NEW YORK - Morrissey, the singer known for his strident defense of animal rights, has demanded that upcoming Live Earth concerts aimed at fighting climate change go vegan. In a characteristically intense letter addressed to former US vice president Al Gore, who is spearheading the shows, Morrissey highlighted the lower carbon footprint of a plant-based diet. “Serving meat and dairy products at an event to combat climate change is like selling pistols at a gun-control rally,” Morrissey said in the letter released Wednesday by People for the Ethical Treatment of Animals. “Your responsibility is to alert people to a crisis, not sell out to the vendors responsible for it,” he wrote. “I don’t mean offering a vegan option — I mean not serving animal products at all. Otherwise, the event will make no sense-it’ll be ‘greenwashing.’”  Gore has teamed up with “Happy” singer Pharrell Williams to organize Live Earth concerts on June 18 aimed at building momentum for a global agreement on climate change at a UN conference late this year in Paris. Live Earth shows are planned on each inhabited continent, with one concert in the New York area, although organizers have not announced the lineups, let alone the menu. Gore, who shared a Nobel Peace Prize for his climate activism, was reported in 2013 to have gone vegan but he is far less vocal about his diet than Morrissey. The British singer — whose albums with his former band The Smiths included the 1985 classic “Meat is Murder” — demands that all venues where he performs go vegetarian. Morrissey — who once walked off stage at the Coachella festival in California when he smelled a barbecue — boasted that New York’s Madison Square Garden was taking meat off the menu during his show on his upcoming tour.