Soil Moisture Illustrates Why IPCC Computer Models Fail

Written by Dr. Tim Ball

Claims of human produced CO2 causing climate change are based on output of computer models of the Intergovernmental Panel on Climate Change (IPCC). Programmed to produce predetermined results their output is used for global and national policies on energy even though projections have been consistently wrong. Failures caused a switch from predictions to scenarios, but it didn’t help. Most recent scenarios projected increases between 1.3 and 2.8°C, but temperatures declined as CO2 increased. Since 2000 the trend is wrong and for the last five years is below the lowest IPCC projection.


A CO2 trend overlay suggests it’s the main variable driving projections, but it’s not the only variable that invalidate the models as the IPCC themselves identify. The difference between what they acknowledge is missing or inadequate and the certainty of their conclusions is so stark it suggests it’s premeditated.

There are major limitations of data, like temperature as Watts and D’Aleo explain, and very limited understanding of mechanisms. However, there are many lesser variables critical to understanding what creates and determines the weather. Analogies are useful, but dangerous: witness the analogy of the atmosphere to a greenhouse. One limitation is the role of moisture in transferring heat and energy not considered in the greenhouse yet critical in the atmosphere.

Consider the role of moisture in controlling human body temperature. Few people know the skin is the largest organ of the body performing an important function as the interface between the inner body and the atmosphere and controlling body temperature.  The amount of moisture used in sweating is a fraction of the total amount in the body, but critical to controlling temperature.

The land and water surface of the Earth are the interface or skin between the subsurface and the atmosphere. The Earth is heated by shortwave energy from the  sun that is stored in the surface. Energy for sweating is taken from the body, which cools the body. Evaporation of water from the surface takes heat stored in the earth or water and transfers it to the atmosphere. The amount of soil moisture is estimated as “0.001% of the total water found on Earth,” but like the sweat it is critical to controlling temperature.

A severe credibility problem for proponents of anthropogenic global warming is the challenge that models can’t forecast beyond 72 hours, but they’re certain about much longer forecasts. They said there’s a difference between weather and climate predictions, but climate is an average of the weather and therefore only as valid as it. The argument is belied by comments about missing variables such as this one from NASA that confirms the importance of soil moisture:

Soil moisture is a key variable in controlling the exchange of water and heat energy between the land surface and the atmosphere through evaporation and plant transpiration. As a result, soil moisture plays an important role in the development of weather patterns and the production of precipitation.

The National Research Council suggested why weather forecast models don’t work in 1992.

Despite the importance of soil moisture information, widespread and/or continuous measurement of soil moisture is all but nonexistent. “The lack of a convincing approach of global measurement of soil moisture is a serious problem” .

This was in 1992 but little had changed when Chapter 8 of the 2007 IPCC Report appeared.

Since the TAR, there have been few assessments of the capacity of climate models to simulate observed soil moisture. Despite the tremendous effort to collect and homogenize soil moisture measurements at global scales (Robock et al., 2000), discrepancies between large-scale estimates of observed soil moisture remain.

Global climate models are composites of individual models for each component of the atmosphere. They assume the smaller model output is real data and they know how it interacts with all other model inputs. Even that is a problem as Koster et al., explain.

The soil moisture state simulated by a land surface model is a highly model-dependent quantity, meaning that the direct transfer of one model’s soil moisture into another can lead to a fundamental, and potentially detrimental, inconsistency.


The NASA statement identifies another limitation of the IPCC model when they refer to “the exchange of water and heat energy between the land surface and the atmosphere.”

Again the IPCC model fails as Chapter 8 notes;

Unfortunately, the total surface heat and water fluxes (see Supplementary Material, Figure S8.14) are not well observed.

This means they don’t have the data, but they also admit they cannot simulate the mechanisms involved.

For models to simulate accurately the seasonally varying pattern of precipitation, they must correctly simulate a number of processes (e.g., evapotranspiration, condensation, transport) that are difficult to evaluate at a global scale.

Limitations of soil moisture data and mechanisms in the computer models invalidate any output they produce, but it’s only one of many. What is outrageous is these gross inadequacies do not stop them claiming that

Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.


Most” and “very likely” are greater than 90 percent by their definition. These are high levels of certainty even in research based on solid data with reasonable understanding of the mechanisms. They’re totally unjustified from the computer model inputs and outputs and the failure of every single prediction or scenario. Magnitude of the disparity suggests those who produce it are either scientifically incompetent or have created the result. Premeditation of a predetermined result has no place in science.



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