I am an admirer of Richard Lindzen, an American physicist whose field is the dynamics of the atmosphere-ocean circulation. In this area he is probably without peer, and it gives him a strong position from which to talk about climate change. He is the most prominent critic of the orthodox, IPCCC view of global warming. He recently gave a speech in London for the Global Warming Policy Foundation. It is too long to simply republish here, but what I have done is to edit it down by about two thirds.
He started his lecture with a quote from a famous essay of 1960 by C. P. Snow, 'The Two Cultures', in which Snow lamented the incapacity of politicians who had no scientific understanding to grapple sensibly with issues that were heavily related to science of one kind or another. Nothing had changed, in nearly seventy years, Lindzen remarked, and that theme echoes through his lecture.
He then set out a simple and understandable account of the climate system, which he sees as the outcome of turbulence between two immensely powerful subordinate systems, that of the oceans and of the atmosphere, which are unevenly heated by the sun, and much affected by land topography. These turbulent interactions have several timescales, ranging from seconds to millennia. There is a greenhouse effect, and its mighty engines are water vapour and clouds. For those who would like a refresher in this area, that section is a must-read. But it requires concentration and persistence.
What follows are his words, after my editing.
'Much of the popular literature (on both sides of the climate debate) assumes that all changes must be driven by some external factor. Of course, the climate system is driven by the sun, but even if the solar forcing were constant, the climate would still vary. This is actually something that all of you have long known – even if you don't realize it. After all, you have no difficulty recognizing that the steady stroking of a violin string by a bow causes the string to vibrate and generate sound waves. In a similar way, the atmosphere–ocean system responds to steady forcing with its own modes of variation (which, admittedly, are often more complex than the modes of a violin string). Moreover, given the massive nature of the oceans, such variations can involve timescales of millennia rather than milliseconds. El Niño is a relatively short example, involving years, but most of these internal time variations are too long to even be identified in our relatively short instrumental record. Nature has numerous examples of autonomous variability, including the approximately 11-year sunspot cycle and the reversals of the Earth's magnetic field every couple of hundred thousand years or so. In this respect, the climate system is no different from other natural systems.
Of course, such systems also do respond to external forcing, but such forcing is not needed for them to exhibit variability… Consider the massive heterogeneity and complexity of the system, and the variety of mechanisms of variability as we consider the current narrative that is commonly presented as 'settled science.'
The popular narrative and its political origins
Now here is the currently popular narrative concerning this system. The climate, a complex multifactor system, can be summarized in just one variable, the globally averaged temperature change, and is primarily controlled by the 1-2% perturbation in the energy budget due to a single variable – carbon dioxide – among many variables of comparable importance.
This is an extraordinary pair of claims based on reasoning that borders on magical thinking. It is, however, the narrative that has been widely accepted, even among many sceptics. This acceptance is a strong indicator of the problem Snow identified.
Many politicians and learned societies go even further: They endorse carbon dioxide as the controlling variable, and although mankind's CO2 contributions are small compared to the much larger but uncertain natural exchanges with both the oceans and the biosphere, they are confident that they know precisely what policies to implement in order to control carbon dioxide levels.'
[At this point Lindzen gives his account of what he thinks the history of the move to decarbonize the world has been. It is widely reported this way, and while I have no quibbles with it, there seems no great reason to repeat it here.]
'This past August, a paper appeared in the Proceedings of the National Academy of Sciences. Littered with 'could be's' and 'might be's', it conclude that 'Collective human action' is required to 'steer the Earth System away from a potential threshold' and keep it habitable. The authors said that this would involve 'stewardship of the entire Earth System – biosphere, climate, and societies', and that it might involve 'decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values…