Sir Paul McCartney has turned his hand to rapping in an attempt to persuade people to sign up for meat-free Mondays.

The former Beatle, widely considered to be one of the greatest living songwriters, made the plea for people to go vegetarian once a week before the UN climate summit, which takes place on Tuesday in New York.

In the video posted on YouTube, he says: "I need your help, all I want you to do is just log in on pledge.meatfreemondays.com and pledge your support to the idea of meat-free Mondays … Please do it. We'll send all these pledges to the politicians, and then they'll do something about it."

McCartney then ends with a short rap in a somewhat affected accent, accompanied by animated hand gestures, finger-clicks and hand claps, in which he says: "Pledge.meatfreemondays.com, pledge.meatfreemondays.com. You can do it right now please."

The Food and Agriculture Organisation of the United Nations estimates that livestock production is responsible for 14.5% of global greenhouse gas emissions, although other groups believe the figure is much higher.

More than 800,000 people had signed up to the pledge by Sunday afternoon. Other celebrity backers include Jamie Oliver, Gwyneth Paltrow, Kevin Spacey and Ricky Gervais.