Satellites show no warming for twenty years – but fake NASA surface temperatures show lots of warming.
With this graph from Wood For Trees to illustrate the point.
Tony Heller's graph showing no warming in UAH 6 data, since 1997.
It's true that NASA's data shows lots of warming, but is it really true that satellites show no warming.
Lets check this using the same data.
Graph showing some warming in UAH 6 data, since 1997.
Wood For Trees
UAH definitely shows some warming, not the flat line Heller's graph shows.
Both graphs use the same data, both show the temperatures using a 5 year rolling average, but whereas Heller calculates the trend line using the averaged data, I calculate it correctly -
using the monthly data.
Using smoothed data is not the way to calculate a regression.
In particular it reduces the influence of the start and end points of the period.
In this case the first and last 2.5 years have less importance in determining the trend line than the middle 15 years, with the influence reducing as you move close to the start and finish.
The most recent 30 months were quite a bit warmer than the first 30 months, so reducing their importance is sufficient to turn an overall warming trend into a slight negative trend.
This explains why the true linear regression looks out of place when compared with the 60 month rolling average.
If we look 12 month rolling averages the picture becomes clearer.
To put some figures on the above, since the start if 1997, UAH 6 has been warming at the rate of 0.64 °C / century, compared to GISS's rate of 1.72 °C / century.
The old UAH 5.6 has been warming at the rate of 1.60 °C / century.
Tony Heller (aka Steve Goddard) has one main claim on his Deplorable Climate Science site,
that climate scientists at NASA and NOAA are criminals who are perpetuating the biggest fraud in science history, by adjusting their data sets.
Surface data was nearly infallible 40 years ago, and any changes since then have moved us further from reality.
It is not possible, in his view, that changes might represent honest efforts to improve the data or to remove past errors.
For this to be true every organization producing surface temperature records must be part of this conspiracy,
as must the RSS satellite data now that version 4 is out showing similar levels of warming.
Even Roy Spencer and John Christy producers of the UAH data were part of this fraud, when they were promoting UAH version 5.6 showing similar levels of warming to surface data.
Indeed, Heller accuses them of fraud here, couple of years ago Cooling the Past at UAH.
An Example
A recent blog post by Heller had a claim of adjustments that caught my eye
No Global Warming For 25 Years.
He starts by claiming there's been no warming for 25 years, before insisting that as NASA's data shows warming over 25 years they must be fraudulent.
Then he makes a specific claim that NASA made an adjustment in the month following Trump's election.
The first claim is obviously wrong, the second turned out to be correct, but Heller gets the effect completely wrong.
No Warming?
The claim that there's been no warming for 25 years is bogus.
Heller's talking about RSS 3.3 and actually uses a 26 and a half year period, starting mid-1990.
Here's a graph showing RSS 3.3 over that period:
RSS 3.3 has been warming at the rate of 1.36 °C / century over Heller's period, and that trend is statistically significant.
His claim that NASA show 0.5 °C more warming than RSS 3.3 is therefore exaggerated.
NASA's rate of warming over the same period, is 1.96 °C / century.
Over the past 26.5 years RSS 3.3 has warmed 0.36 °C and NASA 0.52 °C.
The difference between NASA and RSS is 0.16 °C, not the 0.5 °C Heller claims.
The Adjustments
Comparing NASA's data and RSS, Heller says:
Agreement between the satellite and surface temperature data was good until about the year 2000,
but since then NASA has been continuously tampering with their data to create
the impression of non-existent warming.
Just during the month after the election NASA altered their data even further.
He justifies that final claim with this graph.
Graph from The Deplorable Climate Science Blog
The first thing to note is that he's shifted to land only data - ignoring the 70% of the globe that is ocean.
This is a problem as it will exaggerate the significance of any adjustments made to the land data.
Heller's graph shows a comparison between the December and November NASA data, using a 5 year average, with December being around 0.02 °C warmer.
His graph only goes back to the end of the 20th century, so it's not possible to see if this has an effect on the overall warming starting, say, from the mid 70s.
I checked the changes for myself using old data downloaded from the Wayback Machine.
One slight problem is that it isn't entirely clear which months Heller is comparing.
December could mean the data released in December (which would go up to November), or it could mean the data released in January which includes the results for December.
Therefore I looked at the last 3 releases, labelled October, November and December in my graph.
The labels refer to the month the data goes up to.
For example, December is the most up to date version, released in January with results up to December.
Here's my version of Heller's graph - showing a 60 month rolling average for each set.
5 year rolling mean anomalies for three different versions of GISTEMP land data.
This shows Heller is partly correct, there have been adjustments in both of the last two months.
But it also shows Heller's main claim is wrong.
His graph shows the December data is warmer than November's.
But mine shows the reverse -
November is cooler than October,
December is cooler than November.
But how significant are these changes?
Here's the graph extended back to the mid-20th century.
5 year rolling mean anomalies for three different versions of GISTEMP land data.
The adjustments are reversed in the mid-70s; December is slightly warmer, which means the rate of warming since then will have been reduced.
But the graph also shows that these adjustments are not that large.
The effect on the warming rate since 1975 (up to October 2017) are:
Data Set
Rate in °C / century
October 2016
2.23
November 2016
2.18
December 2016
2.16
Over the last two months, NASA's tampering has reduced the rate of warming by 0.07 °C per century.
This is pretty trivial to start with, but remember this is land only data, and only about 30% of the globe.
Here's what the adjustments look like when you look at land and ocean.
5 year rolling mean anomalies for three different versions of GISTEMP global data.
The adjustments are much smaller,
and when you look at a longer time scale -
5 year rolling mean anomalies for three different versions of GISTEMP global data.
they virtually disappear.
For global data the rate of change since 1975 is nearly identical for each set, changing from 1.83 °C / century in October, to 1.82 °C / century in December.
Conclusion
None of this is to suggest Tony Heller is being fraudulent in claiming NASA increased warming over the last few months,
when they actually reduced it.
It's entirely possible this was an honest mistake on Heller's part, though it does suggest some degree of confirmation bias -
he sees a difference and assumes the direction that confirms his prejudices.
The main point, is that it's easy to focus on minor changes that have little impact on the bigger picture,
and to assume that changes to the data are fraudulent, rather than an honest attempt to iprove the quality of the data.
There's a lot more in Heller's post, but it all tends to be on the same theme - the assumption that adjustments are fraud.
One final point though - whilst Heller gives the impression that all these changes are criminal,
you can find all the major changes plotted on NASA's own site, here.
So, the question is, what sort of devious secret cable of evil scientists put all the evidence exposing their criminal activity on their own website?
