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Why IPCC Climate Forecasts Are So Dodgy

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This is the fourth in a series of articles on the IPCC’s AR6 WG1 report. –CCD ed.

Margaret Thatcher helped create the United Nations Intergovernmental Panel on Climate Change (IPCC) in 1988. As an Oxford-trained chemist, she understood scientific principles and was concerned that we “… do not live at the expense of future generations.”

By 2002, the Iron Lady turned against global warming extremism by stating in her book Statecraft: Strategies for a Changing World, “What is far more apparent is that the usual suspects on the left have been exaggerating the dangers and simplifying solutions in order to press their agenda…” [bold, links added]

Thatcher’s comments of exaggeration and simplification were a prescient critique of the IPCC report Climate Change 2021: The Physical Sciences Basis.

The IPCC uses computer simulations to predict climate dangers and test solutions. An important step in the computer simulation of a real-world physical process is making sure the simulator can replicate the known history of that physical process.

If a computer model can accurately replicate a significant history of a known process, called hindcasting, it lends credibility that the correct equations are being used and will be able to predict future events.

In the Summary for Policymakers section of the subject report, the IPCC claims to have made a lengthy and accurate history match of observed global warming.

They seek to assure the reader that the models they used are able to predict future climate change under different CO2 emissions scenarios.

Except it seems the reverse has happened, the claimed observed global warming history used by the IPCC appears to have been forced to match the computer simulations.

It’s dodgy science when our global warming history gets changed to match the IPCC simulations.

Figure SPM.5 Panel (a) of the subject report (below) shows the IPCC’s observed global warming from 1850 to 2020 on the left map and compares it to the IPCC computer simulation on the right map. It appears to be almost an exact history match.

For clarity, measured global warming on the observed map has been statistically adjusted to 1°C to compare to a simulated outcome of 1°C.

The white area near Antarctica indicates insufficient data history and the blue area south of Greenland indicates observed but unquantified cooling that the IPCC does not accept, deeming it as having “out-of-bound values.”

According to the caption, the highlight of this comparison of observed to simulated maps is that “Across most regions, observed and simulated patterns are consistent.”

Figure SPM.5 Panel (a) does not tell us when this global warming occurred; for that, we will have to refer to Figure SPM.1 Panel (b) in the same report (not reproduced here).

It indicates that of the total measured global warming of approximately 1.2°C, about 0.8°C occurred after 1980. Stated another way, two-thirds of the global warming in the last 170 years occurred from 1980 to 2020, according to the IPCC.

In 1979, satellites came into service with reliable instruments to detect the air temperature of the lower troposphere (where we live).

In contrast to what the IPCC’s Figure SPM.1 Panel (b) indicates, the satellites have measured only 0.5°C of global warming from 1980 to 2020, as seen in the graph below from the University of Alabama at Hunstville (image courtesy

The satellite data results in 0.13°C of warming per decade, while the IPCC measured data results in 0.2°C of warming per decade. That’s 60 percent higher global warming over the same 40-year period.

The database the IPCC used in their observed map is from Berkeley Earth and was compiled from air surface temperatures on land and water surface temperatures from the oceans.

Berkeley Earth reported that with this database they had to consider:

  • Data collection methods from multiple sources
  • Poor station quality
  • The urban heat island effect (where cities heat up the air)
  • Merging land temperature data with sea surface temperature data
  • That often no data was collected for 40 percent of the ocean area (oceans cover 71 percent of the planet)

Compare this to satellites predominately from the National Oceanic and Atmospheric Administration that have high-precision instruments, survey almost total and continuous coverage of the Earth, measure air temperature only, and are independently verified by weather balloon thermometers.

A reasonable response to having two respected but significantly different databases would be to run the simulations with both datasets to get a range of possible outcomes, much like the IPCC already does with different CO2 emission scenarios.

This wasn’t done; only the warmer and less precise Berkeley Earth database was used.

Disturbingly, the fact that satellites measured significantly less warming is not the biggest problem with the IPCC’s history match.

Let’s examine the satellite data map below (courtesy Global Temperature Report: The University of Alabama in Huntsville []):

The biggest problem with the IPCC history match is that the satellite-measured net-global warming consists of regions of warming partially offset by regions of cooling.

As of February 2022, compared to a 30-year average the North Atlantic and parts of Canada are cooler by 3.5°C to 4.5°C (this includes the cooling dismissed on the IPCC observed map) and Central Asia is cooler by 2.5°C to 3.5°C.

The North Pacific is warmer by 2.5°C and Siberia by 3.5°C. The temperature difference between maximum warming and cooling is 8°C, a contrast 16 times greater than the overall 0.5°C warming detected by the satellites in the same period.

Very large areas of the globe have no temperature change compared to the long-term average.

The IPCC’s observed global warming map and the simulation map for 1°C on Figure SPM.5 Panel (a) indicate relatively uniform warming in the tropics, with slightly elevated warming in the polar regions.

It has a maximum temperature contrast of about 1.5°C (again, the cooling region below Greenland was rejected), a contrast which is only 1.5 times greater than the overall warming.

Recall that the IPCC’s observed global warming map based on the Berkeley Earth data is condensed to 1°C and begins in 1850; the satellite data begins in 1980 and has only measured 0.5°C warming since then.

Perhaps the mapped patterns of warming and cooling are different because the magnitude and timing of the warming are different. There is a way we can check that.

Here is the Berkeley Earth (What’s New – Berkeley Earth) representation of their own dataset incorporating 1.2°C warming from 1850 to 2020:

Across most regions, the patterns of 170 years of global warming as per the Berkeley Earth database are very similar to the 40-year satellite database.

They both indicate a chaotic climate system with warming and cooling over both land and water simultaneously, with the overall result being net warming.

Note the maximum temperature contrasts between warming and cooling regions on the Berkely Earth map are about 10°C, eight times greater than the overall net global warming.

The observed global warming map used by the IPCC is not even close to the observed map produced independently by Berkeley Earth using the same database.

Not only does this undermine the IPCC history match, but it also substantiates that the satellite data should not be ignored.

The findings are clear: our planet’s climate is much more chaotic and much more volatile than the IPCC observes or predicts.

The observed map in Figure SPM.5 Panel (a) was intended to build confidence in the forecasting ability of the IPCC climate simulations; in actuality, it diminishes confidence. How did the IPCC come up with it using the Berkeley Earth data?

Twenty years ago, Margaret Thatcher was concerned about the global warming movement she helped create because she recognized there was already an exaggeration of the dangers and a simplification of the solutions.

Today the failure to conduct a sensitivity analysis of the current rate of significantly lower global warming detected by four decades of precision satellite measurements adds to the concern of exaggeration.

The IPCC computer simulations of global warming achieved a history match to an overly simplistic map of global warming that is in conflict with the quoted database. That should instill in all of us serious doubts about the forecasting abilities of those simulations.

The Iron Lady also said of the global warming alarmists that “…there was madness in their method…” I think she meant the science was dodgy.

Ron Barmby is a Professional Engineer with a Bachelor’s and Master’s degree, whose 40+ year career in the energy sector has taken him to over 40 countries on five continents. His book “Sunlight on Climate Change: A Heretic’s Guide to Global Climate Hysteria” (AmazonBarnes & Noble) explains in understandable terms the science of how both natural and human-caused global warming work. Over two dozen other articles and presentations can be found at

Permission to use all or part of this article is given freely to all, provided that any such use is accompanied by author attribution and a link to the original article.

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