Atmospheric Administration has uncovered a potential problem associated with the use of hydrogen as a clean fuel.

There is a molecule in the atmosphere called the hydroxyl radical. It is known as “the detergent of the troposphere”. It plays a critical role in eliminating greenhouse gases such as methane and ozone from the atmosphere. It turns out that the hydroxyl radical also reacts with any hydrogen gas in the atmosphere and there is only so much hydroxyl to go around. If large amounts of hydrogen were to enter the atmosphere, much of the hydroxyl radical would be used up reacting with it and there would be much less available to break down methane. As a result, there would end up being more methane in the atmosphere, and methane is a powerful greenhouse gas.

The bottom line is that there would need to be proactive efforts to limit the amount of hydrogen getting into the atmosphere whether from producing it, transporting it, or anyplace else in the value chain. Otherwise, the hydrogen economy would cancel out many of the climate benefits of eliminating fossil fuels.

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Switching to hydrogen fuel could prolong the methane problem

Photo, posted June 12, 2021, courtesy of Clean Air Task Force via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The early months of the COVID-19 pandemic saw drastic reductions in travel and other economic sectors across the globe that greatly decreased air pollution and greenhouse gas emissions. These dramatic changes occurred quite suddenly. This abrupt set of changes gave scientists the unprecedented opportunity to observe the results of changes that would ordinarily have taken years if they came about through regulations and gradual behavior shifts.

A comprehensive study by Caltech on the effects of the pandemic on the atmosphere has revealed some surprising results.

The biggest surprise is that even though carbon dioxide emissions fell by 5.4% in 2020, the amount of CO2 in the atmosphere continued to grow at about the same rate as in previous years. According to the researchers, the reasons are that the growth in atmospheric concentrations was within the normal range of year-to-year variations caused by natural processes and, in addition, the ocean did not absorb as much CO2 because of the reduced pressure of CO2 in the air at the ocean’s surface.

A second result involved the reduction in nitrogen oxides, which led to a reduction in a short-lived molecule called the hydroxyl radical, which is important in breaking down gases including methane in the atmosphere. Reducing nitrogen oxides is advantageous with respect to air pollution, but they are important for the atmosphere’s ability to cleanse itself of methane. In fact, the drop in nitrogen oxide emissions actually resulted in a small increase of methane in the atmosphere because it was staying there longer.

The main lesson learned is that reducing activity in industrial and residential sectors is not a practical solution for cutting emissions. The transition to low-carbon-emitting technology will be necessary.

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Emission Reductions From Pandemic Had Unexpected Effects on Atmosphere

Photo, posted March 22, 2020, courtesy of Greg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hydrogen And The Methane Problem | Earth Wise

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Emissions And The Pandemic | Earth Wise

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