Source: Reuters * Exact causes unknown for lack of warming from 1999-2008 * The underlying reason for cold winter not known * Climate science in focus after email scandal, errors By Gerard Wynn and Alister Doyle LONDON/OSLO, Feb 25 (Reuters) - Climate scientists must do more to work out how exceptionally cold winters or a dip in world temperatures fit their theories of global warming, if they are to persuade an increasingly sceptical public. At stake is public belief that greenhouse gas emissions are warming the planet, and political momentum to act as governments struggle to agree a climate treaty...