McCartney claimed livestock produce more carbon emissions than transport and suggested going vegan or finding alternative sources of animal-based foods, the Telegraph reported Tuesday.
"There are many other kinds of milk available. Why don't we try drinking rats' milk and dogs' milk?" she asked.
"Eighty percent of global warming comes from livestock and deforestation," McCartney said in helping start a campaign by the vegetarian group, Viva. "I'm not telling people to go vegan overnight. But if they stop drinking their cows' milk lattes, maybe this sort of thing won't have to happen."