According to analyses by NASA and NOAA scientists, 2015 was the warmest year on record, with average surface temperatures the highest they’ve been since 1880. The above video shows the long-term warming trend since 1880 as a five-year rolling average. The baseline average is from 1951 to 1980; orange colours are warmer than that average, blue colours cooler. (Credit: GSFC Scientific Visualization Studio.)