Guest Post by Bob Tisdale
This post confirms what most of us suspect based on the history of global surface temperature data responses to strong El Niño events. That is, if global surface temperatures respond similarly to past strong El Niños, the 2016 values should be higher than 2015.
TABLE OF SURFACE TEMPERATURES DURING EVOLUTION AND DECAY YEARS OF STRONG EL NIÑOS, AND THEIR DIFFERENCE
Table 1 lists the global temperature anomalies from GISS, NOAA NCEI and UKMO for the evolution and decay years, and their differences, during the eight strong El Niño events of 1957/58, 1965/66, 1972/73, 1982/83, 1987/88, 1991/92, 1997/98, and 2009/10. I’ve also listed the 2015 values for the 2015/16 El Niño. For this discussion, I’ve defined a strong El Niño as one where the peak NOAA Oceanic NINO Index value equals or exceeds 1.5 deg C. The annual global temperature anomaly values are as provided by the suppliers…that is, they have not been normalized to account for the differences in base years in Table 1.
(Table with all El Niño events, regardless of strength, is here.)
The 1991/92 El Niño was the only strong El Niño event where the decay year was cooler than the evolution year. That unusual response, of course, would typically be attributed to the sun-blocking aerosols emitted by the explosive volcanic eruption of Mount Pinatubo in 1991. On the other hand, El Chichon erupted in 1982 during the 1982/83 El Niño and global surface temperatures were higher in 1983 than in 1982…but the eruption of El Chichon in 1982 is said to have had a lesser impact on global temperatures than 1991’s Mount Pinatubo and the 1982/83 El Niño was stronger than the 1991/92 El Niño.
THE RECENT UNEXPECTED DOWNTICKS
Curiously, though, there have been recent sizeable multi-month downticks in both GISS and NCEI surface temperature data that indicate an early decay of global surface temperature responses to the 2015/16 El Niño, when compared to that of the comparably sized 1997/98 El Niño. (Still waiting for the HADCRUT4 data for May 2016.) See Figure 1. Note that the data in Figure 1 have been normalized to the first 3 months of the respective first years for an easier visual comparison of the responses of global surface temperatures to the two El Niños of similar strength. Contrary to nonsensical alarmist claims, I am not hiding the fact that surface temperatures are reportedly higher in 2015/16 than they were in 1997/98.
IF, great big if, the early decay of [the global temperature response to] the 2015/16 El Niño persists, there’s a chance that global surface temperatures in 2016 will not be higher than 2015…and that would be unusual.
GISS LOTI data are here.
NCEI data can be found here.
Annual UKMO HADCRUT4 data are here.
UPDATE: I’ve added a clarification in brackets to the closing paragraph.