Climate Revisionism 101 : “We Have To Get Rid Of The Medieval Warm Period”

WHEN you are a man-made global warming alarmist prosecuting your case as “unprecedented”, you need to make sure that no recent climate era was as warm or warmer than the present, even if that means having to rewrite the past to fit your theory.

THE Medieval Warm Period, also known as the Medieval Climate Optimum (for obvious reasons) existed a short time ago in the climate record, from c. 950 to c. 1250., and has remained a thorn in the side for modern “global warming” catastrophists…

IN the 1990 IPCC report, the Medieval Warm Period was much warmer than the late 19th century:

THE IPCC’s 1990 report dives deeper into the reality of the Medieval Warm Period and provides an insight into the cause of these warming periods:

“This period of widespread warmth is notable in that there is no evidence that it was accompanied by an increase of greenhouse gases.

IPCC WG1 Report 1990 (p202)

BY the 2001 IPCC report, the Medieval Warm period disappeared and became much cooler than the late 20th century:


BY pure coincidence, in the year 1995 the IPCC made a decision to make the Medieval Warm Period disappear:

Screen Shot 2013-11-27 at , November 27, 2.30.47 PM

YOUTUBE clip of Dr David Deming’s US Senate testimony on the “disappearance” of the Medieval Warm Period (see 01m:50s) :

Video of Dr David Deming’s statement to the U.S. Senate Committee on Environment & Public Works on December 6, 2006. Dr Deming reveals that in 1995 a leading scientist emailed him saying “We have to get rid of the Medieval Warm Period”. A few years later, Michael Mann and the IPCC did just that by publishing the now throughly discredited hockey stick graph.

IN case you missed it…

“I had another interesting experience around the time my paper in Science was published. I received an astonishing email from a major researcher in the area of climate change. He said, “We have to get rid of the Medieval Warm Period.””

The existence of the MWP had been recognized in the scientific literature for decades. But now it was a major embarrassment to those maintaining that the 20th century warming was truly anomalous. It had to be “gotten rid of.””

Statement of Dr. David Deming | U.S. Senate Committee


ACCORDING to ‘science’, the Medieval Warm Period was indeed ‘global’ and was as warm, if not warmer, than today’s current warming period…

CLICK here for interactive map




See also :


via @BigJoeBastardi | Twitter


MWP related :

Peer Review studies that show the Medieval Warm Period was indeed global and as warm, if not warmer than todays temps…

Climatism related :



“THE PAUSE” Lives On : Global Temperatures Continue To Cool Despite Record And Rising CO2 Emissions


GLOBAL temps continue their cooling trend, rebounding off the 2015/16 Super El Niño – the strongest since accurate measurements began, caused by surface waters in the Pacific Ocean, west of Central America rising up to 3C warmer than usual.

THE latest UAH V6.0 February anomaly of +0.20 brings temperatures back to the levels they were at after the 1998 El Niño.

UAH Feb data and results here…





NASA’s MSU satellite measurement systems, generate the RSS and UAH datasets, which measure the average temperature of every cubic inch of the lower atmosphere, the exact place where global warming theory is meant to occur.

BEFORE 2016, UAH and RSS both tracked closely showing very little warming in their data sets which led to the identification and validation of “the pause” in global warming which has since become the subject of much research and debate in peer-reviewed scientific journals.

From the RSS website:

HOWEVER, by 2016, Carl Mears, who is the chief scientist for RSS (Remote Sensing Systems) and who has used the pejorative “denialist” in various correspondence, decided that “the pause” was not a good look for the global warming narrative so RSS was massively adjusted upwards, conveniently eliminating “the pause” in the RSS dataset.

Mears’ objectivity towards the business of global temperature data collection and reporting can be found in his commentary on his website:

MEARS then published a paper claiming that new and improved adjustments have “found” that missing warming.

Mears, C., and F. Wentz, 2016: Sensitivity of satellite-derived tropospheric
temperature trends to the diurnal cycle adjustment. J. Climate. doi:10.1175/JCLID-
15-0744.1, in press.

THE result…
Differences between the old version and new version of RSS:



(Data and research via WUWT)


UAH is the satellite data set featured in this post and is jointly run by Dr. John R. Christy –  Distinguished Professor of Atmospheric Science and Director of the Earth System Science Center at The University of Alabama in Huntsville. And Roy Spencer Ph.D. Principal Research Scientist at the University of Alabama in Huntsville.

Spencer commentary on the divergence between RSS and UAH post “adjustment”:

“We have a paper in peer review with extensive satellite dataset comparisons to many balloon datasets and reanalyses. These show that RSS diverges from these and from UAH, showing more warming than the other datasets between 1990 and 2002 – a key period with two older MSU sensors both of which showed signs of spurious warming not yet addressed by RSS. I suspect the next chapter in this saga is that the remaining radiosonde datasets that still do not show substantial warming will be the next to be “adjusted” upward.

The bottom line is that we still trust our methodology. But no satellite dataset is perfect, there are uncertainties in all of the adjustments, as well as legitimate differences of opinion regarding how they should be handled.

Also, as mentioned at the outset, both RSS and UAH lower tropospheric trends are considerably below the average trends from the climate models.

And that is the most important point to be made.”

Comments on the New RSS Lower Tropospheric Temperature Dataset « Roy Spencer, PhD

(Climatism bolds)



THIS epic twitter conversation between NASA GISS’ chief climate commissar Gavin Schmidt and @7Kiwi captured an epic admission as to the spurious nature of the highly upwardly ‘adjusted’ NASA land-ocean temperature data set, that leads to the huge and widely recognised divergence between satellite observations, climate models and NASA’s GISS temp…


A translation (square brackets) of Gavin’s admissions just for fun . Though many truths in it…

NASA and NOAA’s preferred surface-based thermometers measure “different parts of the system [UHI affected parking lots, asphalt heat sinks, AC exhaust air vents], different signal to noise ratio [we bias toward warm stations], different structural uncertainty [we ‘homogenise’ the data set to cool the past and warm the present to fit the global warming narrative].”NASA GISS Gavin Schmidt’s admission about the satellite record versus the surface temperature record

More info on NASA GISTEMP: Data.GISS: GISS Surface Temperature Analysis (GISTEMP)


IT’S not difficult to see why the NASA data set is the preferred go-to for global warming activists, mainstream media, the UN IPCC and politicians seeking to implement draconian climate policy on their citizenry…

Screen Shot 2018-03-02 at 8.21.43 am.png

Land-ocean temperature index, 1880 to present, with base period 1951-1980. The solid black line is the global annual mean and the solid red line is the five-year lowess smooth. The blue uncertainty bars (95% confidence limit) account only for incomplete spatial sampling. [This is an update of Fig. 9a inHansen et al. (2010).]

“The Pause” is well and truly wiped from the record, with vengeance!

C/w UAH satellite global temp data:



NASA has doubled global warming since 2001:


NASA make up make up record temperatures in countries where they have no thermometer data. NOAA’s current data in Africa and much of the rest of the world is fake:


NASA has massively altered their US temperature data since 1999, to make a 1930-2000 cooling trend disappear:

SEE more extreme examples of NASA / NOAA temperature data fraud at Tony Heller’s superb resource: The Deplorable Climate Science Blog | “Science is the belief in the ignorance of the experts” – Richard Feynman


GOOD READ : Satellites / Thermometers

Measuring global temperatures: Satellites or thermometers? 


by Dr. Roy Spencer

The University of Alabama in Huntsville

The official global temperature numbers are in, and NOAA and NASA have decided that 2015 was the warmest year on record. Based mostly upon surface Dr_-Roy-Spencer-178x300thermometers, the official pronouncement ignores the other two primary ways of measuring global air temperatures, satellites and radiosondes (weather balloons).

The fact that those ignored temperature datasets suggest little or no warming for about 18 years now, it is worth outlining the primary differences between these three measurement systems.

Three Ways to Measure Global Temperatures

The primary ways to monitor global average air temperatures are surface based thermometers (since the late 1800s), radiosondes (weather balloons, since about the 1950s), and satellites measuring microwave emissions (since 1979). Other technologies, such as GPS satellite based methods have limited record length and have not yet gained wide acceptance for accuracy.

While the thermometers measure near-surface temperature, the satellites and radiosondes measure the average temperature of a deep layer of the lower atmosphere. Based upon our understanding of how the atmosphere works, the deep layer temperatures are supposed to warm (and cool) somewhat more strongly than the surface temperatures. In other words, variations in global average temperature are expected to be magnified with height, say through the lowest 10 km of atmosphere. We indeed see this during warm El Nino years (like 2015) and cool La Nina years.

The satellite record is the shortest, and since most warming has occurred since the 1970s anyway we often talk about temperature trends since 1979 so that we can compare all three datasets over a common period.

Temperatures of the deep ocean, which I will not address in detail, have warmed by amounts so small — hundredths of a degree — that it is debatable whether they are accurate enough to be of much use. Sea surface temperatures, also indicating modest warming in recent decades, involve an entirely new set of problems, with rather sparse sampling by a mixture of bucket temperatures from many years ago, to newer ship engine intake temperatures, buoys, and since the early 1980s infrared satellite measurements.

How Much Warming?

Since 1979, it is generally accepted that the satellites and radiosondes measure 50% less of a warming trend than the surface thermometer data do, rather than 30-50% greater warming trend that theory predicts for warming aloft versus at the surface.

This is a substantial disagreement.

Why the Disagreement?

There are different possibilities for the disagreement:

1) Surface thermometer analyses are spuriously overestimating the true temperature trend
2) Satellites and radiosondes are spuriously underestimating the true temperature trend
3) All data are largely correct, and are telling us something new about how the climate system operates under long-term warming.

First let’s look at the fundamental basis for each measurement.

All Temperature Measurements are “Indirect”

Roughly speaking, “temperature” is a measure of the kinetic energy of motion of molecules in air.

Unfortunately, we do not have an easy way to directly measure that kinetic energy of motion.

Instead, many years ago, mercury-in-glass or alcohol-in-glass thermometers were commonly used, where the thermal expansion of a column of liquid in response to temperature was estimated by eye. These measurements have now largely been replaced with thermistors, which measure the resistance to the flow of electricity, which is also temperature-dependent.

Such measurements are just for the air immediately surrounding the thermometer, and as we all know, local sources of heat (a wall, pavement, air conditioning or heating equipment, etc.) can and do affect the measurements made by the thermometer. It has been demonstrated many times that urban locations have higher temperatures than rural locations, and such spurious heat influences are difficult to eliminate entirely, since we tend to place thermometers where people live.

Radiosondes also use a thermistor, which is usually checked against a separate thermometer just before weather balloon launch. As the weather balloon carries the thermistor up through the atmosphere, it is immune from ground-based sources of contamination, but it still has various errors due to sunlight heating and infrared cooling which are minimized through radiosonde enclosure design. Radiosondes are much fewer in number, generally making hundreds of point measurements around the world each day, rather than many thousands of measurements that thermometers make.

Satellite microwave radiometers are the fewest in number, only a dozen or so, but each one is transported by its own satellite to continuously measure virtually the entire earth each day. Each individual measurement represents the average temperature of a volume of the lower atmosphere about 50 km in diameter and about 10 km deep, which is about 25,000 cubic kilometers of air. About 20 of those measurements are made every second as the satellite travels and the instrument scans across the Earth.

The satellite measurement itself is “radiative”: the level of microwave emission by oxygen in the atmosphere is measured and compared to that from a warm calibration target on the satellite (whose temperature is monitored with several highly accurate platinum resistance thermometers), and a cold calibration view of the cosmic background radiation from space, assumed to be about 3 Kelvin (close to absolute zero temperature). A less sophisticated (infrared) radiation temperature measurement is made with the medical thermometer you place in your ear.

So, Which System is Better?

The satellites have the advantage of measuring virtually the whole Earth every day with the same instruments, which are then checked against each other. But since there are very small differences between the instruments, which can change slightly over time, adjustments must be made.

Thermometers have the advantage of being much greater in number, but with potentially large long-term spurious warming effects depending on how each thermometer’s local environment has changed with the addition of manmade objects and structures.

Virtually all thermometer measurements require adjustments of some sort, simply because with the exception of a few thermometer sites, there has not been a single, unaltered instrument measuring the same place for 30+ years without a change in its environment. When such rare thermometers were identified in a recent study of the U.S., it was found that by comparison the official U.S. warming trends were exaggerated by close to 60%. Thus, the current official NOAA adjustment procedures appear to force the good data to match the bad data, rather than the other way around. Whether such problem exist with other countries data remains to be seen.

Changes in radiosonde design and software have occurred over the years, making some adjustments necessary to the raw data.

For the satellites, orbital decay of the satellites requires an adjustment of the “lower tropospheric” (LT) temperatures, which is well understood and quite accurate, depending only upon geometry and the average rate of temperature decrease with altitude. But the orbital decay also causes the satellites to slowly drift in the time of day they observe. This “diurnal drift” adjustment is less certain. Significantly, very different procedures for this adjustment have led to almost identical results between the satellite datasets produced by UAH (The University of Alabama in Huntsville) and RSS (Remote Sensing Systems, Santa Rosa, California).

The fact that the satellites and radiosondes – two very different types of measurement system — tend to agree with each other gives us somewhat more confidence in their result that warming has been much less than predicted by climate models. But even the thermometers indicate less warming than the models, just with less of a discrepancy.

And this is probably the most important issue…that no matter which temperature monitoring method we use, the climate models that global warming policies are based upon have been, on average, warming faster than all of our temperature observation systems.

I do believe “global warming” has occurred, but (1) it is weaker than expected, based upon independent satellite and weather balloon measurements; (2) it has been overestimated with poorly adjusted surface-based thermometers; (3) it has a substantial natural component; and (4) it is likely to be more beneficial to life on Earth than harmful.

About the Author: Dr. Roy Spencer

Roy W. Spencer is a Principal Research Scientist at the University of Alabama in Huntsville. He received his Ph.D. in Meteorology from the University of Wisconsin in 1981. As Senior Scientist for Climate Studies at NASA’s Marshall Space Flight Center, Dr. Spencer previously directed research into the development and application of satellite passive microwave remote sensing techniques for measuring global temperature, water vapor, and precipitation. He is co-developer of the original satellite method for precision monitoring of global temperatures from Earth-orbiting satellites. Dr. Spencer also serves as U.S. Team Leader for the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) flying on NASA’s Terra satellite. He has authored numerous research articles in scientific journals, and has provided congressional testimony several times on the subject of global warming.


“The Pause” related :

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“HOTTEST YEAR EVAH” Claims Tell Us More About Global Warming PR Than Actual Science

heat wave in the city and hand showing thermometer



THE “Hottest Year Ever” meme is just one in a long line of marketing techniques used by Climate Crisis Inc. to make you believe the world is burning up.

HOW much of these claims are scientific, versus, pure-propaganda designed to heighten alarm on a publicly waning issue – catastrophic anthropogenic global warming (CAGW)? A *theory* whose veracity is becoming increasingly questioned by contradictory science, real-world observations and growing public and media awareness of the disturbing trend of temperature data manipulation by our most ‘trusted’ scientific agencies.

THE brilliant Paul Driessen nails it in a foreword to an excellent post on WUWT by Dr. Tim Ball and Tom Harris – “Overheated claims on temperature records

Overheated claims on global temperature records

Foreword by Paul Dreissen

Over and over, we are confronted with claims that last month or last year was “the warmest on record.” Each claim is accompanied by dire warnings that the alleged new records portend “unprecedented” chaos for wildlife, humans and planet.

Virtually never do these scary press releases mention:

  • That the supposed change is mere hundredths of a degree higher than previous measurements.
  • Never do they admit that the margin of error in these measurements is far greater than the supposed increase.
  • Never do they suggest that a little more warmth would be infinitely better than a colder world, with less arable land and shorter growing seasons.
  • And most certainly, never do they admit to the massive deficiencies in the system that supposedly tracks Earth’s temperature … and
  • Always blames any increases on humans and fossil fuels.

This article by Dr. Tim Ball and Tom Harris points out all these highly relevant but often (deliberately) ignored realities.

(Climatism bullets/bolds)

READ the excellent Ball / Harris article here…


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The “HOTTEST YEAR EVAH” Meme Exposed


AS the old saying goes “Sunlight is said to be the best of disinfectants“. One man who has been tireless and paid-less (sic) in the pursuit of exposing the blatant and unequivocal  global temperature data fraud, executed by taxpayer funded government scientific agencies worldwide, has been Tony Heller aka Steve Goddard.

THERE are literally thousands upon thousands of mind-blowing examples of temperature data manipulation/fraud carried out in-plain-sight by climate activist agencies namely – NOAA, NASA, BoM, Met Office UK – who happen to be the literal gate-keepers of global temperature. They do this simply to make you believe that the climate is warming catastrophically thanks to your carbon dioxide (energy) emissions.

THE blink giff included in this post is really all one needs to know about how climate scientists literally “change the data to fit the theory” – a quote linked to Hungarian Marxist Georg Lukacs in his ‘Tactics and Ethics’ (1923) though often associated with Albert Einstein as a non-literal quip.

OTHER than driving the climate scare and maintaining taxpayer funding to the tune of $Trillions worldwide, hysterical claims of the “hottest year, month, day ever” tell us far more about global warming climate change marketing than they do about actual ‘science’.


Via Tony Heller’s “The Deplorable Climate Science Blog :

Unambiguous Fraud In The National Climate Assessment

The National Climate Assessment claims unambiguous warming globally and in the US since 1880.


They show a very detailed graph and map which expresses the claimed warming.

All that red looks pretty scary. Red is the color of fire, and it isn’t hard to convince some people that their carbon sins will lead to hell fire.

What they aren’t telling is that their graph and map are fake. They have no idea what global temperatures were in 1880, 1900, 1920, 1940, or in fact the present,  because outside of the US there is very little verifiable data.

As late as 1940, there was almost no daily coverage of South America or Africa.

NOAA’s current data in Africa and much of the rest of the world is still fake. They make up record temperatures in countries where they have no thermometer data.

Real temperatures       Reported temperatures

By their own admission, the ocean data is also fake.

date: Wed Apr 15 14:29:03 2009
from: Phil Jones <> subject: Re: Fwd: Re: contribution to
to: Thomas Crowley <>


The issue Ray alludes to is that in addition to the issue
of many more drifters providing measurements over the last
5-10 years, the measurements are coming in from places where
we didn’t have much ship data in the past. For much of the SH between 40 and 60S the normals are mostly made up as there is very little ship data there.


The only location on Earth with good long term daily temperature data in the US.

Before NOAA tampers with their data, the US shows no warming over the past century.

The lack of US warming wrecks global warming theory, so NOAA and NASA tamper with their own data to create fake warming.


1999 Version       2017 Version

The frequency and coverage of hot weather has plummeted in the US over the past century. The US isn’t getting hotter – afternoons are getting cooler.

The US temperature data is tampered with by NOAA in a massive hockey stick.

Which is designed to bring the data precisely in line with CO2 theory.

NOAA knows perfectly well that the US is not warming.

U.S. Data Since 1895 Fail To Show Warming Trend –

US and global temperatures are constantly being tampered with to cool the past and warm the present.

US tampering :

Global tampering :

1981: Challenge_chapter2.pdf         2001:     current: Fig.A.gif 

2001 version :   2015 version: Fig.A.gif 

All of the claims in the National Climate Assessment about global warming are unsupportable junk science, made largely with fraudulent or imaginary data. Global warming is the biggest scam in science history. It has been thoroughly corrupted by tens of billions of dollars of government money – which fake climate scientists refuse to let go of.

The only thing global and unambiguous in the National Climate Assessment, is the level of junk science and fraud it represents.

Unambiguous Fraud In The National Climate Assessment | The Deplorable Climate Science Blog


Related :

NASA / NOAA Data Fraud Related :

CALIFORNIA Wildfires Are Not Due To Climate Change

Brilliant analysis Tony Heller aka Steve Goddard.
And, not to mention that a homeless encampment cooking fire was responsible for the latest Bel Air fire. Yet, California’s “climate ambulance chaser” in chief, governor Jerry Brown instead blamed “climate change” as a “new normal” … apparently an easier problem to address than the state’s chronic homelessness.

Green Jihad

In this video, author and scientist Tony Heller brilliantly debunks ambulance chasing climate scientists who come out of the woodwork every time there is a natural disaster, like wildfires in California. In fact, burn acreage in the US has plummeted over the past 85 years, as CO2 has increased.

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NOAA Still Falsifying Icelandic Climate History

“THE past was erased, the erasure was forgotten, the lie became the truth.” – George Orwell, 1984


By Paul Homewood

You would be forgiven for thinking that the Iceland Met Office are probably the best people for understanding the history of their own climate.

In 2008, their leading climatologist, Trausti Jonsson, wrote this article:


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In Australia, faulty BoM temperature sensors contribute to “hottest year ever”

“I don’t believe in conspiracies of silence except when it comes to Harvey Weinstein and the Australian Bureau of Meteorology.”

“…the Bureau can give us a hottest winter on record, even when there are record snow dumps in the Alps, and record numbers of frosts on the flats.”

BOMBSHELL report from the ever-persistent pit bull down under, Dr Jennifer Marohasy, exposing yet more fraudulent warming bias from Australia’s corrupt Bureau of Meteorology…

Watts Up With That?

More hot days — or “purpose-designed” temperature sensors at play?

Guest essay by Dr. Jennifer Marohasy, republished from the Australian Spectator with permission from the author.

I don’t believe in conspiracies of silence except when it comes to Harvey Weinstein and the Australian Bureau of Meteorology.

For some time, weather enthusiasts have been noticing rapid temperature fluctuations at the ‘latest observations’ page at the Bureau’s website. For example, Peter Cornish, a retired hydrologist, wrote to the Bureau on 17 December 2012 asking whether the 1.5 degrees Celsius drop in temperature in the space of one minute at Sydney’s Observatory Hill, just the day before, could be a quirk of the new electronic temperature sensors. Ken Stewart, a retired school principal, requested temperature data for Hervey Bay after noticing a 2.1 degrees Celsius temperature change in the space of one minute on 22 February 2017.

In both cases, the Bureau assured…

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