NASA - Cooling the Past and Warming the Present

Jan 04, 2015

I’ve done a lot of stationary and non-stationary time series modeling throughout my professional career. Millions of dollars were staked on my getting it right. Historical temperature data is non-stationary time series data.

I’ve been following a recent heated debate amongst leading climatologists about NASA adjusting the official GISS historical temperature record in the latest release of the dataset. NASA’s claim is they’ve changed/added an algorithm to better account for TOBS (Time of Observation) bias.

I have a problem with that explanation. The temperature dataset is of such high frequency that any variability in TOBS would be equally distributed such that it would be statistically insignificant and thus, requires no adjustment.

Why am I making these points? Because NASA's adjustments have cooled the past and warmed the present through a series of manual, after the fact, adjustments to the data. Shown below is a graph of the historical temperatures in NASA’s 1981 GISS dataset (the black line). Overlaid on the graph is their most recent GISS dataset (the red line). The past has been cooled by 0.3C just through manual adjustments of the new dataset.


Okay, so now we know NASA has been adjusting the past making it colder, at least through 1981. But what about adjustments since 1981 through to the present?

The 1981 GISS dataset can’t help us make a valid comparison as it doesn’t extend to the present. However, it happens that in 1979, we started launching some of the highest precision thermometers available to science into space on climate satellites to measure global temperatures. Additionally, we’ve been sending extremely accurate radiosondes (thermometers on balloons) into the atmosphere. The radiosondes agree remarkably well with the satellites so I’ll stick to using the official RSS satellite temperature dataset to make the comparison.

And here it is.

GISS Comparison

The green line is the latest official RSS historical satellite temperature dataset, current to 2013.

Houston, we have a problem!!! There’s a divergence of 0.38C between the RSS dataset and the GISS dataset.

Here’s where things get a bit controversial. It is was generally claimed that man’s contribution to global warming over the past century has been ~0.7C deg. Lets do some simple math. From the 1920’s though 1980, there has been -0.3C in downward adjustments. From 1980 forward there’s been a whopping +0.38C in upward adjustments. Add them up and what do you get? +0.68C warming.

What conclusion could be made from this? Most of the global warming claimed by GISS over the past century truly is man made. Only, its all in the adjustments made to the GISS data, not in the actual thermometer measurements themselves. That's one concusion that could be made but is it valid? No, but it is a conclusion many will make because the extent of adjustments open the dataset to it being made.

What I’m saying is when a dataset can account for most, if not all of man’s contribution to global warming with data adjustments alone, the adjustments greatly exceed the variance of the underlying data and diverges by the same degree of adjustment from other higher precision datasets and even from the previous version of the same dataset, there’s a problem that deserves skeptical inquiry.

Here’s another problem I see in the adjustments. It is presumed that the accuracy of thermometers in the 1800’s are not as good as today’s. I would agree with that. However the adjustments made in the new GISS dataset are significantly larger for the past 20 years than any time in the past. That makes no sense. Technology has improved so the need for adjustments should have decreased, not increased.

In a nutshell, what I’m saying is the latest release of GISS is problematic. To visualize the problem, here is a model run of GISS along with other official datasets.


GISS is in red. It is clearly running outside of the pack - a whole +0.4C warmer than the others. Either GISS is right and the other official datasets wrong or GISS is wrong. I take the more reasonable position that GISS is wrong and any claims made from it, like 2014 being the hottest year in recorded history, should be suspect.

All this divergence between the ground based thermometer record and the much more accurate satellite record begs an even more profound question… If the satellite measurements are magnitudes more accurate and not subject to TOBS bias, why does the United Nations International Panel on Climate Change (IPCC) prefer to use the less accurate and arguably problematic GISS dataset? Could it be that the satellites don’t support the catastrophic climate sensitivity espoused by the IPCC?

And allow me to share some parting comments from leading climatologists regarding the latest release of GISS and NASA's claims that 2014 was the hottest year on record:

Climatologist Dr. Roy Spencer (U.S. Science Team leader for the Advanced Microwave Scanning Radiometer flying on NASA’s Aqua satellite): "2014 won’t be the warmest global-average year on record...if for no other reason than this: thermometers cannot measure global averages — only satellites can. The satellite instruments measure nearly every cubic kilometer – hell, every cubic inch — of the lower atmosphere on a daily basis.

You can travel hundreds if not thousands of kilometers without finding a thermometer nearby. The thermometer network is made up of a patchwork of non-research quality instruments that were never made to monitor long-term temperature changes to tenths or hundredths of a degree, and the huge data voids around the world are either ignored or in-filled with fictitious data.'

Climatologist Dr. Pat Michaels: ‘Is 58.46° then distinguishable from 58.45°? In a word, ‘NO.’

Climate Physicist Dr. Lubos Motl: ‘Please laugh out loud when someone will be telling you that it was the warmest year’

Climatologist Dr. Judith Curry, former chair of the school of earth and atmospheric sciences at Georgia Institute of Technology and climate advisor to Congress: “The ‘warmest year’ is noticeably missing in the satellite data sets of lower atmospheric temperatures...”

Climatologist Dr. John Christy, professor of atmospheric sciences, University of Alabama-Huntsville (and lead scientist for the UAH satellite dataset):"Satellites do not agree with “warmest year” claims.

Climatologist Dr. Roger Pielke Sr., professor of atmospheric science, Colorado State University: “There remain significant uncertainties in the accuracy of the land portion of the surface temperature data, where we have found a significant warm bias. Thus, the reported global average surface temperature anomaly is also too warm.”

Climate Astrophysicist Dr. Dr David Whitehouse: “talk of a record is scientifically and statistically meaningless.’ “The addition of 2014 global temperature data confirms that the post-1997 standstill seen in global annual average surface temperature has continued.”

[Edit Jan. 5, 2015]I realized the date for the the red running mean in my top graph was wrong. I changed it from 2010 to 2011. It now agrees with the lower graph. I also corrected the meta-tag for the title of this page, which got the title backwards.

I have been asked what smoothing I used for the line series in the graphs. I used a five year smoothing. I used five years because it is what Dr. Hansen used in his 1981 presentation of the GISS dataset. I wanted my comparisons to be apples with apples. There is a slight gap between the GISS 1981 and RSS series in the lower graph. This is not an error but rather how smoothing models work - they truncate a small portion of the data. The bottom graph uses a 26 month smoothing.

A good friend who read my article and who is an educator I hold much respect for, called to my attention that I seem to be claiming that all of global warming is due to data adjustments, which is not at all my position. I have ammended this article to more clearly state my conclusion.

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