From Roy Spencer’s Global Warming Blog
Roy W. Spencer, Ph. D.
See, I told you so.
One of the most fundamental requirements of any physics-based model of climate change is that it must conserve mass and energy. This is partly why I (along with Danny Braswell and John Christy) have been using simple 1-dimensional climate models that have simplified calculations and where conservation is not a problem.
Changes in the global energy budget associated with increasing atmospheric CO2 are small, roughly 1% of the average radiative energy fluxes in and out of the climate system. So, you would think that climate models are sufficiently carefully constructed so that, without any global radiative energy imbalance imposed on them (no “external forcing”), that they would not produce any temperature change.
It turns out, this isn’t true.
Back in 2014 our 1D model paper showed evidence that CMIP3 models don’t conserve energy, as evidenced by the wide range of deep-ocean warming (and even cooling) that occurred in those models despite the imposed positive energy imbalance the models were forced with to mimic the effects of increasing atmospheric CO2.
Now, I just stumbled upon a paper from 2021 (Irving et al., A Mass and Energy Conservation Analysis of Drift in the CMIP6 Ensemble) which describes significant problems in the latest (CMIP5 and CMIP6) models regarding not only energy conservation in the ocean but also at the top-of-atmosphere (TOA, thus affecting global warming rates) and even the water vapor budget of the atmosphere (which represents the largest component of the global greenhouse effect).
These represent potentially serious problems when it comes to our reliance on climate models to guide energy policy. It boggles my mind that conservation of mass and energy were not requirements of all models before their results were released decades ago.
One possible source of problems are the model “numerics”… the mathematical formulas (often “finite-difference” formulas) used to compute changes in all quantities between gridpoints in the horizontal, levels in the vertical, and from one time step to the next. Miniscule errors in these calculations can accumulate over time, especially if physically impossible negative mass values are set to zero, causing “leakage” of mass. We don’t worry about such things in weather forecast models that are run for only days or weeks. But climate models are run for decades or hundreds of years of model time, and tiny errors (if they don’t average out to zero) can accumulate over time.
The 2021 paper describes one of the CMIP6 models where one of the surface energy flux calculations was found to have missing terms (essentially, a programming error). When that was found and corrected, the spurious ocean temperature drift was removed. The authors suggest that, given the number of models (over 30 now) and number of model processes being involved, it would take a huge effort to track down and correct these model deficiencies.
I will close with some quotes from the 2021 J. of Climate paper in question.
“Our analysis suggests that when it comes to globally integrated OHC (ocean heat content), there has been little improvement from CMIP5 to CMIP6 (fewer outliers, but a similar ensemble median magnitude). This indicates that model drift still represents a nonnegligible fraction of historical forced trends in global, depth-integrated quantities…”
“We find that drift in OHC is typically much smaller than in time-integrated netTOA, indicating a leakage of energy in the simulated climate system. Most of this energy leakage occurs somewhere between the TOA and ocean surface and has improved (i.e., it has a reduced ensemble median magnitude) from CMIP5 to CMIP6 due to reduced drift in time-integrated netTOA. To put these drifts and leaks into perspective, the time-integrated netTOA and systemwide energy leakage approaches or exceeds the estimated current planetary imbalance for a number of models.“
“While drift in the global mass of atmospheric water vapor is negligible relative to estimated current trends, the drift in time-integrated moisture flux into the atmosphere (i.e., evaporation minus precipitation) and the consequent nonclosure of the atmospheric moisture budget is relatively large (and worse for CMIP6), approaching/exceeding the magnitude of current trends for many models.”
They don’t even obey gravity or acknowledge that the earth’s atmosphere is an open system that can expand and contract – or acknowledge that gases aren’t hydraulic.
Ignoring specific heat per volume and density changes makes the models invalid at any output.
And effects of specific heat in the atmosphere is well demonstrated by the obvious differences in air temperature behavior in dry desert areas versus humid areas. I suspect the models don’t properly address that for a reason; and not a scientific one.
It’s why averaging Las Vegas temperatures with Miami temperatures with Bismarck, ND is so wrong. T is not a good proxy for heat.
pv = nrT is not part of their religious dogma.
I used to evaluate thermal hydraulic (T/H) computer codes for nuclear reactors for the US Govt. I also used to organize test exercises for the international community of T/H modelers where they the participants were provided with the fundamental information needed to model actual test facilities, some of which were scale models, but some of which were actual operating nuclear reactors and nuclear power plants.
I remember specifically one exercise involving a very simple scenario with a very simple facility that caused the modelers a lot of problems, because it involved the creation of very low temperatures due to gas expansion above a water surface. The codes were not able to model this phenomenon, so the modelers had to be “creative” to get the right answer. The most creative participants were from organizations which had no skin in the game – they worked for academic or governmental organizations and did not have to justify their results to the regulators. One of them used a “negative flow loss coefficient” (very un-physical) to get the answer he wanted.
Another experiment was a one dimensional experiment of fluid and particulate flow in a long tube. The modelers all used the same basic code, but were allowed to “tune it” as they saw fit. The results from about 1 dozen participants varied by about 6 orders of magnitude, with the academic and government participants again showing the most “creative” ways to model the physical system.
I have been a skeptic of the climate models ever since I first heard about them, because of my experience modeling well characterized systems in nuclear plants. It was very hard to model certain scenarios over period of several days inside a closed building or even a well understood reactor, and I could not understand how anyone could think they could really model the weather for an entire planet for decades at a time without lots of creative tuning. Which renders the results immediately suspect.
Failure to achieve a mass and energy balance in a T/H code is a good indication that it is not fit for purpose.
When climate modelers talk about increases of X petajoules of “ocean heat content” over the last 50 years or so, given the vast mass of the oceans, this translates to a temperature variation of a few thousandths (0.001) of a degree C. Can the Argos buoys, which sometimes measure temperatures in the deep ocean, measure temperature to that precision, or are all modeled variations in OHC lost in instrument error, and are therefore undetectable in reality?
The entire mass of the atmosphere over 1 m2 of the earth’s surface is equivalent to a height of about 10,330 meters at sea level pressure (about 1013 mb average). If such a column of air contained 1% water vapor by volume, the mass of water vapor would be about 78.7 kg at 15 C. In reality, the water vapor content at altitude would be much less than 1%, since cold air at altitude cannot hold that much water vapor without precipitation.
The average depth of the oceans is about 3.7 km, meaning that the mass of water in 1 m2 of ocean is about 3700 m * 1000 kg/m3 = 3.7 million kg.
This means that a major change in the mass of water vapor in the atmosphere would not result in much change in the mass of water in the oceans. Doubling the water vapor in the atmosphere would decrease the ocean mass by about 21 ppm in this example. This means that an error in the mass balance of the water in the atmosphere would go unnoticed in the Ocean Heat Content calculation.
But if the water vapor content of the atmosphere (calculated by a model) increases, the additional water has to come from evaporation from a body of water, which requires about 2400 kJ/kg of latent heat (at 15 C). This would have very little effect on the total heat content of the oceans, but a large effect on the atmospheric heat balance.
When the same models are used to predict melting of polar ice caps, the heat of melting ice is about 333 kJ/kg, or about 333 MJ per m3 of water formed. If the column of air over 1 m2 is heated by 1 deg C, the heat required is about 105 MJ. This means that if there was “global warming” of 1 deg C over the poles, it would melt a depth of ice of 105 / 333 = 0.315 m, but only during the seasons when the air temperature is above 0 deg C.
If the ice was melted to a depth of 0.315 m over the entire Antarctic and Greenland ice sheets (15.7 million km2), it would form about 4.95*10^12 m3 (or 4950 gigatonnes) of water added to the oceans. But since the area of the oceans is 361 million km2 = 3.61*10^14 m2, the resulting sea level rise would be (4.95*10^12) / (3.61*10^14) = 0.0137 m, or about 0.54 inch.
So if the entire atmosphere was warmed up by 1 C, it would have enough heat to melt enough ice to raise sea level by 1.37 cm, or 0.54 inch. From the point of view of a simple heat balance over water and ice, this is not much to worry about.
When will these ultra-sophisticated climate modelers learn to do a heat and mass balance, and realize that their “dreaded” warming of 1.5 or 2.0 C is literally an inch in the ocean?
“this translates to a temperature variation of a few thousandths (0.001) of a degree C. Can the Argos buoys, which sometimes measure temperatures in the deep ocean, measure temperature to that precision,”
It’s not a matter of precision, it is a matter of accuracy. The Argo floats have a measurement uncertainty of +/- 0.5C. It doesn’t matter if you can measure down to the thousandths digit if you don’t know if it is accurate or not. .001C +/- 0.5C is meaningless.