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During the United Nations Climate Change Conference (COP26) in late 2021, our executive chairman Thomas Spangler highlighted the need for nations to include nitrous oxide (N2O) emissions in future climate plans. Overall tracking of emissions and the plans that have been released since are improving, but N2O continues to be a side note. However, understanding the significance of N2O underscores the importance of addressing it– and what CleanBay Renewables is doing to combat it.

What is nitrous oxide?

N20 is a chemical compound that is widely used across many sectors but is most notable for its use in medicine as an anesthetic – popularly known as “laughing gas”. However, it is 10 times more potent than methane, 300 times more potent than carbon dioxide and the EPA estimates it can stay in the atmosphere for 150 years.

Where does nitrous oxide come from?

Sources of N20 include fuel combustion, wastewater management, industrial processes and agriculture. The latter is the most significant producer of nitrous oxide with over 75 percent of all N20 emissions from human activity attributed to agriculture in the United States.

Agricultural nitrous oxide is strictly a microbial output, which means it is created by microbes – the very small, living things that can only be seen with a microscope.  The microbes found in agricultural soils produce N20 almost exclusively from interacting with a chemical compound called nitrate(s), which are comprised of nitrogen and oxygen molecules and are the most widespread form of nitrogen fertilizer pollution in the environment.  So, when nitrogen levels are high, more N20 is created. This nitrous oxide from the agricultural sector—specifically from the use of nitrogen fertilizers— caused over 70% of global N20 emissions in the recent decade (2007–2016).

What are the effects of nitrous oxide?

Like other greenhouse gases, nitrous oxide absorbs radiation and traps heat in the atmosphere. Of the three primary GHGs, it is the most potent. However, nitrous oxide also stands alone as the only major greenhouse gas that also destroys the ozone layer.

Nitrous oxide is uniquely challenging in part because it is a fairly unreactive gas that is not water-soluble and does not absorb visible radiation, only ultraviolet (UV). So, after human activities or microbes generate it, the N2O must float all the way to the stratosphere before it can absorb enough UV radiation to decompose back into nitrogen and oxygen. This is why the atmospheric lifetime of N2O is estimated to be about 150 years. Unfortunately, some of this N2O will not break back down to its original components and will instead be oxidized to NOx, which then destroys ozone and contributes to growing ozone holes that let damaging radiation through the atmosphere.

Nitrous oxide is also released from uncontrolled agriculture byproducts, like raw animal manures. Only about half of the nitrogen released from land-applied, uncontrolled poultry litter can be used by plants, the rest may be washed away. Excess nitrogen in the water supply leads to algae blooms, polluting local waterways and creating dead zones.

How to combat nitrous oxide?

There is very little we can do regarding these stratospheric conversions of N2O, but microbial production and microbial conversion of N2O can be influenced and are critically important for designing appropriate GHG mitigation measures.

The wide-ranging effects of nitrous oxides – air, soil and water pollution – is why private sector companies like CleanBay are stepping in to provide immediate solutions. Using a proprietary combined anaerobic digestion and nutrient recovery process, CleanBay can recycle more than 150 thousand tons of poultry litter per full scale facility each year to create a renewable natural gas and natural controlled-release fertilizers. This process not only recycles poultry litter from farms – avoiding the nitrous oxide emissions noted above – but the fertilizers are designed to improve plant utilization and reduce microbial nitrogen conversions, offering a critical improvement over highly soluble, reactive fertilizers. The clean energy and fertilizer created from this agricultural byproduct can reduce greenhouse gas emissions by up to 1,000,000 tons of CO2 equivalent annually and more precisely provide plants with essential nutrients, avoiding the microbial creation of N2O in the first place.

Multipurpose, government satellites; tower-based sensors; airborne monitoring; global data sharing agreements; incentives to take advantage of such technologies; and organized carbon markets are many of the other options available to help us address N20 emissions. But we cannot wait for sustained funding or rely only on carbon and methane emissions reductions to meet our immediate climate needs.

Next steps – for companies, for farmers and for nations –need to happen now, need to be holistic, and need to include plans to reduce N20.

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