Why surface temperature matters
Of all the planets in our neighborhood, Earth has a surface temperature that is uniquely friendly to life. That friendliness is the result of a balancing act between incoming sunlight and outgoing thermal energy—the heat radiated back to space by every part of the Earth system, from land to oceans to clouds and, especially, by the gases in the atmosphere. Surface temperature is one of the most direct of several signals that indicate the status of Earth’s heat budget. Earth’s long-term warming trend shows that the balance has changed: the atmosphere absorbs and radiates more heat (thermal infrared energy) than it used to.
Conditions in 2014
Globally averaged surface temperature for 2014 was 0.27° -0.29° Celsius (0.49°-0.52°F) above the 1981–2010 average. Depending on the small differences among different data sets, 2014 was either the warmest or tied-for-warmest year since records began in the mid-to-late 1800s.
Overall, the globally averaged annual temperature over land was 0.37-0.44° Celsius (0.70° -0.79° F) above the 1981-2010 average, ranking it as the warmest year in some datasets and fourth-warmest in others. Land surfaces over Eurasia and western North America were particularly warm in 2014, and the frequency of warm temperature extremes was above average for all regions apart from North America.
The only land areas with widespread temperatures below the 1981-2010 average were the eastern half of the contiguous United States, central and southern Canada, and parts of central Asia. Eastern North America, including the eastern U.S., was relatively cool for the majority of 2014, with some sharp cold air outbreaks early in the year.
In 2014, the globally averaged sea surface temperature was 0.21-0.27°C (0.34°-0.49°F) above the 1981-2010 average–the highest on record according to all datasets. Even though conditions across the tropical Pacific Ocean were ENSO-neutral to marginal, sea surface temperatures averaged across the larger Pacific basin were much warmer than average in 2014. Every major ocean basin had at least one region with temperatures more than 1°C warmer than average during 2014. Some areas across the Atlantic, South Pacific, and northwestern Pacific Oceans experienced below-average temperatures.