The Role Of Laughing Gas In Climate Change

Carbon dioxide is essential, but laughing gas can roast us pretty quickly

Illustration of the greenhouse effect (Background image: EPA)

It’s well established that greenhouse gases trap heat and are responsible for the global warming we are seeing today. But despite carbon dioxide winning the popularity contest, there are other types of greenhouse gases — some many times more powerful than carbon dioxide. The focus of this post will be to understand the sources and consequences of nitrous oxide a.k.a. laughing gas.

The reason we talk about carbon dioxide more is because of its dominant concentration in the atmosphere, about two-thirds of all greenhouse gases. And while nitrous oxide is only about 6% of the total, it is nearly 300 times more capable of doing what carbon dioxide can do, i.e., trap heat. So while the good news is that controlling its concentration can give us a good short term handle on global warming, if we don't want to get roasted, that 6% eventually should go down and not up.

This is no laughing matter!

But first, where does nitrous oxide (N2O) come from?

Nitrous oxide is a by-product of many industries, but one deserves a special mention.

Agriculture.

In the USA alone, more than three-fourths of nitrous oxide is a result of agricultural practices. Nitrogen is an important component in plant growth for which fertilizers are added. But whether farmers use synthetic fertilizers like ammonia or organic fertilizers like manure, not all nitrogen in them is taken up by the plants. The remaining, after reacting underground with other chemicals and microbes, ultimately finds its way either into the ground and water bodies or into the air in various forms, one of them being nitrous oxide.

Reckless use of fertilizers is one major cause of the increasing concentration of nitrous oxide in the air.

A simplified nitrogen cycle from agriculture (Image)

While some amount of fertilizer is required to support the gigantic food demand from seven billion people, we are really pushing ourselves into a downward spiral here. With all else equal, fertilizers are increasing global warming, which is resulting in depleting soil quality, which is resulting in more use of fertilizers.

Apart from global warming do we have other reasons to care about nitrous oxide?

Turns out, yes. It is messing up the water system and could lead to an increase in skin cancer.

1. Impact On Household Water Supplies

Increasing runoff of phosphorus and nitrates are resulting in large toxic algae blooms, like the one here in one of the USA’s largest lakes, Lake Erie (Image)

Nitrates that leach into the ground sometimes find their way into the water bodies where they fuel toxic algae growth. This impacts the quality of water we get in our homes. In a 2014 toxic algal bloom incidence in Lake Erie, Ohio had to temporarily cut water supply to half a million homes for three days. Even right now, another 62% of US counties are struggling with toxic bloom problems. In another example, an algal bloom in China left more than 2 million people without water for a week!

In a 2014 toxic algal bloom incidence in Lake Erie, Ohio had to temporarily cut water supply to half a million homes for three days.

2. Impact On The Atmosphere

This gas is impacting our atmosphere not just through global warming but also by reacting with our ozone layer and destroying it; the very layer that protects us from the sun’s harmful UV rays. Remember when an ozone hole started appearing over Australia a few decades back and, is believed, led to an increase in the rate of skin cancer?

The only way out, and to control the concentration of nitrous oxide, is to be more efficient and managed in the use of nitrogen-based fertilizers.

Priya Aggarwal works in cleantech and writes about climate change and the environment. Connect with her on Twitter.

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