T-bone steak, or icebergs? Pretty soon, we'll have to make a choice, says Lord Stern of Brentford, a leading climate-change expert and author of the 2006 global warming report the Stern Review. "Meat is a wasteful use of water and creates a lot of greenhouse gases," says the former chief economist of the World Bank. "A vegetarian diet is better." Stern, now the I.G. Patel Professor of Economics at the London School of Economics, admits he is not a strict vegetarian, but said that eventually global attitudes about meat consumption will change: "People change their notion of what is responsible. They will increasingly ask about the carbon content of their food." The economist, who was being interviewed by the Times of London, implored President Obama to attend the U.N. meeting in Copenhagen, where he believes U.S. leadership is "desperately needed," and that in order to avoid further, possibly irreparable damage to the planet, the world will need to halve its greenhouse-gas emissions by 2030. Unsurprisingly, Stern's comments garnered a strong reaction from the U.K. meat industry: "Going vegetarian is not a worldwide solution," said Jonathan Scurlock of the National Farmers Union.