For a lot of people the concern about the environment unfortunately does not also carry over into the foods that they choose to eat. They may think about food miles, but what about the bigger picture of food production.

When it comes to global warming, meat is the Hummer of food, scientists say.

Choosing to eat meat as a part of your diet comes at a huge cost to global emissions and land use. This article takes a look at the carbon dioxide equivalent emissions of beef.

When it comes to global warming, hamburgers are the Hummers of food, scientists say.

Simply switching from steak to salad could cut as much carbon as leaving the car at home for a couple of days each week. That's because beef is such an incredibly inefficient food to produce and cows release so much harmful methane into the atmosphere, said Nathan Pelletier of Dalhousie Universtiy in Canada.

Pelletier is one of a growing number of scientists studying the environmental costs or food from paddock to plate. By looking at everything from how much grass a cow eats before it is ready for slaughter to the emissions released by manure, they are getting an idea of the true costs of food.

The livestock sector is estimated to account for 18 percent of global greenhouse gas emissions and beef is the biggest culprit. Even though beef only accounts for 30 per cent of meat consumption in the developed world, it's responsible for 78 per cent of the emissions, Pelletier said at a meeting of the American Association for the Advancement of Science.

That's because a single kilogram of beef produces 16 kilograms of carbon dioxide equivalent emissions: four times higher than pork and more than ten times as much as a kilogram of poultry, Pelletier said.

If people were simply to switch from beef to chicken, emissions would be cut by 70 per cent, Pelletier said. And if meat consumption in the developed world was cut from about 90 kilograms of meat a year to the recommended level of 53 kilograms a year, livestock related emissions would fall by 44 per cent.