Behind this harsh reality, we must also add the very costly bill for the production of fertilisers used by these two industries.
The greenhouse gas emissions they generate can be compared to those produced by plastics (4%), cement (5%) or metallurgy (7%).
The total amounts to some 2.6 billion tons of CO2 equivalent, or about 5% of annual global emissions, according to a study published in early February in Nature Food.
The work of researchers from the University of Cambridge has determined that what impacts the planet the most is not so much the production of these fertilisers – which still represents a third of the emissions related to fertilisers – but rather their use in the fields (two thirds).
The problem? The production of nitrous oxide generated by the bacteria that ingest the fertiliser. This is one of the most potent greenhouse gases.
In order to grow, plants need a few basic things: nutrients, nitrogen, phosphorus and potassium. Components found in a liquid that humans all over the world produce: namely urine.
In fact, ancient Romans are believed to have used urine as a fertiliser in their gardening. And today brands such as French company Gerbeaud recommend it for amateur gardeners to grow vegetables, under certain conditions.
According to research conducted by Inrae alongside farmers in the Paris region between 2017 and 2019, urine has been proven to be as effective as chemical fertilisers.
Promoting urine as a fertiliser of the future
Since the 1990s, the idea of reintroducing urine into the agricultural system in order to reduce not only the cost of fertilisers, but also their energy consumption, has been gaining ground.
Until now, most of the research has taken the form of experiments carried out to demonstrate the value of urine as a fertiliser, while combating preconceptions about as well as the disgust that abounds on the subject.
But last autumn a further step was taken in France when the start-up Toopi Organics obtained the green light from Anses, a health safety watchdog in the country, to market a new product: a bio-stimulant made from human urine.
Developed by the Gironde-based company, the recipe is based on urine collected from several locations including music festivals as well as high school and college toilets.
More than just a fertiliser, urine is used “as a culture medium for microorganisms” that improve the ability of plants to absorb nutrients naturally present in the environment, founder Mickaël Roes explained to the press.
The company expects to have collected 3.75 million litres of urine by 2027 through about 20 sites in France.
Toopi Organics’ patented process has also been commercialised in Portugal, Belgium, Italy, Greece and Spain, which could make urine a genuine solution for the future of agriculture in Europe.
Meanwhile in the French city of Lyon, a former assistant at a local wastewater treatment plant has launched a project to collect urine’s most valuable elements: nitrogen and phosphorus.
His start-up, called Les Fertilisateurs, plans to extract these chemical elements from the liquid and turn it into agricultural fertiliser.