Temperature Updates for January 2018 - Surface Data

A quick update on global temperatures for January 2018, focusing on surface data - specifically that for NASA's GISTEMP, and the Met Office Hadley Centre HadCRUT.

Anomalies

GISTEMP gives the anomaly for January as 0.78°C, compared with the 1951-1980 base period. This makes January 2018 the 5th warmest January in their data set.

HadCRUT gives the anomaly for January as 0.553°C, compared with the 1961 - 1990 base period. This makes 2018 the 8th warmest January.

These graphs show the monthly data, a 12 month rolling average and the trend since 1970 (the period I use for the predictions). They also show the current month as a red dot.

Comparisons

Here are all the anomalies for January 2018. For each data set the temperature has been adjusted to show the anomaly against the common base period of 1981 - 2010.

GISTEMP	+0.325°C
HadCRUT	+0.229°C
NOAA	+0.260°C
BEST	+0.365°C
UAH 6	+0.260°C
RSS 4	+0.401°C

Predictions for 2018

As we only have one month so far these predictions are not likely to be too meaningful. They are based on extrapolations from previous January figures, and a linear trend since 1970, but as January only makes up 1/12 of the year, the predictions are going to be very close to simply looking at the linear trend. As a result both predictions have 2018 finishing warmer than January, which seems unlikely. The trend is probably inflated slightly by the recent succession of very hot years.

For GISTEMP the prediction is for 2018 to be 0.813 ± 0.139°C.

For HadCRUT the prediction for 2018 is 0.64 ± 0.156°C.

Temperature Update - January 2018, the Satellites

This post starts my ongoing monthly summaries of global temperature anomalies from different data sets. In this I'll look at the two main satellite data sets - UAH 6, and RSS 4.

The anomalies (relative to their respective base periods) for January 2018 are

• UAH 6: +0.26°C (Relative to 1981 - 2010)
• RSS 4: +0.546°C (Relative to 1979 - 1998)

Translating RSS to the UAH base period would give RSS an anomaly of +0.401°C. Both are cooler than December 2017 - UAH down 0.15°C, RSS down 0.044°C.

In the UAH set January 2018 is the 10th warmest January. In the RSS set it is the 7th warmest.

These graphs show the monthly data across the satellite era, along with the trend and the 12 month moving average. January 2018 is highlighted in red.

In both cases Janury 2018 is very close to the long term.

Forecasts

Using my simple statistical model, the predictions for 2018 are that UAH will have an annual anomaly of 0.256 ±0.185°C, and that RSS will have an anomaly of 0.551 ± 0.167°C.

Note that in both cases the most likely prediction for 2018 is very close to the values for January. This is to be expected given the the fact that January was very average. But of course the uncertainty is large.

Predicting a specific ranking is probably foolish at this point, but both sets are looking to finish close to the current 5th warmest year of 2015. UAH has around a 55% chance of finishing below 2015 and 45% above, whilst RSS has more or less equal chances of finishing above or below 2015.

If UAH finishes below 5th place, it could end up just about anywhere as there are a lot of years with very similar values. It's unlikly to finish 1st or 2nd but there is around a 1 in 5 chance of UAH finishing 3rd or 4th.

For RSS there's a prety good chance (~40%) that it will finish between 2005 and 2015 for 6th place (owing to the big gap between the two), but only a slim chance (less than 10%) that it will finish below 6th. Though if it does it could finish just about anywhere. It has about a 1 in 7 chance of finishing 2nd.

As always these probabilities are based solely on past statistical inference and do not factor in the probability of a La Niña this year.

One Last Thing

As there will likely be a lot of talk of a returning pause as the next La Niña takes hold, it's worth seeing where we are in comparison to the previous powerful El Niño of 1998. (What am I saying? There have been talk of a return of a pause since 2016.) Anyway, this graph compares the 5 years surrounding 1998, with those surrounding 2016.

UAH 6 shows the least warming since 1998. But even with that data set, whilst the peaks of the two El Niños are similar, the years before and after have been considerably warmer.

Christopher Monckton Tampers With the IPCC

Christopher Monckton of Brenchley is back at Watt's Up With That with the first of what promises to be a series of articles about IPCC projections. The article is Tamper, tamper! How They failed to hide the gulf between predicted and observed warming . In it he revisits his usual argument that the rate of warming in the slowest warming data set (UAH 6) does not match the rate of warming predicted in the oldest IPCC report from 1990. He also says that all the data sets have been tampered with - in the article he objects to the changes to RSS 4, but in the comments he also says that the tampering charge applies to all data sets including UAH 6. The only reason for using that particular data set was that it was the first to be released, and not because it happens to be the coolest.

He uses the oldest IPCC projections, by definition the least reliable, from 1990 and the slowest warming data set (UAH 6) to claim that there has only been half as much warming as predicted.

As Fig. 1 shows, in the 39 years 1 month from December 1978 to December 2017, the planet has warmed by half a Celsius degree. But that is equivalent to 1.28 C°/century, or little more than one-third of the 3.3 C°/century predicted with substantial confidence by IPCC in 1990 and also by the fifth-generation general-circulation models of the Climate Model Intercomparison Project in 2013.

This is wrong on most counts. He quotes the 1990 IPCC report as saying with substantial confidence a rate of warming of 3.3°C / century. This figure does not appear in the report, and the figure they do state (0.3°C / decade) is not described as having substantial confidence. What the report says is they have ... substantial confidence that models can predict at least the broad scale features of climate change. (My emphasis.)

He also claims the latest IPCC projections are the same as those from the 1990s, but this is also wrong. His 3.3°C / century warming is somewhere between two of the IPCC scenarios, but only for long term warming, up to the end of the century. In the short term it says all scenarios are similar and projects between 0.3 and 0.7°C warming between 1995 and 2025 (using 20 year averages). Using Monckton's trick of converting all warming projections to linear trends this is a rate of warming of between 1°C / century and 2.3°C / century. Even UAH 6 is within these bounds.

But, what interests me most is where Monckton gets his 3.3°C / century figure from, and why this is faster than what he was claiming they said only a couple of years ago. Back in May 2016 Monckton introduced the Global Warming Speedometer. (Never to be seen again). In this he claimed the 1990 IPCC report predicted a rate of warming of 2.8°C / century, with a lower bound of 1.9°C / century.

What the 1990 IPCC Report Said

The main description of future warming is made in page xxii of the first IPCC report. They say that temperatures are likely to raise at a rate of 0.3°C / decade. They then give figures for the amount of warming both from the pre-industrial period and the present (ie 1990). They define the pre-industrial period as 1750-1800 (page 22) or just 1765 (page 177).

They state that by the the end of the century temperatures will be 4°C warmer than the pre-industrial period, and 3°C warmer from present. They also say this will mean that by 2025 global temperatures will be 2°C warmer than pre-industrial levels, and 1°C from present temperatures.

This is illustrated with this graph, showing the likely warming and the upper and lower bounds.

However they define the pre-industrail period, it's clear from their figures and the graph that they consider there has been 1°C of warming from pre-industrail to 1990. What's not clear is how precise these figures are meant to be, all temperature increases are given to whole degrees.

The projected 1°C by 2025 would translate to an average warming rate of 2.8°C / century, and this appear to be how Monckton calculated the rate for his speedometer, although he credits this to page xxiv. This is interesting as that page suggests a slower rate of warming.

Page xxiv quotes a projection of 1.8°C above pre-industrial levels by 2030. Obviously this is less than the 2°C by 2025 they give on page xxii. Taking this with the supposed 1°C warming up to present would suggest a projected 0.8°C warming over the 40 years from 1990 to 2030; a rate of 2°C / century, with low and high estimates of 1.4°C and 3.0°C / century. This would mean most data sets are well within the projected warming rates, and UAH 6 is only slightly below the lower estimate.

So why does Monckton believe that page xxiv is actually claiming a warming rate of 3.3 °C / century? In response to a question from DWR54 he says,

In reply to the furtively anonymous “DWR54” p. xxiv of IPCC (1990) says: “The numbers given below are based on high-resolution models, scaled to be consistent with our best estimate of global mean warming of 1.8 C by 2030 [compared with pre-industrial temperatures] … the numbers below should be reduced by 30% for the low estimate or increased by 50% for the high estimate.”

There had been 0.45 K global warming in the industrial era, so IPCC was predicting 1.35 K of warming over 4.1 decades, equivalent to 3.3 K/century. In the passages cited by “DWR54”, IPCC rounded this value to 3 K.

His entire argument is based on the claim that there had only been 0.45°C warming from the pre-industrial period by 1990, and that the IPCC were predicting an additional 1.35°C warming by 2030. This does not agree with anything they say elsewhere and does not agree with their graph. Here (in red) is what Monckton's 1.35°C of warming looks like.

Monckton's 0.45°C figure probably comes from page 199 of the IPCC report. This is a chapter on instrument measurements, in which they say that the world is probably 0.45 ± 0.15°C warmer than the late 19th century.

There are many problems with Monckton using this figure. For a start it isn't for warming from the pre-industrial period, but from the late 19th century. Then there's the way he ignores the large uncertainty in the stated figure. But the big problem is that whatever the merits of the 0.45°C figure, it isn't the one the IPCC used when they stated the warming rates from the pre-industrial period on pages xxii and xxiv. You cannot simply take an unrelated figure from a different part of the report, use it to add an extra 0.55°C to the expected warming and claim that's what the IPCC really meant - with substantial confidence.

In short - Monckton has literally made up a figure, and then quoted it as if it was a direct figure from the IPCC.

Monckton's Own Predictions

In commenting on Monckton's article I couldn't resist pointing out one of his own predictions, made in front of a congressional hearing in 2009. He claimed then that global temperatures might only rise by 0.5°F by the end of the century, that is about 0.28°C. This means that by Monckton's own logic, temperatures are warming more than 4 times faster than his prediction, even using the slowest rising UAH data.

When I mentioned this in the comments, Monckton said he couldn't remember making such a prediction

In reply to Bellman, I do not recollect having predicted in 2009 that global warming would be only 0.25 K/century. I said that at that time the warming rate was equivalent to 0.25 K/century. I have published a series of papers in which the best estimate of warming is around 1.2-1.3 K/century. That warming rate, and no higher rate, is consistent with the officially estimated net anthropogenic forcings in the industrial era.

His exact words, both in written and spoken testimony to congress, were

This century we may warm the world by half a Fahrenheit degree, if that.

The Right Honorable Christopher Walter Monckton, Third Viscount Monckton of Brenchley before The Energy & Commerce Committee of the House of Representatives Washington, DC, Wednesday, 25 March, 2009

And here's the video of him saying it

It's not clear why he thinks the warming rate at the time was 0.25°C / century. At the time he was saying there had been rapid cooling (but that's another story). Possibly he did make a mistake both in his written and spoken testimony - elsewhere in the speech he suggests warming may be as much as 2°F by the end of the century. But it does follow another habit of stating predictions with no indication of doubt. For example in 2015 he said:

No warming has yet arisen this century. Warming may be 0.6 K by 2100, could be as low as 0.4° K and will not exceed 1° K.

Using IPCC numbers we can expect only half a degree of warming this century. Time to Panic?

Now he's saying the most likely warming rate is 1.2 - 1.3 °C / century. Yet he wants to hold the IPCC to account for projections made almost 30 years ago.