Excessive Reactive Nitrogen in Environment Alarms Environmental Scientists



“… and due to the interactions of nitrogen and 

carbon, makes the challenge of providing food and 

energy to the world’s peoples without harming the 

global environment a tremendous challenge,”….



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Excessive Reactive Nitrogen in Environment Alarms Environmental Scientists


ScienceDaily (May 18, 2008) – While human-caused 

global climate change has long been a concern for 

environmental scientists and is a well-known 

public policy issue, the problem of excessive 

reactive nitrogen in the environment is 

little-known beyond a growing circle of 

environmental scientists who study how the 

element cycles through the environment and 

negatively alters local and global ecosystems and 

potentially harms human health.


Two new papers by leading environmental 

scientists bring the problem to the forefront in 

the May 16 issue of the journal Science. The 

researchers discuss how food and energy 

production are causing reactive nitrogen to 

accumulate in soil, water, the atmosphere and 

coastal oceanic waters, contributing to the 

greenhouse effect, smog, haze, acid rain, coastal 

“dead zones” and stratospheric ozone depletion.


“The public does not yet know much about 

nitrogen, but in many ways it is as big an issue 

as carbon, and due to the interactions of 

nitrogen and carbon, makes the challenge of 

providing food and energy to the world’s peoples 

without harming the global environment a 

tremendous challenge,” said University of 

Virginia environmental sciences professor James 

Galloway, the lead author of one of the Science 

papers and a co-author on the other. “We are 

accumulating reactive nitrogen in the environment 

at alarming rates, and this may prove to be as 

serious as putting carbon dioxide in the 



Galloway, the founding chair of the International 

Nitrogen Initiative, and a co-winner of the 2008 

Tyler Prize for environmental science, is a 

longtime contributor to the growing understanding 

of how nitrogen cycles endlessly through the 

environment. In numerous studies over the years 

he has come to the realization of the “nitrogen 



In its inert form, nitrogen is harmless and 

abundant, making up 78 percent of the Earth’s 

atmosphere. But in the past century, with the 

mass production of nitrogen-based fertilizers and 

the large-scale burning of fossil fuels, massive 

amounts of reactive nitrogen compounds, such as 

ammonia, have entered the environment.


“A unique and troublesome aspect of nitrogen is 

that a single atom released to the environment 

can cause a cascading sequence of events, 

resulting ultimately in harm to the natural 

balance of our ecosystems and to our very 

health,” Galloway said.


A nitrogen atom that starts out as part of a 

smog-forming compound may be deposited in lakes 

and forests as nitric acid, which can kill fish 

and insects. Carried out to the coast, the same 

nitrogen atom may contribute to red tides and 

dead zones. Finally, the nitrogen will be put 

back into the atmosphere as part of the 

greenhouse gas nitrous oxide, which destroys 

atmospheric ozone.


Galloway and his colleagues suggest possible 

approaches to minimizing nitrogen use, such as 

optimizing its uptake by plants and animals, 

recovering and reusing nitrogen from manure and 

sewage, and decreasing nitrogen emissions from 

fossil fuel combustion.


“Nitrogen is needed to grow food,” Galloway says, 

“but because of the inefficiencies of nitrogen 

uptake by plants and animals, only about 10 to 15 

percent of reactive nitrogen ever enters a human 

mouth as food. The rest is lost to the 

environment and injected into the atmosphere by 



“We must soon begin to manage nitrogen use in an 

integrated manner by decreasing our rate of 

creation of reactive nitrogen while continuing to 

produce enough food and energy to sustain a 

growing world population.”


Galloway’s next effort is to create a “nitrogen 

footprint” calculator that people can access on 

the Internet, very similar to current “carbon 

footprint” calculators.


He says people can reduce their nitrogen 

footprints by reducing energy consumption at 

home, traveling less, and changing diet to 

locally grown vegetables (preferably organic) and 

fish and consuming less meat.


Galloway is quick to point out that along with 

the problems of excess reactive nitrogen in many 

areas of the world, there also are large regions, 

such as Africa, with too little nitrogen to grow 

enough food for rapidly growing populations. In 

those regions, the challenge is find ways to 

increase the availability of nitrogen while 

minimizing the negative environmental effects of 

too much nitrogen.


Adapted from materials provided by University of Virginia. (2008, May 18).




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