For the first time, this study has evaluated nitrous oxide emissions from human activities in terms of their potential impact on Earth's ozone layer.
As chlorofluorocarbons (CFCs), which have been phased out by international agreement, ebb in the atmosphere, nitrous oxide will remain a significant ozone-destroyer, the study found. Today, nitrous oxide emissions from human activities are more than twice as high as the next leading ozone-depleting gas.
Nitrous oxide is emitted from natural sources and as a byproduct of agricultural fertilization and other industrial processes. Calculating the effect on the ozone layer now and in the future, NOAA researchers found that emissions of nitrous oxide from human activities erode the ozone layer and will continue to do so for many decades.
The study, authored by A.R. Ravishankara, J.S. Daniel and Robert W. Portmann of the NOAA Earth System Research Laboratory (ESRL) chemical sciences division, appears online today in the journal Science. ESRL tracks the thickness of the ozone layer, as well as the burden of ozone-depleting compounds in the atmosphere. It maintains a large portion of the world air sampling and measurement network. NOAA scientists also conduct fundamental studies of the atmosphere and atmospheric processes to improve understanding of ozone depletion and of the potential for recovery the ozone layer.
"The dramatic reduction in CFCs over the last 20 years is an environmental success story. But manmade nitrous oxide is now the elephant in the room among ozone-depleting substances," said Ravishankara, lead author of the study and director of the ESRL Chemical Sciences Division in Boulder, Colo.
The ozone layer serves to shield plants, animals and people from excessive ultraviolet light from the sun. Thinning of the ozone layer allows more ultraviolet light to reach the Earth's surface where it can damage crops and aquatic life and harm human health.
Though the role of nitrous oxide in ozone depletion has been known for several decades, the new study is the first to explicitly calculate that role using the same measures that have been applied to CFCs, halons and other chlorine- and bromine-containing ozone-depleting substances.
With CFCs and certain other ozone-depleting gases coming in check as a result of the 1987 Montreal Protocol, the international treaty that phased out ozone-destroying compounds, manmade nitrous oxide is becoming an increasingly larger fraction of the emissions of ozone-depleting substances. Nitrous oxide is not regulated by the Montreal Protocol.
Nitrous oxide is also a greenhouse gas, so reducing its emission from manmade sources would be good for both the ozone layer and climate, the scientists said.
In addition to soil fertilization, nitrous oxide is emitted from livestock manure, sewage treatment, combustion and certain other industrial processes. Dentists use it as a sedative (so-called "laughing gas"). In nature, bacteria in soil and the oceans break down nitrogen-containing compounds, releasing nitrous oxide. About one-third of global nitrous oxide emissions are from human activities. Nitrous oxide, like CFCs, is stable when emitted at ground level, but breaks down when it reaches the stratosphere to form other gases, called nitrogen oxides, that trigger ozone-destroying reactions.
NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.
Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences