Associated Press: The correct types of biofuels must be promoted to successfully combat climate change unlike corn, which has a very low productivity, a senior U.N. environment official said Tuesday. Plans to expand biofuel production in many parts of the world are coming under closer scrutiny following a recent spike in food prices and fears that two industries may be competing. “I think it’s a question of making sure the correct biofuels are being promoted, and not others,” …