Tracking 2016 - September Satellite Updates

Some Notes

This is an update to my ongoing look at forecasting the likelihood of 2016 setting a record for hottest calendar year in different data sets. It includes the last two surface data sets for August, and the satellite sets for September. See here for the previous update.

There are a few complications to mention first:

• HadCRUT has been updated to version 4.5.0.0. The changes are small, but the last couple of years have gained around 0.02 ° C compared to version 4.4.0.0. Details here

• RSS 3.3 has also had some adjustments, though there is no official mention of this. Again the changes are very small, similar to those for HadCRUT. Needless to say this has caused claims of disbelief at Watt's Up With That, the site that objected to satellite-deniers.

  Hot Whopper has more information about the changes.

• For some reason the data file for UAH beta 6 has not yet been updated, though 5.6 has. I'm using the values Roy Spencer reported in his blog, for now.

Although the changes to HadCRUT and RSS were very small and have little impact on any global trend, they might have an impact on the question of a record year. All my charts are based on the current data, so will show retrospective changes. There have undoubtedly been other updates to data, but so far I haven't been testing for changes. I'm only mentioning the RSS change as WUWT made such a fuss about it.

What's Happened Since the Last Post

NOAA and HadCRUT values for August have been released. Both show an increase in anomaly since July, but smaller than the increases for BEST and GISTEMP.

All the satellite data for September has been released (though UAH beta 6 only unofficially). All show an increase in anomaly from August. UAH beta 6 only increased by 0.01 °C, and this only because the August figure was reduced slightly. All others showed a more substantial increase.

Monthly anomalies: 1981 - 2010 base period

Current State of Predictions

Here are my usual 2 graphs showing how the forecast for 2016 has progressed over the year.

Monthly projections for 2016 margins over previous record year

Monthly projected probabilities of 2016 setting a new record

HadCRUT and RSS 3.3 both increased their probability of beating their respective records, whilst the probability for UAH beta 6 has continued to decrease - down to 71%. All others are close to certain to beat their records.

More About UAH beta 6

Whatever the merits of the UAH beta 6 set, and noting it is still in beta and details have yet to be published, it is the set most likely to fail to set a record. My guess is that it's an even split as to whether it does set a record, but most likely it will be very close to 1998, and could well be called a statistical tie.

Here's what UAH beta 6 looks like for 2016 and 1998. The dotted line shows the needed average anomaly for the last three months of the year, for 2016 to equal 1998.

Comparison of UAH beta 6 monthly anomalies for 1998 and 2016

The last three months of 2016 will need to be slightly warmer than the last three months of 1998 to beat the record, but 1998 had a very cold November.

However UAH beta 6 has already beaten the record for annual temperatures - if you define annual as 12 months rather than a calendar year. The last 12 months narrowly beat the previous peak in 1998 by 0.03 °C. It seem likely this will be the peak for the current 12 month rolling average as October 2015 was quite warm.

UAH beta 6 monthly anomalies and rolling 12 month average

This has also been the warmest 2 year period in UAH history. The last 24 months have been 0.09 °C warmer than any 24 consecutive moves before 2016), and may continue to increase for the next month or two.

UAH beta 6 monthly anomalies and rolling 24 month average

In fact you can take any whole number of years and UAH beta 6 is currently the warmest its been over that time frame.

Average Increase in Misleading Graphs from Heller

A post from Tony Heller (aka Steve Goddard), on his Real Climate Science blog (aka The Deplorable Climate Science Blog) contains some good illustrations of how to mislead with graphs. The post Massive Increase In Arctic Ice Reflects The NASA Increase In Fraud claims that an increase in global warming since 2012 in GISTEMP contradicts the claim of a recent slowdown in warming, and that this shows NASA are engaging in fraud.

In this post Heller is suggesting that this doubling of global warming contradicts an article by John J Fyfe et al, Making sense of the early- 2000s warming slowdown which claimed there had been a slowdown in the rate of warming between 2000 and 2014.

He demonstrates his argument with reference to a couple of graphs from the Wood For Trees site, and I'll follow suit by demonstrating the problems using the same site.

Graph 1

The first graph shows 5 year rolling average temperatures since 1995, and has labels indicating there has been no warming in satellite data, but rapid warming from NASA.

Wood For Trees

Nothing surprising here, some satellite data shows rather less warming this century than terrestrial data sets. Heller assumes RSS 3.3 is reliable and there must be a mistake in all the data sets that shows quicker warming, including RSS 4 and UAH 5.6. What is odd is that he chooses to only show data for land, rather than the more usual combined land and ocean.

As far as I can see the reason he's only showing land temperatures is because over this period RSS is showing less warming over land than over the oceans.

Wood For Trees

The main problem is with Heller's claim that Satellites also show that there has been no warming over land since 2000. The problem being that this is a false claim, as he could have easily seen if he'd only added the trend line to the graph.

Wood For Trees

RSS has been warming since 2000 over land - at a rate of 0.83 °C / Century (up to August 2016). Certainly a lot less than the trend for GISS, but not no warming.

This is presumably the reason Heller prefers to show a rolling 5 year average. It obscures what's been happening the last few years. Here's what the RSS land temperatures look like with a 12 month rolling average.

Wood For Trees

Graph 2

The second graph is used to illustrate the main claim in the article:

Undeterred by facts or science, Mann's buddy Gavin Schmidt at NASA says global warming doubled since 2012, during the Michael Mann hiatus and remarkably concurring with Obama's second term in office.

Here's the graph used by Heller to illustrate this egregious doubling of warming.

Wood For Trees

I've no idea what Heller means by doubling the warming, and I doubt NASA made such a claim. If he means the anomaly has doubled since 2012, that would be true if you only consider the trend line, but it's only doubling relative to the chosen base line. If he means the rate of warming has doubled he'd need to say what rate he was comparing it with. The rate of warming since 2012 is far more than twice the overall warming rate. But all of this is irrelevant when you consider we are only talking about four and a half years!

But the real problem here is the way Heller uses this brief period of rapid warming to imply NASA's data is fraudulent as it doesn't agree with the claimed slowdown. Logically there is no contradiction with a slower rate of warming between 2000 and 2014, and a rapid rate of warming between 2012 and 2016, as this graph illustrates.

Wood For Trees

But the stupidest part of this claim is that he doesn't check the claim that NASA the rapid warming shown by NASA by comparing it with other data sets. The rate of warming NASA shows since 2012 is indeed staggering, 10.2 °C / Century. This would be very alarming if it wasn't for the fact that it's only for a very short time and mostly caused by ending with an El Niñ'o. But every other data set you look at shows very similar levels of warming - if NASA is wrong so are all the others. And by others I include the supposidly reliable RSS - RSS version 3.3 shows a warming rate of 9.7 °C / Century since 2012 - almost identical to NASA.

Wood For Trees

If, as Heller claims, NASA's warming since 2012 contradicts the claim that there was a slowdown since 2000, then by his own logic the rapid warming shown by RSS since 2012 contradicts Heller's own claim that there was no warming in the satellite data since 2000.

Either Heller never bothered to check his claims by comparing other data, or more likely he did check but found the results inconvenient and decided to ignore it.