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.