Wednesday, January 20, 2016

Global Temperature in 2015 - by James Hansen et al

Global surface temperature in 2015 was +0.87°C (~1.6°F) warmer than the 1951-1980 base period in the GISTEMP analysis, making 2015 the warmest year in the period of instrumental data.  The 2015 temperature was boosted by a strong El Niño, nearly of the same strength as the 1998 “El Niño of the century”.  The updated global temperature record makes it clear that there was no global warming “hiatus”.  Global temperature in 2015 was +1.13 (~2.03°F) relative to the 1880-1920 mean.  Accounting for interannual variability, it is fair to say that global warming has now reached ~1°C, almost ~2°F.

Update of the GISS (Goddard Institute for Space Studies) global temperature analysis (GISTEMP), finds 2015 to be the warmest year in the instrumental record. (More detail is available at and; figures in this summary are available from Makiko Sato on the latter web site.)  Unlike the prior three record years, 2014, 2010 and 2005, each of which exceeded the preceding record by only a few hundredths of a degree, 2015 smashed the prior record by more than 0.1°C.  The only prior record-raising jump of annual global temperature as large, probably slightly larger, was in 1998.  The 1998 temperature was boosted by the strong 1997-98 “El Niño of the century.”  The 2015 temperature was boosted by an El Niño of comparable magnitude.

Fig. 1. Global surface temperatures relative to 1951-1980 in the GISTEMP analysis, which employs GHCN.v3 for meteorological stations, NOAA ERSST.v4 for sea surface temperature, and Antarctic research station data. (Credit: Click to Enlarge.The high 2015 global temperature should practically terminate discussion of a hypothesized “global warming hiatus”, as the past two warm years remove the impression that warming has plateaued (Fig. 1).  Close examination (Fig. 1b) reveals that the warming rate of the past decade is less than in the prior 30 years, but such fluctuations are not unusual and can be accounted for by a combination of factors.

Read more at Global Temperature in 2015

No comments:

Post a Comment