Hottest Year Time Again
The near-surface global temperature anomaly data for 2016 have been collected, selected, infilled, “adjusted” and analyzed. The results are in; and, again, they are anomalous. NASA GISS(Goddard Institute for Space Studies) and NOAA NCEI(National Centers for Environmental Information) both report the average anomaly for 2016 as 0.99oC. This represents an increase of 0.13oC for the NASA GISS anomaly, compared with 2015; but, an increase of 0.09oC for the NOAA NCEI anomaly, compared with 2015. Both NASA GISS and NOAA NCEI place the confidence limits on their reported anomaly at +/- 0.10oC, or approximately the same magnitude as the reported year to year global average anomaly change. Both NASA GISS and NOAA NCEI estimate that the influence of the 2015/2016 El Nino contributed 0.12oC to the increase in the reported anomaly for 2016, 0.01oC less than the global average anomaly increase reported by NASA GISS and 0.03oC more than the global average anomaly increase reported by NOAA NCEI. That is, essentially all of the 2016 global average temperature anomaly increase reported by both agencies was the result of the influence of the 2015/2016 El Nino, which was very similar in magnitude to the 1997/1998 El Nino, which are the two strongest El Ninos recorded in the instrumental temperature record. HadCRUT reported an average anomaly of 0.774oC, an increase of 0.14oC from the 2015 average anomaly. HadCRUT estimated similar confidence limits and a similar El Nino contribution.
All of the near-surface temperature anomaly products reported dramatic drops in their anomalies, beginning in the Spring of 2016, though these drops were from record high monthly peaks driven by the El Nino. The NASA GISS anomaly dropped from a high of 1.36oC to a December 2016 level of 0.81oC, a change of -0.55oC. The NOAA NCEI anomaly dropped from a high of 1.22oC to 0.79oC, a change of -0.43oC. The HadCRUT4 anomaly dropped from a high of 1.08oC to 0.59oC, a change of -0.49oC. This a variance of 0.12oC between the near-surface temperature anomaly products, approximately equal to the magnitude of the reported 2016 anomaly increases, the estimated impact of the 2015/2016 El Nino and half the confidence range claimed for the reported anomalies.
University of Alabama Huntsville (UAH) and Remote Sensing Systems (RSS) both reported that 2016 was 0.02oC warmer than 1998, which both sources still report as the previous warmest year in the satellite temperature record. Dr. Roy Spencer of UAH stated that the increase in the reported temperature anomaly between 1998 and 2016 would have had to be ~0.10oC to be statistically significant. The UAH anomaly dropped from a 2016 high of 0.83oC to a December 2016 level of 0.24oC, a change of -0.59oC. The RSS anomaly dropped from a 2016 high of 1.0oC to a December level of 0.23oC, a change of -0.77oC. Both the UAH and RSS anomalies show the dramatic impact of the 2015/2016 El Nino. Both anomalies suggest that the “Pause” has returned, since they show no statistically significant warming since at least 1998.
The question now is whether there will be a La Nina in 2017; and, if so, the extent to which it will further reduce the post El Nino anomalies.