BBC: Nobel laureate and former United States vice president Al Gore has urged Americans to make a total shift from fossil fuels to renewable energy within 10 years. Mr Gore says his goal, while similar to some of the toughest goals undertaken by man, is achievable and affordable. But the 10-year plan has been questioned by critics. It is an ambitious target, but one that he claims will help solve global warming and at the same time renew America’s economy by ending its …