Current CO2 concentration in the atmosphere

LBJ knew

LBJ being, of course, US President Lyndon Baines Johnson. And what he knew was that even in 1965 it was clear that we were on a path headed toward some serious climate change troubles. In November of that year he received a report form the Environmental Pollution Panel, President’s Science Advisory Committee, entitled “Restoring the Quality of Our Environment”. Appendix Y4, Section I of that document, “Carbon Dioxide from Fossil Fuels — the Invisible Pollutant” includes this text in its conclusion:

Through his worldwide civilization, Man is unwittingly conducting a vast geophysical experiment. Within a few generations he is burning the fossil fuels that slowly accumulated in the earth over the past 500 million years. The CO2 produced by this combustion is being injected into the atmosphere; about half of it remains there. The estimated recoverable reserves of fossil fuels are sufficient to produce nearly a 200% increase in the carbon dioxide content of the atmosphere.

By the year 2000 the increase in atmospheric CO2 will be close to 25%. This may be sufficient to produce measurable and perhaps marked changes in climate, and will almost certainly cause significant changes in the temperature and other properties of the stratosphere. At present it is impossible to predict these effects quantitatively, but recent advances in mathematical modelling of the atmosphere, using large computers, may allow useful predictions with the next 2 or 3 years.

The climatic changes that may be produced by the increased CO2 content could be deleterious from the point of view of human beings. The possibilities of deliberately bringing about countervailing climatic changes therefore need to be explored. A change in the radiation balance in the opposite direction to that which might result from the increase of atmospheric CO2 could be produced by raising the albedo, or reflectivity, of the earth. Such a change in albedo could be brought about, for example by spreading very small reflecting particles over large oceanic areas. The particles should be sufficiently buoyant so that they will remain close to the sea surface and they should have a high reflectivity, so that even a partial covering of the surface would be adequate to produce a marked change in the amount of reflected sunlight. Rough estimates indicate that enough particles partially to cover a square mile could be produced for perhaps one hundred dollars. Thus a 1% change in reflectivity might be brought about for 500 million dollars a year, particularly if the reflecting particles were spread in low latitudes, where the incoming radiation is concentrated. Considering the extraordinary economic and human importance of climate, costs of this magnitude do not seem excessive. An early development of the needed technology might have other uses, for example in inhibiting the formation of hurricanes in tropical oceanic areas.

Note that even then, almost 48 years ago, we were already talking about geohacking, in this case via what’s today commonly called SRM (solar radiation management).

I am also struck by the prediction that by the year 2000, which surely sounded like a science fictional, far-off future to people in 1965[1], we would have increased the natural level of atmospheric CO2 by 25% and possibly caused Very Bad Things to happen. Pre-industrial CO2 plus 25% would bring us to almost exactly 350ppm, a number we’re all more than familiar with for its scientific and activist implications. That prediction was too optimistic, however, as we hit that level in the late 1980′s; perhaps they didn’t foresee just how passionate our embrace of fossil fuels would grow over the intervening years.

I bring all this up for more than mere historical interest, which should be reason enough; I think it’s vital to have vivid reminders that even nearly half a century ago not only did scientists know we were playing with hell and high water, but the US Federal Government did, as well.

A document with the front matter and appendix Y4 is here.

[1] It certainly sounded that way to me back then, but I was a kid, and everything more than a couple of years in the future sounded science fictional.

1 comment to LBJ knew

  • From eyeballing the Keeling curve 350 ppm in 2000 looks about right as a linear extrapolation of the rate of increase over the 1960s. I guess they couldn’t bring themselves to believe in an exponential increase.