"During the next week, the official climate agencies around the world that are responsible for tracking the planet's average temperatures will almost certainly come to the same conclusion: 2015 was the warmest year on record. This would mean that 2015 would beat the previous warmest year, which occurred in 2014 — remember that?
The combination of a record strong El Niño event plus the highest amount of greenhouse gases in the atmosphere at any time in human history have given the climate system the equivalent of a Power Bar plus a shot of espresso. On Wednesday, one unofficial temperature tracking group, known as Berkeley Earth, revealed its determination that 2015 was by far the planet's warmest year, both on land and sea.
There's one especially important about fact about this group's determination: It was set up in early 2010 as an independent fact check of other surface temperature data sets, and led by a physicist — Richard Muller — who had previously been quite skeptical of mainstream climate science findings. Instead of proving surface data from government agencies like NASA and the National Oceanic and Atmospheric Administration (NOAA) wrong, the Berkeley group has consistently reaffirmed their data."