News / Health

Online Tool Shows How What You Eat Affects Pollution

Reducing animal protein consumption cuts nitrogen pollution.
Reducing animal protein consumption cuts nitrogen pollution.



Looking to lead a more eco-friendly lifestyle? You could start by cutting back on meat. A new nitrogen footprint calculator shows you the impact your diet has on the environment.  

You may have heard of the concept of a carbon footprint. That's how much of the greenhouse gas carbon dioxide your lifestyle generates. Now researchers have developed a way to measure how our lifestyle - and in particular our diets - impacts another major source of climate-changing pollution: nitrogen.

Everything needs nitrogen, from plants to plankton to people. It's a key element in the proteins that make up our bodies.

Good news, bad news

In the early twentieth century, scientists figured out a way to take nitrogen out of the air and turn it into a form that plants could use. The invention of synthetic nitrogen fertilizer dramatically improved food production.

"That's the good news," says environmental sciences professor Jim Galloway at the University of Virginia. "We're able to feed the world's population because of this wonderful invention."

The bad news, Galloway says, is that many parts of the world use far too much nitrogen fertilizer. Burning fossil fuels also creates nitrogen pollution. Galloway says the excess nitrogen "contributes to smog, acid rain, loss of biodiversity, dead zones along the coast, global warming, stratospheric ozone depletion. The list is quite long."

Visualizing impacts

Galloway and his colleagues developed the nitrogen footprint calculator to show how people's behaviors contribute to that long list of environmental impacts.

The calculator starts with a graph showing the amount of nitrogen pollution produced by the average person. One of the first things you notice is that food is far and away the biggest contributor: 72 percent of the 42 kilograms the average American produces comes from food consumption. Housing, transportation and goods and services make up the rest.

To see exactly how your diet affects your nitrogen footprint, the calculator lets you adjust how many times a week you eat 16 different kinds of foods.

"As you change your consumption, you can see how the graph changes," says co-creator Allison Leach at the University of Virginia. "So as you scale down one bar, you can see your nitrogen footprint shrinking."

Too much protein

Americans eat far more protein on average than the U.S. Department of Agriculture recommends, Leach says. "Reducing your protein to the recommended levels is going to have a huge impact on reducing your nitrogen footprint. [That] reduces it by almost half."

Reducing the amount of animal protein is one of the quickest ways to shrink that footprint. Galloway says that's because feeding plants to animals is an inefficient use of nitrogen.

"For large animals like beef, a very large fraction of the nitrogen that enters the cow's mouth is excreted out the back end," he says.

Beef is less efficient than chicken or pork, while plant sources like legumes are the most efficient, Leach says.

Nitrogen footprints around the world

She and her colleagues also created nitrogen footprint calculators for Germany and the Netherlands. She says their footprints are smaller largely because they tend to eat less meat, not because of major differences in their farming practices.

"Industrialized agriculture production is pretty consistent among developed countries. But it's going to be very different in developing countries."

The next step, Leach says, is a nitrogen footprint calculator for India, a developing country where farming practices are very different from in the industrialized world.

Footprints growing

But even in the developing world, nitrogen footprints are changing. The world's population is not only growing, it's also growing richer. One consequence is that people are eating more animal protein. Galloway says they have looked at what the world might look like in 2050 - and it raises concerns.

"If the entire world had the per capita resource-use habits that people in North America have, then we would be putting three to four to five times more reactive nitrogen into the environment than we are now," he says. "And that's frankly untenable. Our ecosystems can't handle that."

Galloway says that’s why it’s so important that we all do a better job managing the amount of nitrogen we put on our fields, in our mouths, and into our environment.

You May Like

US, China Have Dueling Definitions of Cybersecurity

Analysts say attribution or or proving that a particular individual or government is responsible for a hack, is a daunting task More

Snowden: I'd Go to Prison to Return to US

Former NSA contractor says he has not received a formal plea-deal offer from US officials, who consider him to be a traitor More

Goodbye Pocahontas: Photos Reveal Today's Real Native Americans

Weary of stereotypes, photographer Matika Wilbur is determined to reshape the public's perception of her people More

This forum has been closed.
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Russia’s Syria Involvement Raising Concerns in Europei
Luis Ramirez
October 02, 2015 4:45 PM
European nations are joining the United States in demanding that Russia stop targeting opposition groups other than the Islamic State militants as Russian warplanes continue to conduct raids in Syria. The demand came in a statement from Britain, France, Germany, Qatar, Saudi Arabia, Turkey and the United States Friday. VOA Europe correspondent Luis Ramirez reports.

Video Russia’s Syria Involvement Raising Concerns in Europe

European nations are joining the United States in demanding that Russia stop targeting opposition groups other than the Islamic State militants as Russian warplanes continue to conduct raids in Syria. The demand came in a statement from Britain, France, Germany, Qatar, Saudi Arabia, Turkey and the United States Friday. VOA Europe correspondent Luis Ramirez reports.

Video First Self-Driving Truck Debuts on European Highways

The first automated semi-trailer truck started its maiden voyage Friday, Oct. 2, on a European highway. The Daimler truck called 'Actros' is the first potentially mass-produced truck whose driver will be required only to monitor the situation, similar to the role of an airline captain while the plane is in autopilot mode. VOA’s George Putic reports.

Video Nano-tech Filter Cleans Dirty Water

Access to clean water is a problem for hundreds of millions of people around the world. Now, a scientist and chemical engineer in Tanzania (in East Africa) is working to change that by creating an innovative water filter that makes dirty water safe. VOA’s Deborah Block has the story.

Video Demand Rising for Organic Produce in Cambodia

In Cambodia, where rice has long been the main cash crop, farmers are being encouraged to turn to vegetables to satisfy the growing demand for locally produced organic farm products. Daniel de Carteret has more from Phnom Penh.

Video Migrant Influx Costs Europe, But Economy Could Benefit

The influx of hundreds of thousands of refugees and migrants is testing Europe’s ability to respond – especially in the poorer Balkan states. But some analysts argue that Europe will benefit by welcoming the huge numbers of young people – many of them well educated and willing to work. Henry Ridgwell reports from London.

Video Botanists Grow Furniture, with Pruning Shears

For something a bit out of the ordinary to furnish your home, why not consider wooden chairs, crafted by nature, with a little help from some British botanists with an eye for design. VOA’s Jessica Berman reports.

Video New Fabric Helps Fight Dust-Related Allergies

Many people around the world suffer from dust-related allergies, caused mainly by tiny mites that live in bed linen. Polish scientists report they have successfully tested a fabric that is impenetrable to the microscopic creatures. VOA’s George Putic has more.

Video Burkina Faso's Economy Deeply Affected by Political Turmoil

Political turmoil in Burkina Faso over the past year has taken a toll on the economy. The transitional government is reporting nearly $70 million in losses in the ten days that followed a short-lived coup by members of the presidential guard earlier this month. The crisis shut businesses and workers went on strike. With elections on the horizon, Emilie Iob reports on what a return to political stability can do for the country's economic recovery.

Video Fleeing Violence, Some Syrians Find Refuge in Irbil

As Syrians continue to flee their country’s unrest to seek new lives in safer places, VOA Persian Service reporter Shepol Abbassi visited Irbil, where a number Syrians have taken refuge. During the religious holidy of Eid al-Adha, the city largely shut down, as temperatures soared. Amy Katz narrates his report.

Video Nigeria’s Wecyclers Work for Reusable Future in Lagos

The streets and lagoons of Africa's largest city - Lagos, Nigeria - are often clogged with trash, almost none of which gets recycled. One company is trying to change that. Chris Stein reports for VOA from Lagos.

Video Sketch Artist Helps Catch Criminals, Gives a Face to Deceased

Police often face the problem of trying to find a crime suspect based on general descriptions that could fit hundreds of people in the vicinity of the crime. In these cases, an artist can use information from witnesses to sketch a likeness that police can show the public via newspapers and television. But, as VOA’s Greg Flakus reports from Houston, such sketches can also help bring back faces of the dead.

Video Thailand Set to Build China-like Internet Firewall

Thai authorities are planning to tighten control over the Internet, creating a single international access point so they can better monitor content. VOA Correspondent Steve Herman reports from Bangkok on what is being called Thailand’s own "Great Firewall."

Video Croatian Town’s War History Evokes Empathy for Migrants

As thousands of Afghanistan, Iraqi and Syrian migrants pass through Croatia, locals are reminded of their own experiences with war and refugees in the 1990s. VOA's Daniel Schearf reports from the town of Vukovar, where wartime scars still are visible today.

Video Long Drought Affecting California’s Sequoias

California is suffering under a historic four-year drought and scientists say even the state's famed sequoia trees are feeling the pain. The National Park Service has started detailed research to see how it can help the oldest living things on earth survive. VOA’s George Putic reports.

VOA Blogs