By Matt McGrath
The United Nations Environment Programme (Unep) has issued a warning
about the dangers posed by nitrous oxide, the so-called “laughing
gas”.
In a report presented at global climate talks, Unep says the chemical
is now the biggest threat to the ozone layer.
It says that thanks to farming and human activities, levels of the gas
could double by 2050.
If this happens, it could reverse gains made to slow the thinning of
the ozone layer and exacerbate global warming.
Nitrous oxide is one of several greenhouse agents which are dubbed
“Cinderella’ gases, because their contribution passes unnoticed.
N2O exists naturally in the atmosphere but agriculture is by far the
biggest human source, producing two-thirds of emissions.
It is also used in dentistry and surgery as an anaesthetic and a
painkiller. It is sometimes used as a recreational drug, called
“nozz”, and its abuse has been linked to permanent neurological damage
and deaths.
Now, researchers say that it has emerged as the single biggest threat
to the ozone layer since chlorofluorocarbons and other damaging gases
were restricted by the Montreal Protocol signed in 1987.
The famous “hole” over Antarctica has started to recover as a result
of the phasing out of the hair sprays and refrigerants that contained
these substances.
But according to this new report, if no action is taken, levels of
nitrous oxide could increase by 83% from 2005 to 2050.
“The continued build-up of N2O in the atmosphere will continue to
deplete the stratospheric ozone layer and in so doing will to a degree
undermine the achievements of the Montreal Protocol,” says the
document.
Unep’s executive director, Achim Steiner, warned that as well as
posing a threat to the ozone layer, nitrous oxide has a powerful
global warming effect.
“It’s one of those elements in our modern life that we have not fully
understood in terms of its negative impacts.
“If we can bring it to the attention of farmers, government and
industry, the importance of managing nitrous oxide more efficiently,
and the climate benefits – it is a no-regret option,” he said.
The research underlines the fact that nitrous oxide is the world’s
third most powerful gas when it comes to global warming potential.
Dr Joseph Alcamo is Unep’s chief scientist. He told a news conference
here in Warsaw that the gas could not be ignored any longer.
“Nitrous oxide makes up only 6% of the greenhouse gases but in terms
of CO2, it is the equivalent to emitting three [billion tonnes] a
year.
“This is about 50% of the total amount of emissions from every vehicle
in the world.”
However, the researchers were optimistic that both the warming
potential and the danger to the ozone layer could be swiftly curtailed
if action was taken, particularly in agriculture.
“In the agricultural sector, it comes down to using nitrogen
fertiliser more efficiently, a very simple idea, to improve the uptake
by crops and livestock,” said Dr Alcamo.
“It has a lot to do with using the right fertiliser, in the right
place.” – BBC Environment
