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Science Friday
FOR KIDS: Greener Diet
The planet is getting warmer, and what we eat isn’t helping
Web edition : Monday, February 23rd, 2009
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By the time a hamburger finally lands on a dinner plate, it has taken a heavy toll on the environment. According to Swedish scientist Ulf Sonesson, the process of making a one half-pound all-beef burger adds the equivalent (made up of other greenhouse gases) of about 19 times that hamburger’s weight in carbon dioxide.PhotoDisc

Think about what you had for lunch: Was it a hamburger? A chicken sandwich? Barbecue? What about vegetables? Would it surprise you to learn that what you eat can affect the whole planet?

It can — in a big way. Last week, scientists attending the American Association for the Advancement of Science meeting in Chicago presented new studies showing how food and its production affect the globe and its warming climate. The researchers had some bad news for meat-eaters (which is good news for cows!). They also offered some suggestions for how to eat in a more environmentally friendly way.

You’ve probably heard of global warming: For many years, scientists have warned that our planet is getting warmer. If current trends continue, then animals may start to die off and life could get very difficult for everyone. The temperature is on the rise because for more than a century, human kind has been releasing massive amounts of gases into the atmosphere, called “greenhouse gases.” These gases surround the planet and keep heat from escaping the atmosphere. You can think of them as a blanket for the Earth that traps heat. One of these greenhouse gases is carbon dioxide.

What does this have to do with food? A big chunk of the carbon dioxide that we put in the atmosphere every year comes from the process of making and eating food, the scientists reported in Chicago. The production of meat contributes a lot of that carbon dioxide. And much of meat’s contribution comes from beef, which is responsible for releasing even more warming gases into the atmosphere.

The process of making a hamburger, for example, requires a lot of energy. A cow has to be fed and raised on farmland, and cow manure is a major source of methane — an especially potent greenhouse gas. The cow has to be slaughtered. The meat has to be processed and shipped to a consumer, which takes fuel. Most of the cow won’t even be used for meat that people eat.

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To grow and eat a pound of potatoes sends less than one quarter-pound of carbon dioxide or equivalent warming gases into the air.Scott Bauer/USDA-ARS

By the time a hamburger finally lands on a dinner plate, it has taken a heavy toll on the environment. According to Ulf Sonesson of the Swedish Institute for Food and Biotechnology in Goteborg, Sweden, the process of making a one half-pound all-beef burger adds the equivalent (made up of other greenhouse gases) of about 19 times that hamburger’s weight in carbon dioxide.

The message from the research is clear: We can drastically reduce the production of global-warming gases by eating less beef. (That’s healthier, too, since Americans eat twice as much beef as is advised by the U.S. Department of Agriculture.) Other kinds of meat like pork and chicken do less harm to the environment — at least in terms of the amount of greenhouse gases released. Nathan Pelletier, a scientist Dalhousie University in Canada, reported that if everyone in industrial countries (like the United States) substituted chicken for beef, we would cut meat’s contribution in these countries to the greenhouse warming of Earth’s air by more than half.

All kinds of meat, the scientists reported, are harder on the planet than vegetables. To grow and eat a pound of potatoes, for example, sends less than one quarter-pound of carbon dioxide or equivalent warming gases into the air. So shifting our diet to less meat and more vegetables, as it turns out, may do the world some good.

Power Words:

greenhouse gas: Chemical compounds found in the Earth’s atmosphere that allow sunlight to enter the atmosphere freely. When sunlight strikes the Earth’s surface, some of it is re-radiated back towards space as heat. Greenhouse gases absorb this infrared radiation and trap the heat in the atmosphere.

carbon dioxide: A colorless, odorless, incombustible gas made up of one carbon and two oxygen atoms.

methane: An odorless, colorless, flammable gas that is the major constituent of natural gas.

atmosphere: The gaseous mass or envelope surrounding a celestial body, especially the one surrounding the earth, and retained by the celestial body's gravitational field.


Found in: Agriculture, Climate Change, Environment, Food Science, Science & Society and Science News For Kids
Comments 4
  • "If current trends continue, then animals may start to die off and life could get very difficult for everyone." These sorts of scare tactics directed at youth and based on a politically motivated agenda with debatable science continues to be very disappointing coming from Science News! At the very least you have an ethical obligation to point out that many highly qualified scientists do not believe that human caused emissions of GHGs is impacting climate to a significant extent. Using these sorts of distortions and scare tactics and directing this at youth suggests that you are no longer interested in reporting science but are in fact part of the political agenda. I continue to be disappointed in Science News on this issue and will not renew my subscription for this reason after over 30 years.
    David Gossman David Gossman
    Feb. 24, 2009 at 11:50am
  • Trying to reduce one's ecological and carbon footprint is immensely worthwhile and necessary, even without climate change considerations. Even 'traditional' deniers and paid lobbyists have stopped trying to create doubts (similar to what the tobacco industry did before) on the anthropogenic origins of the current climate change. They have now moved on to bargaining on how much they can afford to change, by citing economics, and pointing fingers at China and India. Unfortunately, some people are still hanging on to the old myths. I am happy that Science News is running an article on this important topic for kids. But competing against the slick "education materials" produced by the meat and dairy industry is not going to be easy. Perhaps it's the job of each parent to seek out the truth on this matter.
    Alcyon Alcyon
    Mar. 2, 2009 at 11:17pm
  • Who are these "highly qualified scientists"? Do any of them have a climate model of any kind? If a verifiable (i.e. one that runs backwards as well as forwards for example http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf ) climate model could be made that shows that raising CO2 levels almost 40% isn't "impacting climate to a significant extent" it would be on the front page of every major newspaper. By the way where were these "scientists" on smoking cause’s cancer, acid rain, the ozone hole, and that fish need water (including those of the Klamath River Basin)?
    http://www.waronscience.com/excerpt.php?p=4
    http://www.guardian.co.uk/environment/2008/may/13/carbonemissions.climatechange
    inveganatheist inveganatheist
    Mar. 11, 2009 at 1:00am
  • This article raises such an important issue: Eating less beef can really help reduce greenhouse gas emissions. The message is not "eliminate meat," it's: "reduce the amount of beef you eat." It's a simple choice we're empowered to make with each meal!
    Tamar  Hurwitz Tamar Hurwitz
    Jun. 30, 2009 at 8:37pm
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