Last year was the warmest on Earth since record keeping began in 1880, according to a National Climatic Data Center report.
In 2014, the average global temperature was 58.24°F (14.58°C), which was 1.24°F (0.69°C) above the 20th-century average.
That made for the highest average temperature recorded in 135 years, surpassing previous records set in 2005 and 2010 by 0.07°F (0.04°C), according to the report. The fourth warmest year was recorded in 1998.
Last year also saw the hottest December on record.
Nine of the 10 warmest years on record, including 2014, have occurred during the 21st century, the report noted.
The global annual temperature has increased at an average rate of 0.11°F (0.06°C) per decade since 1880, and at an average rate of 0.28°F (0.16°C) per decade since 1970.