The dangers of climate change are mounting so rapidly that they could soon overwhelm the ability of both nature and humanity to adapt unless greenhouse gas emissions are quickly reduced, according to a major new scientific report released on Monday. The report by the Intergovernmental Panel on Climate Change, a body of experts convened by the United Nations, is the most detailed look yet at the threats posed by global warming. It concludes that nations aren’t doing nearly enough to protect cities, farms and coastlines from the hazards that climate change has unleashed so far — such as record droughts and rising seas — let alone from the even greater disasters in store as the planet continues to warm. […]