By the widest margin on record
Last year was the warmest year on record, breaking previous highs by the largest margins on record.
In an annual report from the National Oceanic and Atmospheric Administration, officials said the overall global temperature was up 1.62°F (0.90°C) from the 20th century average, breaking the previous record set in 2014 by 0.29°F (0.16°C). New globally-averaged highs were registered both in land surface and sea surface temperatures.
This is the fourth time a new global record has been set in the 21st century. Ten out of 12 months in 2015 saw new monthly records set.