Since the ban on CFCs, which devoured stratospheric ozone, nitrous oxide (N 2 O), mass produced by agriculture, has become the main enemy of this protective layer, and is a powerful gas for greenhouse effect. Two studies show the very harmful effects.
After the(CO 2 ) hunt , should we declare war on N 2 O? The , also known as nitrous oxide or laughing gas, is naturally produced (by and oceans). But today one third of the emanations are due to human activities, and in particular to the of manure and nitrogen fertilizers.
Two teams have just demonstrated the danger, both for maintaining a high concentration ofin the , known as the which protects living beings from rays , and for the because nitrous oxide is a powerful , 275 times more efficient than CO 2 .
Akkihebbal Ravishankara and his team from theat the National Oceanic and Atmospheric Administration ( ) have studied the impact of N 2 O on stratospheric ozone, which apparently has not never been done yet. The authors sought to determine the relative importance of nitrous oxide over the effects of other gases known to degrade ozone in the stratosphere.
In 1987, thebanned (or chlorofluorocarbons, widely used in the cold industry or as a ) and other , such as (hydrochlorofluorocarbons) and halogenated . These substances, which degrade stratospheric ozone, have been progressively abandoned by a very large number of countries.
But nitrous oxide was not included in this protocol and, as a result, is now becoming the first enemy of the, Akkihebbal Ravishankara and his colleagues conclude in an article published in Science . According to the authors, it will remain so throughout the twenty-first century.
Nitrogen in the ground is nitrogen in the air and less ozone
Human activities, in fact, emit a lot and more and more. The main source is the spreading of slurry, manure and nitrogen fertilizers. This is the breeding and intensiveagain in the hot seat, after studies showing that the methane produced by cows increases the greenhouse effect …
In Nature Geoscience , Eric Davidson, biogeochemist at theMassachusetts, has counted human productions. According to him, manure and manure release into the 2% of the nitrogen they contain and nitrogen fertilizers 2.5%. In total, he explains, manure, through manure and manure, releases 2.8 million tonnes of N 2 O annually , in addition to the 2.2 million tonnes from synthetic fertilizers.
Far behind, the industry denies 0.8 million tonnes and theof 0.5 million tonnes. Taking into account the evolution of agriculture, Davidson estimated nitrous oxide injection into the atmosphere between 1860 and 2005. The concentration in the atmosphere would have increased from 270 to 319 ppb (parts per billion).
The author notes that as the proportion of animalin the human diet is increasing, manure management will become ” an important component of efforts to reduce human production of nitrous oxide .” Soon a tax N 2 O?