 When we're looking at the footprint of a piece of food, whether it's a piece of wheat or a piece of beef or a piece of chicken or whatever, we have to look at all the things that had to go on in order for that food to be produced. This stuff gets incredibly convoluted, but Mike Berners-Lee is going to help me get to the bottom of it. I'm Mike Berners-Lee. I'm a professor at Lancaster University. He's a walking, talking carbon footprint calculator. I have written some books, including How Bad Are Bananas? The Carbon Footprint of Everything.