Nitrous oxide emissions pose an increasing climate threat

Date:
October 7, 2020
Source:
University of East Anglia
Summary:
Rising nitrous oxide (N2O) emissions are jeopardizing the climate
goals of the Paris Agreement, according to a major new study. The
growing use of nitrogen fertilizers in the production of food
worldwide is increasing atmospheric concentrations of N2O - a
greenhouse gas 300 times more potent than carbon dioxide (CO2)
that remains in the atmosphere for more than 100 years.



FULL STORY ========================================================================== Rising nitrous oxide (N2O) emissions are jeopardizing the climate goals
of the Paris Agreement, according to a major new study by an international
team of scientists.


==========================================================================
The growing use of nitrogen fertilizers in the production of food
worldwide is increasing atmospheric concentrations of N2O -- a greenhouse
gas 300 times more potent than carbon dioxide (CO2) that remains in the atmosphere for more than 100 years.

Published today in the journal Nature, the study was led Auburn
University, in the US, and involved scientists from 48 research
institutions in 14 countries - - including the University of East Anglia
(UEA) in the UK -- under the umbrella of the Global Carbon Project and
the International Nitrogen Initiative.

The aim was to produce the most comprehensive assessment to date of
all global sources and sinks of N2O. Their findings show N2O emissions
are increasing faster than any emission scenario developed by the Intergovernmental Panel on Climate Change (IPCC), consistent with
greenhouse gas scenarios that lead to global mean temperature increases
well above 3DEGC from pre-industrial levels.

The Paris Agreement aims to limit warming to less than 2DEGC but ideally
no more than 1.5DEGC.

The study points to an alarming trend affecting climate change: N2O has
risen 20 per cent from pre-industrial levels -- from 270 parts per billion (ppb) in 1750 to 331ppb in 2018 -- with the fastest growth observed in
the last 50 years due to emissions from human activities.

Prof Hanqin Tian, director of the International Center for Climate and
Global Change Research at Auburn University's School of Forestry and
Wildlife Sciences, co-led the study.



==========================================================================
"The dominant driver of the increase in atmospheric nitrous oxide
comes from agriculture, and the growing demand for food and feed for
animals will further increase global nitrous oxide emissions," said Prof
Tian. "There is a conflict between the way we are feeding people and stabilizing the climate." Like CO2, N2O is a long-lived greenhouse gas
and is also currently the most significant human-induced agent depleting
the stratospheric ozone layer, which protects Earth from most of the Sun's harmful ultraviolet radiation Lead UK author Dr Parvadha Suntharalingam,
of UEA's School of Environmental Sciences, said: "This study presents
the most comprehensive and detailed picture to date, of N2O emissions
and their impact on climate.

"This new analysis identifies the factors driving the steadily increasing atmospheric levels of N2O, and highlights the urgent need to develop
effective mitigation strategies if we are to limit global warming and
meet climate goals." The study presents a comprehensive global N2O
inventory that incorporates both natural and human-related sources, and accounts for the interaction between nitrogen additions to the earth
system and the biochemical processes that control N2O emissions. It
covers 21 natural and human-related sectors between 1980 and 2016.



========================================================================== Human-induced emissions, which are dominated by nitrogen additions to croplands, increased by 30 per cent over the past four decades to 7.3
teragrams of nitrogen per year.

The analysis also reveals an emerging N2O-climate 'feedback' resulting
from interactions between nitrogen additions to crops for food production
and global warming, further enhancing emissions derived from agriculture.

The study found that the largest contributors to global N2O emissions
come from East Asia, South Asia, Africa and South America. Emissions
from synthetic fertilizers dominate releases in China, India and the US,
while emissions from the application of livestock manure as fertilizer dominates releases in Africa and South America. The highest growth rates
in emissions are in emerging economies, particularly Brazil, China and
India, where crop production and livestock numbers have increased.

However, N2O emissions in Europe decreased in agriculture and the chemical industry. This was due to a combination of factors, including voluntary measures to remove N2O from flue gases in the Nylon industry and the introduction of an emissions trading scheme, as well as agriculture in
many Western European countries moving to more efficient use of fertilizer
to reduce environmental impacts such as pollution of groundwater and
surface water.

Policies on nitrogen fertilizer usage were also introduced.

Study co-leader Dr Josep 'Pep' Canadell, of the Commonwealth Scientific
and Industrial Research Organisation (CSIRO) in Australia, is executive director of the Global Carbon Project. He said: "This new analysis
calls for a full-scale rethink in the ways we use and abuse nitrogen fertilizers globally and urges us to adopt more sustainable practices
in the way we produce food, including the reduction of food waste.

"These findings underscore the urgency and opportunities to mitigate
nitrous oxide emissions worldwide to avoid the worst of climate impacts."

========================================================================== Story Source: Materials provided by University_of_East_Anglia. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Hanqin Tian, Rongting Xu, Josep G. Canadell, Rona L. Thompson,
Wilfried
Winiwarter, Parvadha Suntharalingam, Eric A. Davidson, Philippe
Ciais, Robert B. Jackson, Greet Janssens-Maenhout, Michael
J. Prather, Pierre Regnier, Naiqing Pan, Shufen Pan, Glen P. Peters,
Hao Shi, Francesco N.

Tubiello, So"nke Zaehle, Feng Zhou, Almut Arneth, Gianna
Battaglia, Sarah Berthet, Laurent Bopp, Alexander F. Bouwman,
Erik T. Buitenhuis, Jinfeng Chang, Martyn P. Chipperfield, Shree
R. S. Dangal, Edward Dlugokencky, James W. Elkins, Bradley D. Eyre,
Bojie Fu, Bradley Hall, Akihiko Ito, Fortunat Joos, Paul B. Krummel,
Angela Landolfi, Goulven G. Laruelle, Ronny Lauerwald, Wei Li,
Sebastian Lienert, Taylor Maavara, Michael MacLeod, Dylan B. Millet,
Stefan Olin, Prabir K. Patra, Ronald G. Prinn, Peter A. Raymond,
Daniel J. Ruiz, Guido R. van der Werf, Nicolas Vuichard, Junjie
Wang, Ray F. Weiss, Kelley C. Wells, Chris Wilson, Jia Yang,
Yuanzhi Yao. A comprehensive quantification of global nitrous
oxide sources and sinks. Nature, 2020; 586 (7828): 248 DOI:
10.1038/s41586-020- 2780-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201007123131.htm

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