BBC: The planet will be in “huge trouble” unless Barack Obama makes strides in tackling climate change, says a leading scientist. Prof James McCarthy spoke on the eve of the annual meeting of the American Association for the Advancement of Science (AAAS), which he heads. The US president has just four years to save the planet, said Prof McCarthy. If major policy changes do not happen within Mr Obama’s term of office, they will not happen at all, he warned. “We have a …