January 27, 2013
by J. Barkley Rosser, Jr.
1. In 1971 scientific opinion was evenly split between whether the world would cool due to rising particulate and sulfate emissions from burning coal or warm due to carbon dioxide emissions from burning fossil fuels. World temperatures had been gradually declining since around 1940 and would only turn around to rise in an approximately straight line in the mid-1970s. By 1975 it had come to be realized by most scientists that indeed the heating effect of carbon dioxide would dominate the cooling effect from particulate aerosols and sulfates. The main reason for this is that carbon dioxide is slow to leave the atmosphere, whereas particulates and sulfates tend to leave with the rain. By 1978, there were no more articles in leading scientific journals arguing for global cooling. Symbolic of the shift between 1971 and 1975 are two papers by the late Stephen Schneider, one of the world’s leading climatologists, with the one in 1971 suggesting global temperature could go either up or down and the one in 1975 saying it was going to go up, which was an accurate but courageous forecast given that up until then global temperature had been going down for over 30 years.
Stephen H. Schneider and S. Rasool, 1971, “Atmospheric Carbon Dioxide and Aerosols: Effect of Large Increases on Global Climate,†Science, vol. 173, pp. 138-141.
Stephen H. Schneider, 1975, “On the Carbon Dioxide Confusion,†Journal of Atmospheric Science, vol. 32, pp. 2060-2066.
2. While the most straightforward way to reduce carbon dioxide emissions is to drive less and use less electricity, in short, conservation, and much can be done by many on these fronts, for most of us there are limits in our current society to how much we can do. This moves us to seek alternatives to burning fossil fuels: coal, oil, and natural gas, to allowing us to drive and use electricity. For automobiles, hybrid or electric engines are probably the most immediately available technologies, although others may be available in the future. While we are probably going to expand the use of natural gas in the near future for electricity production, which is cleaner than coal, other alternatives being used are wind and solar. Wind turbines have the problem of attracting endangered bats. However, the batteries in hybrid and electric cars, the magnets in wind turbines, and photovoltaic cells for solar power all share a problem: they all rely on the use of rare earth elements. The mining of these elements is highly polluting and most of them are located in China, which involves possible diplomatic and economic issues. We face serious choices if we wish to seriously expand the use of these technologies, although there is some hope that we may be able to develop photovoltaic cells that do not rely on the use of these elements. [Read more…]