Nov 24, 2015

Record Hot Year, 2015

World Weather Attribution
  • Estimates the 2015 global temperature anomaly to be 1.05ºC (1.89ºF) above the 1850–1900 average that the IPCC takes to be “pre-industrial"
  • Determines the year 2015 is therefore likely to be remembered as the first year that two symbolic thresholds were set: the 1ºC (1.8ºF) temperature anomaly threshold and the 400 parts per million (ppm) CO2 threshold
  • Determines that of the 1.05ºC temperature departure from pre-industrial, roughly 1.0ºC is due to the anthropogenic forcing, about 0.05ºC (0.09ºF) to 0.1ºC (0.18ºF) is due to El Niño and about 0.02ºC (0.04ºF) is due to higher solar activity
  • Bases analysis on well-established techniques from the peer-reviewed literature (Foster and Rahmstorf, 2011; Suckling et al, 2015)