Live Science: It's time to ditch the goal of keeping Earth's warming to less than 2 degrees Celsius (3.6 degrees Fahrenheit), researchers argue in a new opinion piece a suggestion likely to receive pushback from many in the climate science and policy community. In 2009, at the United Nations Climate Change Conference, international negotiators drew a line in the sand: Humanity must not let the planet get hotter, on average, than 2 degrees Celsius above preindustrial levels. This number has been the focal point...