Weaponised bugs: War on climate change

Nicolas Denieul plants his spade in the ground and turns over a clod of soil to reveal a mass of earthworms seething around plant roots — fat ones and thin ones, delicate translucent violet and dark brown.

“That is magnificent. Ten years ago, I never thought I’d see anything like that!” said Denieul, a cheerful French farmer, his hands full of earth in the biting wind. For 10 years ago, there were no worms roaming about his land, near the western city of Le Mans, where he grows wheat, corn and rapeseed to feed the 350 pigs he and his brothers keep. Back then his spade met smooth earth, empty of worms, insects and the other small organisms that signify a healthy soil.

Like forests and oceans, soils also capture carbon, through the vegetable matter that decomposes in them. Instead of being released in the form of gases that contribute to global warming, carbon stocked in soil nourishes plants.

An increase of 0.4 percent a year in the level of carbon in soils would make it possible to stop the current growth of carbon dioxide — a major greenhouse gas — in the atmosphere, according to the French National Institute for Agricultural Research (Inra).

France’s agriculture ministry launched an international research programme on the subject this year, which 40 countries signed up to at the ongoing UN climate talks in Paris.

End of ploughing

On top of urbanisation and deforestation, soils around the world have suffered as a result of the intensification of farming since World War II. “We have massacred the soil” with bigger combine harvesters, deeper ploughing and chemical fertilisers and pesticides,” Mr Denieul said.