Reuters: The UN's Paris climate conference, designed to reach a plan for curbing global warming, may instead become the graveyard for its defining goal: to stop temperatures rising more than 2 degrees Celsius above pre-industrial levels. Achieving the 2C (3.6 Fahrenheit) target has been the driving force for climate negotiators and scientists, who say it is the limit beyond which the world will suffer ever worsening floods, droughts, storms and rising seas. But six months before world leaders convene in...