New study calculates climate change's economic bite will hit about $38 trillion a year by 2049

In a first, delegates at UN climate talks agree to transition away from planet-warming fossil fuels

US joins in other nations in swearing off coal power to clean the climate

Top warming talks official hopes for 'course correction' and praises small steps in climate efforts

Tens of thousands march to kick off climate summit, demanding end to warming-causing fossil fuels