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).
- Media Release (1 page)
- Essays (all share the same introduction):
- Summary (13 pages, last update 27 Jan 2016).
- Synopsis (26 pages, last update 17 Feb 2016—new pictorial on atmosphere, pages 17 - 21).
- Spreadsheet (Excel, 250 KB). Contains the alternative model to the FFM, with the same physics but the fixed architecture, applied using the data from recent decades. Also contains the OLR (outgoing longwave radiation) model, and a computation of the Planck sensitivity/feedback.
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.
- New Science 1: Introduction to the Series. The conventional basic model (now forcing-feedback model, FFM) of climate is the application of “basic physics” to climate. The idea that “it’s the physics” makes the CO2 theory impregnable in the minds of the establishment. Despite the numerous mismatches between theory and climate observations to date, many climate scientists remain firm in their belief in the danger of carbon dioxide essentially because of the conventional basic model, rather than because of huge opaque computer models. The basic model ignited concern about carbon dioxide; without it we probably wouldn’t be too worried.
- New Science 2: The Conventional Basic Climate Model — Simple. Presenting the conventional basic climate model, in its simplest configuration—the only input is the change in carbon dioxide level, and there are no feedbacks. Computes the no-feedbacks equilibrium climate sensitivity as 1.2 °C.
- New Science 3: The Conventional Basic Climate Model — In Full. Presenting the conventional basic model (FFM) of climate, in full—multiple inputs, and feedbacks. Computes the equilibrium climate sensitivity (ECS) as 2.5 °C.
- New Science 4: Error 1: Partial Derivatives. The conventional basic model relies heavily on partial derivatives. A partial derivative is the ratio of the changes in two variables, when everything apart from those two variables is held constant. But in climate everything depends on everything, so it is not possible to hold everything constant except for only two variables, as required for a partial derivative to exist. The partial derivatives are not empirically verifiable, so employing them in a climate model incurs unknown approximations.
- New Science 5: Error 2: Omitting Feedbacks that are not Temperature-Dependent. In the conventional basic model every “feedback” (something that affects what caused it) is in response to surface warming—directly dependent on the surface temperature, but not on the climate drivers or on other feedbacks. Feedbacks rule the climate. Due to its architecture, if there feedbacks to climate drivers exist (such as the rerouting feedback in post 7 below) the model omits them.
- New Science 6: How the Greenhouse Effect Works. Heat radiated to space (outgoing longwave radiation, or OLR) is mostly emitted by four disparate emissions layers: the water vapor emissions layer, the CO2 emissions layer, cloud tops, and the surface. The hotter a layer, the more it emits. The so-called greenhouse effect exists because OLR is emitted from an emission layer high in the atmosphere, where it is cold, rather than from the surface, where it is warm. The total emissions must equal the heat absorbed from the Sun and has to be emitted somehow, so the surface is much warmer than it would be if most of the OLR wasn’t emitted from high in the cold atmosphere.
- New Science 7: The Rerouting Feedback. We propose the “rerouting feedback”, in which OLR blocked by an increasing CO2 concentration is mostly just rerouted to space via emission from water vapor and clouds tops instead. Occurring high in the atmosphere, this feedback to increasing CO2 is omitted from the conventional basic climate model, which can only contain feedbacks in response to surface warming. Increasing CO2 warms the upper troposphere, because less OLR is emitted from there by CO2 molecules. This heats neighboring molecules, including water vapor molecules in the water vapor emissions layer (WVEL), so more OLR is emitted by water vapor molecules. Because the WVEL emits more it must be at a higher average temperature. The average height of the WVEL declines, becauses the upper troposphere is more stable and convection is less vigorous. Humidity builds up and clouds condense at lower levels, suggesting the average height of the cloud top emission layer would also decline, and more OLR is emitted from cloud tops.
- New Science 8: Applying the Stefan-Boltzmann Law to Earth.The Stefan-Boltzmann equation only applies to a solid isothermal surface, so it cannot be literally applied to Earth. However it can effectively be applied to the Earth as seen from space if the Earth's temperature is considered to be its “radiating temperature”, defined simply as the temperature that satisfies the Stefan-Boltzmann equation with the OLR and emissivity (~0.995) of the Earth.
- New Science 9: Error 3: All Radiation Imbalances Treated the Same. The response of any climate model to increased absorbed solar radiation (ASR) is its “solar response”. Due to its architecture, the conventional basic model applies its solar response to the radiation imbalance caused by any influence on climate, even a radiation imbalance due to increased CO2—one size fits all. However increased ASR causes increased OLR, whereas increased CO2 does not change the total OLR (when steady state resumes, ignoring minor surface albedo feedbacks). Also, increased ASR mainly adds energy to the surface, but increased CO2 blocks energy leaving Earth from the upper atmosphere. So it is physically unrealistic to apply the solar response to the influence of extra CO2.
- New Science 10: Externally-Driven Albedo (EDA). Albedo is the fraction of incoming radiation reflected back out to space without heating the Earth, about 30%. Externally-driven albedo (EDA) is the albedo other than that due to feedback in response to surface warming—presumably it is caused by external influences. Here we show that EDA has at least twice as much influence on surface warming, and maybe much more than that, as the direct effect of variations in the total solar irradiance (TSI).
- New Science 11: An Alternative Modeling Strategy. The road-map for building an alternative model without the problems of the conventional basic model. A paradigm shift from summing forcings to summing warmings is proposed. Each climate influence has its own response (sensitivity and feedbacks), instead of all using the solar response as in the conventional basic model. Radiation must still balance, so this constraint is applied to the sum-of-warmings model. An OLR model based on physical parameters of emission layers estimates the change in OLR, leaving only the CO2 response parameter as an unknown when the sum-of-warmings model is joined to the OLR model to form the alternative model. Observations over a period allow the CO2 response parameter to be estimated, and thus the sensitivity to CO2.
- New Science 12: Modeling the Thermal Inertia of the Earth. The relationship between absorbed solar radiation (ASR) and the radiating temperature is a low pass filter. This is at the heart of the solar response in the sum-of-warmings model within the alternative model.
- New Science 13: The Sum-of-Warmings Model. The sum-of-warmings model independently calculates the surface warming due to each climate driver (such as increasing absorbed solar radiation, or increasing carbon dioxide), then adds them. This allows each climate driver to have its own specific response, including feedbacks.
- New Science 14: Emission Layer Parameters. Basic information about the layers that emit OLR—such as how much OLR comes from each emission layer, and the heights of the emissions layers.
- New Science 15: The OLR Model. The OLR model estimates how much the outgoing longwave radiation (OLR) to space changes with changes to the heights of the emission layers, the lapse rate, the surface temperature, the cloud fraction, and the CO2 concentration.
- New Science 16: The Alternative Basic Climate Model. The sum-of-warmings model (post 13) and the OLR model (post 15) are joined together to form the alternative basic model.
- New Science 17: Solving the Mystery of the Missing “Hotspot”. In the conventional models (including the GCMs), surface warming for any reason causes the water vapor emissions layer (WVEL) to ascend, creating “the hotspot”. In the alternative model, surface warming and the solar response both cause the WVEL to ascend, while the CO2 response (how the planet reacts to increased CO2) causes the WVEL to descend—which is consistent with the rerouting feedback. The last few decades saw surface warming, increased ASR, and increased CO2, while the empirical data from the radiosondes and the better satellite analysis showed that the WVEL did not ascend and may have descended. The conventional models (including the GCMs) are wrong—they apply the solar response to both increased ASR and increased CO2, so they say all the forces on the WVEL were causing it to ascend. The alternative model resolves the data—there were opposing forces acting on the WVEL, the hotspot is indeed missing, and the CO2 response was stronger than the solar response over the last few decades.
- New Science 18: Calculating the ECS Using the Alternative Model. Fitting the data to the alternative model, we conclude that the equilibrium climate sensitivity (ECS), the surface warming per doubling of the CO2 concentration, might be almost zero, is likely less than 0.25 °C, and most likely less than 0.5 °C. Most likely, less than 20% of the global warming since 1970 is due to increasing carbon dioxide. The CO2 response is less than a third as strong as the solar response—both measured in degrees of surface warming per unit of radiation imbalance.
- New Science 19: Comments on Conventional versus Alternative. General comments tying together some of the main ideas of the series to date.
- New Science 19b: Synopsis announced. Download the synopsis.
Related blog posts:
- Lucia has a Bad Day with Partial Derivatives. Over at the Blackboard, Lucia thought David had made some errors with partial derivatives in post 3, and was talking about GCMs in post 4. This post is a reply, showing her how to do partial differentiation, and correcting her misconception.
- Lucia has a Bad Week on Partial Derivatives. Over at the Blackboard, Lucia dug a deeper hole, this time focusing on the existence of the partial derivatives in the conventional basic model. This post is a reply, showing that her alternative development was mere notational trickery. Having read carefully through Lucia‘s two posts and their comments, we are still waiting for Lucia to find any mistakes in our posts above or even made any informed criticism of them.
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:
- The FFM estimates the equilibrium climate sensitivity (ECS) to carbon dioxide as ~2.5 °C.
- 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.
- 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.