Science Literature

A previous blog drew attention to negative feedback mechanisms in the Earth's climatic system as a mark (though not a proof) of design. An interesting study by Lindzen and Choi has recently appeared which gives an informative analysis of satellite data spanning 16 years (to 1999). These measurements provide evidence bearing on the Earth's radiation imbalance and climatic feedbacks. From the abstract:

"The observed behavior of radiation fluxes implies negative feedback processes associated with relatively low climate sensitivity. This is the opposite of the behavior of 11 atmospheric models forced by the same SSTs."

Figure 2 from the new paper. "The observed relationship between ocean temperature changes (x-axis) and radiation flux to space (y-axis) is contained in the graph with the red box around it. The other graphs depict the relationship as predicted by 11 different climate models." (Source here)

The data source is the Earth Radiation Budget Experiment (ERBE) which allows measurement of the heat energy emitted by the Earth. Solar energy drives the Earth's climatic system and the incoming radiation is that of a body with a temperature of about 6000 deg K. The Earth absorbs much of this heat energy and emits radiation corresponding to a temperature of about 255 deg K. In a state of equilibrium, the absorbed energy is balanced by the emitted energy.

The equilibrium state is altered by clouds and greenhouse gases (such as water vapour, carbon dioxide and methane). These materials act like an insulating layer, inhibiting energy emission. Equilibrium is restored when the effective temperature of the Earth rises. Carbon dioxide has been the focus of interest over the past two decades, and climate scientists have come to use the term "climate sensitivity" to define the equilibrium response obtained when doubling atmospheric carbon dioxide. The United Nation's Intergovernmental Panel on Climate Change (IPCC) estimates that climate sensitivity is in the range 1.5-5.0 deg C.

The hypothesis made by many climate scientists is that higher carbon dioxide levels increase the global temperature and this allows more water vapour to be held in the atmosphere. This leads to an increasing cloud cover and a greater blanketing effect: a positive feedback mechanism. Thus, the effect of the CO2 increase is amplified and global temperatures rise to restore equilibrium. This is the hypothesis that has been tested by Lindzen and Choi utilising the climate models currently favoured by climate scientists. The observed sea surface temperatures over the 16 year period have been fed into the models to calculate values for the heat energy radiated from the Earth. The results were compared with empirical observations derived from satellites. The findings, plotted in their Figure 2 (above), show that the model predictions are in marked contrast to the ERBE data. The authors point out that the latter reveal negative feedback mechanisms (as yet undetermined) in contrast to all the models which have positive feedback, described by the authors as "spurious positive feedback".

Lindzen and Choi go on to present revised climate sensitivity figures. Whilst the range of variation used in the models is 1.5-5.0 deg C, the authors say that their results "appear to demonstrate a climate sensitivity of about 0.5 deg C". This implies strong negative feedback. Furthermore, if greenhouse gases do warm the planet, their effects would not be distinguishable from natural climatic variations.

Scientists should have liberty to interpret the negative feedback mechanisms as a pointer to our planet's climatic system being designed for life. The Earth's climate is far more stable than the alarmists think. Their views are buttressed by incorporating positive feedback mechanisms into their models to amplify small climatic perturbations and, as Lindzen and Choi have shown, this approach is in tension with the empirical evidence.

It may be of wider interest to discuss a link between this topic and my earlier blog on "Darwin's boulders". The common thread is uniformitarianism adversely affecting the judgment of scientists. Much of climate science is concerned with the present and with short-term forecasting. However, not so many thousand years ago, all are aware of radically different climates during glacial periods. The causes of ice ages have been extensively discussed: some have favoured catastrophism whereas others offer uniformitarian explanations. Recently, the pendulum has swung very strongly towards acceptance of Milankovitch Cycles as the key to understanding glaciations. There are three dominant cycles, affecting the Earth's eccentricity, axial tilt and precession. The variations in solar energy relate to seasonality and geographic location.

Using these cycles, glaciations are said to occur because of predictable causal mechanisms affecting the Earth as it orbits the Sun. The mathematical formulas developed by Milutin Milankovitch are very suitable for incorporating into climate models and simulations, so they have proved to be attractive to climate scientists seeking to explain glaciations. Since the net annual solar radiation falling on the Earth is a constant, the irradiation differences identified by Milankovitch need to be amplified so that they can trigger large scale effects. This necessitates the use of positive feedback in model-building. The root problem is that the science that emerges is built on the assumption of uniformitarianism and model validation using empirical data has been far from rigorous.

This analysis of the way uniformitarianism is a hidden presupposition of much climate science is, of course, a personal view. ID is concerned with design inferences and there is no reason why ID scientists should not take different views on these particular issues. The reason why I am sharing these thoughts is because making design inferences about the Earth's climate system is not a no-go area, and my previous blog explained the basis for a prediction: that negative feedback mechanisms predominate. This is a testable prediction, as the research discussed in this blog has shown. It is just possible that if climate scientists were more alert to design issues, they would have been more critical of their own models (which demanded positive feedback and relative climatic instability). And it can be argued that the presumption of uniformitarianism (Lyell's legacy to the present generation) has not only led to flawed science, it has also cost billions of dollars in a misguided attempt to save the planet.

On the determination of climate feedbacks from ERBE data
Richard S. Lindzen and Yong-Sang Choi
Geophysical Research Letters, 36, L16705,2009 | doi: 10.1029/2009GL039628

Abstract: Climate feedbacks are estimated from fluctuations in the outgoing radiation budget from the latest version of Earth Radiation Budget Experiment (ERBE) nonscanner data. It appears, for the entire tropics, the observed outgoing radiation fluxes increase with the increase in sea surface temperatures (SSTs). The observed behavior of radiation fluxes implies negative feedback processes associated with relatively low climate sensitivity. This is the opposite of the behavior of 11 atmospheric models forced by the same SSTs. Therefore, the models display much higher climate sensitivity than is inferred from ERBE, though it is difficult to pin down such high sensitivities with any precision. Results also show, the feedback in ERBE is mostly from shortwave radiation while the feedback in the models is mostly from longwave radiation. Although such a test does not distinguish the mechanisms, this is important since the inconsistency of climate feedbacks constitutes a very fundamental problem in climate prediction.

See also:

Tyler, D. Was Lyell's "project simply the worldview of naturalism"? ARN Literature Blog, 6 July 2007.