Way back in June, John Christy and I called 2015 as being the warmest year on record … in the surface thermometer data. Given the strong El Nino in progress, on top of the official thermometer data warming trend, this seemed pretty obvious.

Of course, everyone has their opinions regarding how good the thermometer temperature trends are, with periodic adjustments that almost always make the present warmer or the past colder.

But I’m not going there today ….

Instead, I’m going to talk about our only truly global dataset: the satellite data. With the November 2015 data now in, it’s pretty clear that in our UAH analysis 2015 will only be the 3rd warmest year since the satellite record began in 1979. Based upon my calculations, this will be true no matter what happens in December (barring Armageddon).

Here are the yearly rankings, for which I assumed the December 2015 anomaly will be +0.40 C:

The years are displayed with the warmest on the left, and the coldest on the right. The color coding and arrows have to do with El Nino years, discussed below.

Will 2016 be a Record?

What is interesting is to consider the possibility that 2016 will indeed be a record warm year, even in the UAH (and probably RSS) satellite data. This is because the second year of El Nino year couplets is almost always the warmest, and 2015 is only the first year.

In the plot above I have color-coded the four previous major El Nino year pairs: 1982–83, 1987–88; 1997–98; and 2009–10. In three of those (all except 1987–88), the second year was much warmer than the first year. This means there is a good chance that 2016 will be a record warm year.

But as 1987–88 shows, it’s not guaranteed….

If the current El Nino unexpectedly fizzles in the next few months—OR—if this El Nino transitions unusually rapidly into a strong La Nina (like the 1987–88 event), then 1998 might not be beaten for the warmest year. Mother Nature is full of surprises, and I still believe she is mostly in control.

If I simply average the previous four El Nino events together as an estimate of what will happen next year, then 2016 would be 0.25 C warmer than 2015. This would cause it to edge out 1998 as the record warmest year by 0.02–0.03 deg. C [which is within the margin of error, which might be more like 0.04–0.05 deg. C].

But I’m not making any bets.

[Meanwhile …]

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for November, 2015 is +0.33 deg. C, down from the October, 2015 value of +0.43 deg. C:

The global, hemispheric, and tropical LT anomalies from the 30-year (1981–2010) average for the last 11 months are:

YR   MO GLOBE NH     SH       TROPICS
2015  01   +0.28     +0.40  +0.16    +0.13
2015  02   +0.17     +0.30  +0.05    -0.06
2015  03   +0.16     +0.26  +0.07    +0.05
2015  04   +0.08     +0.18  -0.01     +0.09
2015  05   +0.28     +0.36  +0.21    +0.27
2015  06   +0.33     +0.41  +0.25    +0.46
2015  07   +0.18     +0.33  +0.03    +0.47
2015  08   +0.27     +0.25  +0.30    +0.51
2015  09   +0.25     +0.34  +0.17    +0.55
2015  10   +0.43     +0.64  +0.21    +0.53
2015  11   +0.33     +0.43  +0.23    +0.53
The tropics continue warm due to El Nino conditions, but the temperature in recent months seems to have plateaued despite the climatological expectation of increasing temperature as we approach peak El Nino warmth in the next few months. This plateau, of course, could end at any time.

[This post is adapted from Dr. Spencer’s own blog posts on here and here.]