Global warming trend is ‘only one-half of the climate model simulations,’ says new paper
Reason, 27 April 2023
By Ronald Bailey
The latest suite of climate models collectively projects that the average temperature of the global atmosphere should be increasing at the rate of about 0.28–0.29 degrees Celsius per decade. But how do these model projections compare to actual temperature data? It depends.
Let’s first take a look at research using surface thermometer data assembled from weather stations, ocean-going ships, and buoys. The Berkeley Earth team reports that since 1980, the global average temperature is increasing at the rate of 0.19 degrees Celsius per decade. The National Oceanic and Atmospheric Administration (NOAA) finds that the global average temperature has been increasing at the rate of 0.18 degrees Celsius per decade since 1981. NASA’s GISTEMP data set reports an increase of 0.19 degrees Celsius per decade. The U.K.’s Hadley Centre finds the increase is about 0.20 degrees Celsius per decade.
The European Centre for Medium-Range Weather Forecasts reports the global average temperature trend generated by its fifth-generation atmospheric reanalysis (ERA5). Reanalysis is a blend of observations with past short-range weather forecasts rerun with modern weather forecasting models. From 1979 on, the ERA5 calculates that the global average temperature has been increasing at a rate of 0.19 degrees Celsius per decade. The Japan Meteorological Agency’s JRA-55 reanalysis finds the per-decade rate of increase is 0.18 degrees Celsius.
Climate researchers also have access to temperature data sets derived from satellite measurements that essentially measure temperature trends in the whole atmosphere (troposphere) beginning in 1978. The first satellite data set was devised by University of Alabama-Huntsville (UAH) climate researchers John Christy and Roy Spencer. According to UAH measurements, the rate of global average temperature increase is running at 0.13 degrees Celsius per decade.
Researchers don’t just read numbers off satellite feeds to discover temperature trends. They must take into account the orbital decay of satellites, the deterioration of instruments, and changes related to replacing satellites over time. Another team of researchers at Remote Sensing Systems has parsed the satellite data and derived a tropospheric temperature trend of 0.18 degrees Celsius per decade. Clearly, this more closely matches the surface thermometer trends.
In March, another team associated with NOAA’s Center for Satellite Applications and Research (STAR) reported in the Journal of Geophysical Research: Atmospheres its analysis of the satellite temperature data. Earlier, the STAR researchers had calculated that the temperature trend for the total troposphere (TTT) was about 0.16 degrees Celsius per decade. After making further adjustments, the STAR team in March lowered the trend to a bit over 0.14 degrees Celsius per decade.
“The total TTT trend found in this study was only one-half of the climate model simulations,” the STAR researchers note. “Possible reasons for the observation-model differences in trends may include climate model biases in responding to external forcings, deficiencies in the post-millennium external forcings used in model simulations, phase mismatch in natural internal climate variability, and possible residual errors in satellite data sets.” Translation: The models simply run too hot, the historical inputs like volcanic aerosols and ozone to the models may be wrong, a temporary natural cooling trend could be masking warming, and adjustments to the satellite data may be wrong.
The STAR researchers tellingly add that their findings are “consistent with conclusions in McKitrick and Christy (2020) for a slightly shorter period (1979–2014).” In that 2020 study, environmental economist Ross McKitrick and Christy compared the outputs of the latest suite of climate models to satellite, weather balloon, and reanalysis products. They found that every one of the 38 new generation “climate models exhibits an upward bias in the entire global troposphere as well as in the tropics.” The models are predicting much more warming than appears to be occurring. Again, they are running too hot.Time series of model and observation temperature anomalies, global lower troposphere. Individual model runs (gray lines), model mean (black line), and observational mean (blue line). All series shifted to begin at 0 in 1979.
The new STAR study researchers do additionally observe, “A striking feature is that trends during the latest half period (around 0.21–0.22 K/decade) nearly doubled the trends during the first half period (around 0.10–0.12 K/decade) for the global and global ocean means. These large differences in TTT trends between the first and second half periods suggest that the tropospheric warming is accelerating.” It is worth noting that this accelerated trend is still about a third lower than the average of the model projections.
However, McKitrick in a preliminary analysis over at Climate Etc. finds, “the new NOAA data do not support a claim that warming in the troposphere has undergone a statistically-significant change in trend.”
Given that climate science is continually evolving, it’s a good idea to heed University of Colorado climate policy researcher Roger Pielke Jr.’s admonition to “be careful celebrating the results of any one study too much, because science moves ahead and there is no guarantee that any single paper stands the test of time.”
See also: UAH Global Temperature Update for April 2023
Roy Spencer, 2 May 2023
The Version 6 global average lower tropospheric temperature (LT) anomaly for April 2023 was +0.18 deg. C departure from the 1991-2020 mean. This is down slightly from the March 2023 anomaly of +0.20 deg. C.
The linear warming trend since January, 1979 remains at +0.13 C/decade (+0.11 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).
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Hot, Hot, Hot
Issues & insights, 1 May 2023
The sky warriors hold the climate models that have been predicting global doom to be sacrosanct. But as we have reported many times in the past, they’re flawed. A new research paper confirms our warnings. It would be helpful if the brand name media would make note of it. We won’t be holding our own hot air, though.
A January report from Berkeley Earth – self-described as a “non-profit research organization” that “has been preparing independent analyses of global mean temperature changes since 2013″ – starts out as anyone would expect: with a frightful declaration “that 2022 was nominally the fifth warmest year on Earth since 1850.” Which of course means nothing.
It goes on to say “the last eight years have included all eight of the warmest years observed in the instrumental record,” another string of words that sound ominous but aren’t.
What is important, however, is buried near the bottom of the report.
Since 1980, Earth’s temperature trend “has changed little.” The researchers reckon that global temperatures have increased 0.19 degrees Celsius per decade over that period. The data was pulled from 50,498 weather stations combined with sea-surface temperature data.
With this in mind, let’s take a look at the predictions that have been made by the climate models. Their forecasts indicate that temperatures should be increasing at the rate of about 0.28–0.29 degrees Celsius per decade. That’s about 50% higher than the increases Berkeley Earth found.
Other measurements have produced similar results, says Reason science correspondent Ronald Bailey.
“The National Oceanic and Atmospheric Administration (NOAA) finds that the global average temperature has been increasing at the rate of 0.18 degrees Celsius per decade since 1981. NASA’s GISTEMP data set reports an increase of 0.19 degrees Celsius per decade. The U.K.’s Hadley Centre finds the increase is about 0.20 degrees Celsius per decade.
The European Centre for Medium-Range Weather Forecasts reports the global average temperature trend generated by its fifth-generation atmospheric reanalysis (ERA5). Reanalysis is a blend of observations with past short-range weather forecasts rerun with modern weather forecasting models. From 1979 on, the ERA5 calculates that the global average temperature has been increasing at a rate of 0.19 degrees Celsius per decade. The Japan Meteorological Agency’s JRA-55 reanalysis finds the per-decade rate of increase is 0.18 degrees Celsius.”
Meanwhile satellite measurements, which we’ve argued are the standard and the only gauges that can be trusted, tell us global temperatures have averaged an increase of only 0.13 degrees Celsius per decade since Dec. 1, 1978. Taking variables such as “the orbital decay of satellites, the deterioration of instruments, and changes related to replacing satellites over time” into account, Bailey says, produces a rise of 0.18 degrees per decade.
So we have further confirmation that the climate models are running hot.
