Climate Central: The mean annual climate of the average location on Earth will slip past the most extreme conditions experienced during the past 150 years and into new territory by between 2047 and 2069, depending on the amount of climate-warming greenhouse gases that are emitted during the next few decades, a new study found. The study, published Wednesday in the journal Nature, used a new index to show for the first time when the climate -- which has been warming during the past century in response to manmade pollution...