In recent years interest in geoengineering has centered on the possibility of substituting it for reductions in greenhouse gas (GHG) emissions widely promoted as a solution to hypothesized global warming/climate change. Although it could be both more effective and cost-effective than GHG emission reductions for this purpose, a more fundamental question needs to be answered before geoengineering is seriously considered: Is it likely to be needed and under what circumstances?
I presented a paper at a conference in Moscow in 2011 on this topic. I explored the likely causes, primarily astronomical in nature, of climate change, summarized new observationally-based forecasts of future global temperatures based on recently proposed solar cycles which provide amazingly accurate hindcasts over the last 10,000 years, and then used these forecasts, as well as previous knowledge of ice age cycles, to suggest when geoengineering might be useful in avoiding climate destabilization. I argued that a new Ice Age is inevitable over the next few millennia unless humans undertake counter measures using geoengineering given the minor effects of changes in CO2 levels. A new ice age would be catastrophic both environmentally and for human welfare, particularly for countries in the northern latitudes such as Canada, Russia, and the US.
Although the causes and timing of ice ages need to be still better understood, Greenland ice cores indicate that Earth’s temperatures have been dropping for over 3,000 years, as in previous interglacial periods. I proposed that the next ice age is most likely to start when the cyclical temperatures are likely to be lowest–near the middle of each millenial solar cycle. It is therefore vital that we better understand these cycles and formulate plans to reduce the chances of a new Ice Age onset before this catastrophe happens. Together with an analysis of temperatures during previous interglacial periods, this suggests that the next ice age may start between about 500 and 2,500 years from now.
My presentation can be found on pages 24-34 of a section of the conference proceedings, which became available last week. The 2011 Moscow Conference was on Problems of Adaptation to Climate Change and sponsored by the Russian Fedeation Government. The reference for the section proceedings is Yu. A. Izrael, A. G. Ryaboshapko, and S. A. Gromov, editors, Investigation of Possibilities of Climate Stabilization Using New Technologies, Proceedings of International Scientific Conference, “Problems of Adaptation to Climate Change” (Moscow, 7–9 November 2011), Russian Academy of Sciences, Moscow, 2012.
If you believe that planetary surface temperatures are all to do with radiative forcing rather than non-radiative heat transfers, then you are implicitly agreeing with IPCC authors (and Dr Roy Spencer) that a column of air in the troposphere would have been isothermal but for the assumed greenhouse effect. You are believing this because you are believing the 19th century simplification of the Second Law of Thermodynamics which said heat only transfers from hot to cold – a “law” which is indeed true for all radiation, but only strictly true in a horizontal plane for non-radiative heat transfer by conduction.
The Second Law of Thermodynamics in its modern form explains a process in which thermodynamic equilibrium “spontaneously evolves” and that thermodynamic equilibrium will be the state of greatest accessible entropy.
Now, thermodynamic equilibrium is not just about temperature, which is determined by the mean kinetic energy of molecules, and nothing else. Pressure, for example, does not control temperature. Thermodynamic equilibrium is a state in which total accessible energy (including potential energy) is homogeneous, because if it were not homogeneous, then work could be done and so entropy could still increase.
When such a state of thermodynamic equilibrium evolves in a vertical plane in any solid, liquid or gas, molecules at the top of a column will have more gravitational potential energy (PE), and so they must have less kinetic energy (KE), and so a lower temperature, than molecules at the bottom of the column. This state evolves spontaneously as molecules interchange PE and KE in free flight between collisions, and then share the adjusted KE during the next collision.
This postulate was put forward by the brilliant physicist Loschmidt in the 19th century, but has been swept under the carpet by those advocating that radiative forcing is necessary to explain the observed surface temperatures. Radiative forcing could never explain the mean temperature of the Venus surface, or that at the base of the troposphere of Uranus – or that at the surface of Earth.
The gravitationally induced temperature gradient in every planetary troposphere is fully sufficient to explain all planetary surface temperatures. All the weak attempts to disprove it, such as a thought experiment with a wire outside a cylinder of gas, are flawed, simply because they neglect the temperature gradient in the wire itself, or other similar oversights.
The gravity effect is a reality and the dispute is not an acceptable disagreement.
The issue is easy to resolve with a straight forward, correct understanding of the implications of the spontaneous process described in statements of the Second Law of Thermodynamics.
Hence radiative forcing is not what causes the warming, and so carbon dioxide has nothing to do with what is just natural climate change.
Given the high and accelerating pace of technological and scientific capacity (notwithstanding the recent contrascientific political CAGW putsch attempt), prescribing actions for humanity 500 to 2500 years in the future is like a babbling infant giving advice on running and adjusting complex machinery. It’s hubristic, foolish, and totally irrelevant.
The only value of such articles as this is to deflect patently counter-productive waste of resources and human effort (economics) chasing self-destructive goals.
If we build a spacegoing civilisation, which we are well capable of doing over the next few decades with little more than current technology, then it will be possible to cheaply put square miles of tinfoil in orbit acting either as sunscreens or mirrors depending on what is required.
This will more than offset any solar changes,negative or positive.
I have been suggesting for several years that, as a precaution, we should be dotting the great white north with coal generation plants designed, not to produce electricity, but to maximize soot production. They could provide local electricity as useful, and burn clean until such time as they might be needed. But if a big lurch in the cold direction comes, we had better have this geo-engineering capacity already in place.
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