29 March 2022 |

Nitrous oxide – no laughing matter


In one of my popular newsletters this quarter (sent on 3/1; based on total open ratio), I wrote:

It took Russian aggression going from warm to hot for Western Europe to get serious about de-Russifying their energy sources. It’s important that the trend reaches beyond just diversifying where countries get their natural gas, however. Climate change hasn’t proved sufficiently concerning to elicit action; we probably won’t get as good a catalyst to reevaluate energy mixes again anytime soon.

Alongside energy security, another story that’s catching a lot of attention now is food security. For one, Ukraine is a massive wheat exporter. Perhaps even more importantly however, Russia is a huge exporter of fertilizer. The world is racing to onboard more fertilizer production capacity to keep global agriculture humming. But it may well be too little too late; there’s a lot of fear that fertilizer shortages will have long-tailed impacts on global food supply.

This email won’t explore that dynamic too closely. For one it’s not really my climate tech remit. Nor is it something I know a ton about. Nor do I need to add to the cacophony of concern.

That said, I will take the opportunity to take a look at another greenhouse gas that’s inextricably linked with fertilizer. Why? Because we don’t talk about it enough as is.

What am I on about? Nitrous oxide. Alongside reducing methane emissions, reducing nitrous oxide emissions would be a sure-fire way to decelerate global warming. 

As long as we’re talking fertilizer… let’s talk N20.


The agriculture sector catches plenty of flak for its greenhouse gas emissions. It’s a carbon dioxide intensive industry in its own right.

And of course, there’s no shortage of discussion of cow burps and the methane gas they release into the atmosphere. We covered Mootral, a company tackling that challenge head on. 

However, Nitrous oxide should be a big consideration when we talk about emissions from the agriculture sector too. N20 emissions represent ~6% GHG emissions, making it the third most prevalent GHG in the atmosphere. N20 emissions are also up ~36% since 1980.

Where do they come from? You guessed it. Fertilizer. Up to 2.5% of all greenhouse gas emissions are nitrous oxide emissions that come from synthetic nitrogen based fertilizer, which is primarily used on industrial scale farms. Specifically, soil microbes produce N20 (as part of a number of other complicated processes) when plants and crops don’t use all the nitrogen that’s available to them.

Binging: Global consumption of synthetic nitrogen fertilizer

To be sure, synthetic fertilizers are a miraculous product in a way. They’ve boosted crop yields magnificently, making it possible to feed a burgeoning global population.

But it takes more and more fertilizer to achieve similar growth over time. And the biggest industrial scale farming operations are often the biggest culprits, heaping inane amounts of fertilizer on crops to supercharge growth. In fact… 

[Only about] 20-30% of the synthetic fertilizers applied to fields are converted to foods, with the rest running off into water bodies and entering the environment as pollution. (here)

While there’s less N20 floating up into our atmosphere in terms of sheer volume than CO2, it has 300x the global warming potential of CO2 over a 100 year timespan. The GWP of methane over a similar timeframe is about 30x.

To simplify even further, for every pound of fertilizer used, 8 pounds of CO2e emissions are released into the atmosphere. Nitrogen and other chemicals also flow off farms into rivers, a problem so pernicious that ~50% of American rivers are too polluted for swimming, let alone for potable use.

To make matters worse, most fertilizer is produced with natural gas as a primary input, contributing CO2 and methane emissions to the atmosphere as well.

In sum, nitrous oxide emissions is a major contributor to climate change. Cutting down on nitrous oxide emissions would significantly help decelerate climate change in the short term, even more so than reducing CO2 emissions would.


Normally I’d try to propose swift solutions here to be optimistic about. I could write “farm differently.” And that’s a big component of the answer. But writing that with a few swift keystrokes almost felt… disingenuous considering just how dependent farming is on synthetic fertilizers.

Feeding the world is a good thing. And the world isn’t going to require less food and consequently less agriculture anytime soon. Demand is going to keep going up and to the right as the world population balloons via Africa and Asia.

But as with energy security… if ever there were a moment to spur innovation to make better alternatives to current nitrogen based fertilizers… then perhaps there’s something good to come out of the war in Ukraine yet. Why? Because fertilizer prices look like this: 

Ahh. Hadn’t used a FRED graph in an email in a while. My OG subscribers will be tickled.

If that doesn’t trigger a search for new solutions, I’m not sure what will. 

There are companies like Nitricity working to produce nitrogen fertilizer more sustainably (i.e. without fossil fuels). I’d have to dig deeper with them to understand whether their product helps reduce N2O emissions from overuse of fertilizer too. Fodder for another deep dive soon, perhaps.

In any case, this is an area ripe for innovation, with a massive market and massive CO2 emissions reduction potential. 

Zooming all the way out? Beyond fertilizer, if we’re gonna talk about food shortages, this thread was also a great reminder that climate risk = food & water risk, too. Whether it’s mega droughts in the Western U.S. or deteriorating crop conditions in China, the long-term concern is climate change, even if the short-term concern is fertilizer production capacity outside of Russia.