State of the climate in 2014

• Main Author: Aaron-Morrison, A.P.
• Format: Journal/Newspaper
• Language: unknown
• Subjects: Atmospheric radiation; Atmospheric temperature; Atmospheric thermodynamics; Carbon dioxide; Enthalpy; Glaciers; Global warming; Greenhouse gases; Melting; Nitrogen oxides; Ozone layer; Permafrost; Records management; Sea ice; Sea level; Solar radiation; Storms; Surface properties; Surface waters; Atlantic meridional overturning circulations; Atmospheric concentration; Direct radiative forcing; Global surface temperature; Greenhouse-gas forcing; Pacific decadal oscillation; Sea surface temperature (SST); Summer monsoon rainfall; Rain; Ice; permafrost
• Online Access: https://hdl.handle.net/20.500.12110/paper_00030007_v96_n7_pS1_AaronMorrison

Most of the dozens of essential climate variables monitored each year in this report continued to follow their long-term trends in 2014, with several setting new records. Carbon dioxide, methane, and nitrous oxide-the major greenhouse gases released into Earth's atmosphere-once again all reached record high average atmospheric concentrations for the year. Carbon dioxide increased by 1.9 ppm to reach a globally averaged value of 397.2 ppm for 2014. Altogether, 5 major and 15 minor greenhouse gases contributed 2.94 W m -2 of direct radiative forcing, which is 36% greater than their contributions just a quarter century ago. Accompanying the record-high greenhouse gas concentrations was nominally the highest annual global surface temperature in at least 135 years of modern record keeping, according to four independent observational analyses. The warmth was distributed widely around the globe's land areas, Europe observed its warmest year on record by a large margin, with close to two dozen countries breaking their previous national temperature records; many countries in Asia had annual temperatures among their 10 warmest on record; Africa reported above-average temperatures across most of the continent throughout 2014; Australia saw its third warmest year on record, following record heat there in 2013; Mexico had its warmest year on record; and Argentina and Uruguay each had their second warmest year on record. Eastern North America was the only major region to observe a below-average annual temperature. But it was the oceans that drove the record global surface temperature in 2014. Although 2014 was largely ENSO-neutral, the globally averaged sea surface temperature (SST) was the highest on record. The warmth was particularly notable in the North Pacific Ocean where SST anomalies signaled a transition from a negative to positive phase of the Pacific decadal oscillation. In the winter of 2013/14, unusually warm water in the northeast Pacific was associated with elevated ocean heat content anomalies and elevated sea ...