With Earth Day on the horizon and April's designation as Earth Month, the next few weeks marks the time when people are thinking about their own roles in helping the environment. The good news is there are options that don't involve chaining yourself to a sequoia; it can be as simple as taking a look at what's on your plate.

When people think of "green" foods, their first inclination may be to reach for that head of broccoli in their vegetable crisper, and they wouldn't be wrong in doing so. That's because vegetables outrank their meat counterparts in terms of their environmental impact.

Food's environmental impact lies in measuring in its carbon footprint -- the amount of greenhouse gases involved in the process, from growing the food to how it ends up on your plate. And while the easiest culprit to spot is the exhaust coming from cars and trucks, there are plenty of other polluting perpetrators, like the energy it takes to process and manufacture the food.

Below is a list of the top 10 food offenders in terms of the carbon footprint they leave behind. Story continues below:

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• Number 10: Potatoes

  At 2.9 kg of greenhouse gases produced for ever kg eaten, potatoes are the most environmentally unfriendly vegetable out there. The bulk of its gases aren't in the production, though -- it's what happens to potatoes after they leave the farm (cooking, processing, travelling and waste disposal) that rack up emissions. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 9: Eggs

  For every kilogram of eggs consumed, 4.8 kg of greenhouse gases are produced. If that doesn't seem too bad, try factoring in the notion that Canada alone produces about 6 billion eggs a year. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 8: Canned Tuna

  With 6.1 kg of greenhouse gases produced for every kg of canned tuna, this item makes the list because two-thirds of its carbon footprint comes from product emissions. This means that the bulk of the gases created by canned tuna come from raising the fish and not the actual canning process. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 7: Chicken

  From McNuggets to a cordon bleu, chicken in all of its parts make up roughly one-third of the world's meat intake. Coupled with 6.9 kg of greenhouse gases for every kg of chicken consumed, and this bird's impact on the environment starts adding up. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 6: Turkey

  Sure it's great for holiday meals, but it might be harder to give thanks this Thanksgiving after learning that one kilogram of turkey contributes to 10.9 kg of greenhouse gases. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 5: Farmed Salmon

  Fans of seafood are in a tough position. Eating wild salmon is frowned upon due to overfishing, but farmed salmon, which is designed to help wild salmon repopulate, comes with a carbon footprint of 11.9kg /kg of salmon. <a href="http://www.flickr.com/photos/havbrukssenter/" target="_hplink">(Photo courtesy of Norsk Havbrukssenter)</a> -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 4: Pork

  It's the <a href="http://www.fao.org/ag/againfo/themes/en/meat/backgr_sources.html" target="_hplink">most popular type of meat consumed by the world</a>, according to the United Nations. But with 36 per cent of the world's population pigging out on pork, its impact on the environment is tough to dismiss -- especially when you factor in pork's carbon footprint of 12.1 kg of gas/ kilogram. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 3: Cheese

  It may surprise you that the third highest producer of greenhouse gases isn't an animal or vegetable, it's cheese. But remember, cheese is something made, not grown or raised and because of that, cheese's carbon footprint works out to 13.5 kg/ kg consumed. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 2: Beef

  With 27 kg of carbon dioxide and methane produced for every kilogram eaten, beef would be the runner up if there ever was a largest carbon footprint pageant. Its poor environmental friendliness is due mostly to the large amount of energy it takes to feed, milk and butcher cattle. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

• Number 1: Lamb

  Lambs are cute. The 39.2 kg of greenhouse gases it takes to eat one kilogram? Not as cute. On the bright side, since lamb isn't consumed in as high volumes as pork, beef or poultry, the overall contribution to global warming is lessened. -<a href="http://www.ewg.org/meateatersguide/a-meat-eaters-guide-to-climate-change-health-what-you-eat-matters/climate-and-environmental-impacts/" target="_hplink">statistics via Environmental Working Group</a>

TEXT VERSION OF SLIDESHOW HERE

In the past, environmentalists have cited "food miles" as the unit by which to measure a food's impact on the environment. Their argument was the further a piece of food travelled, the more its harm to the environment. But the concept has come under scrutiny, with others nothing it's how the food is made, not how far it travels that contributes to its carbon footprint.

"The concept of food miles is unhelpful and stupid. It doesn't inform about anything except the distance travelled," said Dr Adrian Williams, of the National Resources Management Centre at Cranfield University in an interview with The Observer.

The story is very much the same in Canada, according to the David Suzuki Foundation, with an average of 11 per cent of a food's carbon footprint coming from travel and 83 per cent of the food coming from how the food is grown.

Another offender of greenhouse gases, according to the Foundation, lies in people's palate for meat. Roughly one-fifth of the total greenhouse gases produced comes from livestock production, which isn't surprising, considering 70 per cent of all agricultural land use is devoted to livestock production and makes up for 30 per cent of the land surface of the planet.

SLIDESHOW TEXT VERSION:

• 10. Potatoes: At 2.9 kg of greenhouse gases produced for ever kg eaten, potatoes are the most environmentally unfriendly vegetable out there.
• 9. Eggs: For every kilogram of eggs consumed, 4.8 kg of greenhouse gases are produced.
• 8. Canned Tuna: With 6.1 kg of greenhouse gases produced for every kg of canned tuna, this item makes the list because two-thirds of its carbon footprint comes from product emissions.
• 7. Chicken: From McNuggets to a cordon bleu, chicken in all of its parts make up roughly one-third of the world's meat intake.
• 6. Turkey: Sure it's great for holiday meals, but it might be harder to give thanks this Thanksgiving after learning that one kilogram of turkey contributes to 10.9 kg of greenhouse gases.
• 5. Farmed Salmon: Fans of seafood are in a tough position. Eating wild salmon is frowned upon due to overfishing, but farmed salmon, which is designed to help wild salmon repopulate, comes with a carbon footprint of 11.9kg /kg of salmon.
• 4. Pork: It's the most popular type of meat consumed by the world, according to the United Nations.
• 3. Cheese: It may surprise you that the third highest producer of greenhouse gases isn't an animal or vegetable, it's cheese.
• 2. Beef: With 27 kg of carbon dioxide and methane produced for every kilogram eaten, beef would be the runner up if there ever was a largest carbon footprint pageant.
• 1. Lamb: Lambs are cute. The 39.2 kg of greenhouse gases it takes to eat one kilogram? Not as cute.

EDITOR'S NOTE: Please note, the sourcing information for the statistics in the slideshow above has been updated. It previously referenced The 9 Billion, a site quoting the primary source, the Environmental Working Group.