(NewsTarget) The environmental footprint of producing just over two pounds of beef is greater than that of driving a car for three hours, according to a Japanese study reported on "New Scientist."A research team led by Akifumi Ogino of the National Institute of Livestock and Grassland Science in Tsukuba, Japan examined the energy used and greenhouse gases emitted at every step in the process of producing beef, including raising calves, managing animals and producing and transporting feed. The researchers found that it took 169 megajoules of energy to produce 2.2 pounds of beef (the equivalent of four average-sized steaks or nearly nine quarter-pound burgers). This is the same amount of energy that would be consumed by leaving a 100-watt bulb burning for 20 days.One-third of this energy went into producing and transporting the animals' feed.The researchers also found that producing 2.2 pounds of beef resulted in greenhouse gas emissions equivalent to 80.25 pounds of carbon dioxide, the same amount that would be emitted by driving a car for 155 miles at 50 miles an hour. Most of these emissions came in the form of methane released from the cows' digestive systems.The true ecological impact of beef is significantly higher than the numbers given by the study, however, because the researchers did not look at the energy used or emissions involved in managing farm equipment or transporting meat after slaughter.In addition to energy consumption and greenhouse emissions, animal agriculture produces a great amount of pollution and consumes substantially more water than plant agriculture. Some of this effect arises merely from the fact that eating animals is less efficient than eating plants -- a single animal must consume vast quantities of plants before it is slaughtered, which means that all the energy, water and other resources used to produce those plants are ultimately going to the production of a much smaller quantity of food.