Climate Scientists Misapplied Basic Physics

A mistake in climate model architecture changes everything. Heat trapped by increasing carbon dioxide just reroutes to space from water vapor instead.

The scare over carbon dioxide was just due to a simple modelling error. A whole category of feedbacks was omitted, which greatly exaggerated the calculated sensitivity to carbon dioxide.

Main Messages

The scientists who believe in the carbon dioxide theory of global warming do so essentially because of the application of “basic physics” to climate, by a model that is ubiquitous and traditional in climate science. This model is rarely named, but is sometimes referred to as the “forcing-feedback framework/paradigm.” Explicitly called the “forcing-feedback model” (FFM) here, this pen-and-paper model estimates the sensitivity of the global temperature to increasing carbon dioxide.1

The FFM has serious architectural errors.2 It contains crucial features dating back to the very first model in 1896, when the greenhouse effect was not properly understood. Fixing the architecture, while keeping the physics, shows that future warming due to increasing carbon dioxide will be a fifth to a tenth of current official estimates. Less than 20% of the global warming since 1973 was due to increasing carbon dioxide.

The large computerized climate models (GCMs) are indirectly tailored to compute the same sensitivity to carbon dioxide as the FFM. Both explain 20th century warming as driven mostly by increasing carbon dioxide.3

Increasing carbon dioxide traps more heat. But that heat mainly just reroutes to space from water vapor instead. This all happens high in the atmosphere, so it has little effect on the Earth’s surface, where we live. Current climate models omit this rerouting. Rerouting cannot occur in the FFM, due to its architecture—rerouting is in its blindspot.4

The alarm over carbon dioxide can be traced back to an erroneous assumption implicitly made in 1896 and never corrected—that there are no significant feedbacks in response to increasing carbon dioxide rather than to surface warming. The rerouting feedback is such a feedback. The FFM introduced another erroneous assumption—that the heat blocked from leaving to space by increasing carbon dioxide causes the same surface warming as if, instead, absorbed sunlight is increased by the same amount,5 or more generally, surface warming is proportional to the sum of all radiative forcings. These assumptions are built into the architecture of the FFM, and are echoed in the GCMs.

Increasing carbon dioxide causes warming in the upper troposphere, because it blocks some heat from escaping to space from there. In the GCMs that heat travels down to warm the surface, where it is like heat from increased absorbed sunlight — due to water vapor amplification of surface warming, less heat is then radiated to space from water vapor. In reality that heat mainly reroutes, radiating to space from water vapor molecules instead. Crucial observations from the last few decades indicate that the heat radiated to space from water vapor has been increasing slightly, suggesting that the effect of rerouting (which lowers the water vapor emission layer) was outweighed by the effect of water vapor amplification due to the surface warming (which raises it).



Blog Posts

This material was introduced in a series of blog posts on Joanne's blog. Note that the forcing-feedback model (FFM) was called the “conventional basic climate model” in these posts (omitting some words for brevity where context allowed). Those with a climate science background will likely find the posts tagged in red of more interest.

Related blog posts:

1 The physicists got it right; the climate scientists got it wrong. It’s the application to climate that is problematic, not the physics. That application is called the “forcing-feedback model” (FFM) here so that it can be discussed explicitly. The FFM is ubiquitous in climate science, embedded in the conversation. It is the basic expression of the feedback-forcing paradigm or framework, which underlies much of climate science. It’s the basic mental model, so pervasive that one might overlook it because it is everywhere. One can construct the FFM just from what “everyone knows” in climate science. Yet it does not have a formal name, perhaps because it has been omnipresent for decades.

2 The errors presumably went unnoticed because critics focused on the values of the parameter values in the model, such as how much heat is trapped by increasing carbon dioxide, rather than on how the model combines those parameters to estimate future warming. Also, for some of the last century, the model seemed to explain the temperature trend.

3 While the GCMs obviously do not treat extra carbon dioxide and extra absorbed sunlight identically, they treat them essentially the same—the GCMs warm the surface by about the same amount for a given forcing of either, and in both cases the GCMs reduce the heat radiated to space by water vapor (due to “water vapor amplification” of the surface warming).

The GCMs are bottom-up models that try to produce observable macro trends by modelling masses of minor details; many details are not known exactly, so some scaling and tweaking is necessary. However the GCMs are effectively tailored to produce the same sensitivity to carbon dioxide as the forcing-feedback model (FFM), in three steps:

  1. The FFM estimates the equilibrium climate sensitivity (ECS) to carbon dioxide as ~2.5 °C.
  2. A sensitivity of ~2.5 °C very roughly accounts for observed warming since 1910. To believers in the FFM, this confirms that increasing carbon dioxide is mostly responsible for 20th century warming.
  3. So GCMs use increasing carbon dioxide as the dominant driver to reproduce 20th century warming. GCMs that do not succeed in this task are not published (see p. 32 here).

But this ECS estimate is too large: fixing the faulty architecture shows it is less than 0.5 °C. So the GCMs omit the main driver(s) of global warming, and are doomed to never be able to explain global warming properly. Notice how they cannot explain global surface temperatures outside the period 1910 to 2000, and how they have not narrowed the ECS estimate by the FFM in the Charney Report of 1979 (namely 1.6 to 4.5 °C)—despite all the effort, computing power, and money spent since 1979, the ECS estimate in AR5 is 1.5 to 4.5 °C.

4 The rerouting feedback may have evaded notice because it cannot exist in the conventional architecture: the conventional basic model only includes feedbacks in response to surface warming. But the rerouting feedback is a response to increased carbon dioxide, which is not a “feedback” as the term is traditionally used in climate science. The Glossary of the IPCC's 5th Assessment Report (2013), while acknowledging the usual meaning of “feedback”, defines a “feedback” more narrowly as a response to surface warming. Some feedbacks that are not in response to surface warming have started appearing in the GCMs, but they are minor.

Including the rerouting feedback in the GCMs would greatly lower their estimate of sensitivity of surface temperature to increasing carbon dioxide—presumably to less than 20% of current estimates, as per the alternative basic model here. This would mean the GCMs could not account for recent warming (either from 1910 or from 1970) with increased carbon dioxide. This is politically difficult, perhaps unthinkable.

5 This assumption is obviously wrong. Extra absorbed sunlight changes the total heat radiated by the Earth, but extra carbon dioxide does not (ignoring the minor surface albedo changes due to surface warming)—because total outflow is just equal to the inflow (once steady state resumes). Increasing carbon dioxide merely redistributes the emissions between the various emitters to space: water vapor, carbon dioxide, the surface, cloud tops, etc. Ever since 1896, climate scientists have been convincing themselves that a decrease in heat outflow is equivalent to a matching increase in heat inflow, as assumed in the FFM. While it is equivalent with respect to the amount of heat on Earth, it is not equivalent in terms of how the outgoing heat is distributed between the various emitters—which is what matters, because surface warming is determined only by the change in emissions from the surface (a warmer surface emits more to space).

Externally-driven albedo involving the Sun is the main cause of warming, but it is omitted from all current climate models.