The latest state of the global climate report reveals 2015 was a record-breaking year, following on from 2014, which recorded the previous highest average global surface temperature.
In 2015 - the warmest year on record for the second year in a row - the Earth's surface reached more than 1°C above pre-industrial levels for the first time since records began and the levels of dominant greenhouse gases again reached new high levels.
Dr Kate Willett - a senior scientist with the Met Office, specialising in climate monitoring - leads the Global Climate chapter of the report published in the Bulletin of the American Meteorological Society (BAMS). She said: "Looking at a range of climate measurements, 2015 was yet another a highly significant year. Not only was 2015 the warmest year on record by a large margin, it was also another year when the levels of dominant greenhouse gases reached new peaks. Measurements from a series of monitored glaciers showed continuing retreat for the 36th consecutive year, and sea levels and ocean heat content were all at their highest levels."
The most prominent climate feature of 2015 was the development of an strong What is El Niño? event - the development of a warm pool across the east-central Tropical Pacific Ocean - which helped raise global average surface temperatures in 2015 and CO2 levels. One of the most significant impacts of 2015 was the changes to the world's water, or hydrological cycle brought by the strong El Niño. Kate Willett added: "Drier-than-average conditions were common, with below average soil moisture and groundwater storage contributing to intense and widespread fires across Indonesia. Globally there was a 75% increase in the extent of land experiencing severe drought, bringing hardship to many communities."
The State of the Global Climate report is compiled by more than 460 authors - from 62 countries - including significant contributions from the Met Office, which leads the report's Global Climate chapter. The report is led by NOAA National Centers for Environmental Information.
Commenting on the report, Thomas R. Karl, L.H.D., Director, NOAA National Centers for Environmental Information, said: "This 'annual physical' of Earth's climate system showed us that 2015's climate was shaped both by long-term change and an El Niño event. When we think about being climate resilient, both of these time scales are important to consider. Last year's El Niño was a clear reminder of how short-term events can amplify the relative influence and impacts stemming from longer-term global warming trends."
"The State of the Climate report continues to be critically important as it documents our changing climate. American Meteorological Society (AMS) is proud to work with so many from the science community to make this publication happen," said Keith Seitter, Executive Director of the AMS.
The State of the Climate in 2015 is the 26th edition in a peer-reviewed series published annually as a special supplement to the BAMS. The journal makes the full report openly available online.