The huge emissions from an under-the-radar source

Surprisingly, it’s nitrogen fertilizer – and it affects you!

There’s a good chance you’ve never heard of German chemists Fritz Haber or Carl Bosch – yet they’ve probably changed our world more than anyone else. 

A little over a hundred years ago, they developed the Haber-Bosch process, an industrial procedure that captured nitrogen from the atmosphere and turned it into ammonia – a key ingredient of agricultural fertilizer.  It suddenly enabled a huge increase in global food production, which in turn contributed to an explosion in our human population.  Fritz Haber’s first prototype produced half a cup of ammonia per hour; today, 240 million tonnes of ammonia are produced each year globally.

All good, right?  Except that the Haber-Bosch process uses natural gas – a LOT of it – to the point where:

• The production of one tonne of ammonia results in three tonnes of carbon dioxide emissions
• The Haber-Bosch process generates nearly two per cent of global emissions, more than the annual emissions of Germany.  If Haber-Bosch were a country, it would be the world’s eighth largest emitter.

So what’s the point to all of this?

1. Nitrogen fertilizers are essential to the industrial food production systems we’ve become dependent upon; we’d have a hard time feeding ourselves without them.
2. Yet, they are enormous sources of the emissions that are driving climate change.
3. So we need to use them as wisely and cautiously as possible.
4. Which means we should probably use them as sparingly as possible, for food production only, and not waste them on non-food crops.

Which comes to the real point.  The biggest non-food crop in our country, if not the world, is lawn: watered, mown – and typically fertilized with nitrogen.  Ironically, watering and fertilizing make it grow faster – which means it needs to be mown more often.  (And just to clarify: the extra growth caused by the fertilizer comes nowhere near to offsetting the carbon footprint of the fertilizer – or the gas-powered lawn mower.)

Fortunately, as pointed out in this optimistic and insightful story, our lawns are something each of us has complete control over.  We get to decide.

So this spring, please make this simple resolution: don’t use nitrogen fertilizers on your lawn.  If every Canadian did this simple and easy thing, we’d put a nice dent in emissions.  And we’d probably have more time for summer fun, because we’d be spending less time mowing.

PS How to recognize whether a fertilizer contains nitrogen?

• Look for the words ‘ammonium nitrate’ or ‘urea’, the most common nitrogen fertilizers derived from Haber-Bosch
• Most fertilizers are labelled with three numbers (IE 34-0-0 or 18-45-0) that represent their percentage of nitrogen, phosphorus and potassium respectively.  A high first number means a lot of Haber-Bosch derived nitrogen.  Organic fertilizers with low first numbers are perfectly fine, because their nitrogen comes from natural sources like compost.