Astronomer and blogger Phil Plait has a good summary of climate concerns here.
As he notes, the U.S. National Oceanic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA), and the independent research group Berkeley Earth all concur that the year 2016 was the warmest on record for the Earth’s mean surface temperature, breaking the records previously set in 2015 and before than in 2014. In fact, 15 of the hottest 16 years have occurred since 2000, and the previous record in 1998 wasn’t that long before.
Incidentally, Plait is moving his blog from Slate to SyFy Wire, where he continues to write about a variety of astronomical topics, including a climate change. See for example his piece from a few days ago on the supposed “pause” in global warming.