"The biggest change anyone could make in their own lifestyle would be to become vegetarian," McCartney, a longtime vegetarian and advocate of vegetarianism, said. "I would urge everyone to think about taking this simple step to help our precious environment and save it for the children of the future."

McCartney says the amount of land and water used to maintain the meat industry makes it a major contributor to climate change and complains that most environmental groups do not list vegetarianism as one of their top priorities.

"It's very surprising that most major environmental organizations are leaving the option of going vegetarian off their lists of top ways to curtail global warming," he said.

A 2006 United Nations report found that cattle-rearing generated more greenhouse gases than transportation.