McCartney is a vocal vegetarian. He and his deceased wife, Linda, created a line of vegetarian food products under the Linda McCartney brand. McCartney has long supported animal rights efforts and the People for the Ethical Treatment of Animals and other such groups often have booths set up at concert venues when he performs.
McCartney argues that food production— from farm to fork — accounts for 20 percent to 30 percent of global green house gas emissions. He contends that livestock production is responsible for around half of these emissions.
The Associated Press contributed to this article.