Who knew what and when?

A recent article in the Guardian, which was also carried through a number of other media outlets, implied some prior knowledge within the oil and gas industry of climate change and the impact of carbon dioxide emissions from fossil fuel use long before others had recognised its impact. The assertion was based on unearthed correspondence within Exxon where carbon dioxide emissions were discussed as early as 1981. The article goes on to say that “Climate change was largely confined to the realm of science until 1988, when the climate scientist James Hansen told Congress that global warming was caused by the buildup of greenhouse gases in the atmosphere, due to the burning of fossil fuels.”

In fact, information about the role of carbon dioxide as a greenhouse gas in the atmosphere has been widely available for over a century and has its foundation as far back as the early 19^th Century, nearly 200 years ago. At that time, physicists were coming to terms with radiation physics and were attempting to understand why the Earth had a stable temperature. Knowing the energy falling on the planet from the Sun and after building an understanding of the radiation outwards from the Earth itself, the expected temperature of the planet could be derived. Unfortunately the calculation resulted in a number of somewhere around -15°C, which was clearly some 30°C lower than the observed temperature (about +15°C). Something else was in play, but at the time this was unclear. By 1862, an understanding of the role of certain gases in the atmosphere had been established, now more widely known as the “greenhouse effect”.

In 1896, Swedish chemist Svante Arrhenius used this information for a paper on the role of carbon dioxide that remains the foundation of 120 years of analysis of the Earth’s temperature and resulting climate (On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground).

In this paper Arrhenius established a methodology for linking the change in surface temperature with the change in the level of carbon dioxide (carbonic acid as he referred to it as) in the atmosphere. Table VII of the paper showed the results of his calculation for different levels of carbon dioxide in the atmosphere ranging from K=0.67 (where K=1 for the level at the time) to K=3.0. For the latitude of the equator he derived the following results;

	Carbonic acid = 0.67	Carbonic acid = 1.5	Carbonic acid = 2.0	Carbonic acid = 2.5	Carbonic acid = 3.0
Temperature change at Latitude 0°	-3.02°C	3.15°C	4.95°C	6.42°C	7.3°C

The Arrhenius paper discusses the work of a Professor Högblom, another Swedish scientist of the day, who had even calculated how much the burning of coal at that time (500 million tonnes per annum) might change the surface temperature of the planet. The number was very small, but today annual fossil carbon extraction is some twenty to thirty times greater than this and more importantly the cumulative extraction (which we now know is what actually matters) since the late 19^th century is hundreds of time this level.

By the late 1950s, thanks to the work of Charles Keeling of Scipps Institution of Oceanography in California, accurate measurements of atmospheric carbon dioxide were being made. In 1961, Keeling produced data showing that carbon dioxide levels were rising steadily in what became known as the “Keeling Curve”. In 1965, the first truly public warning as to the impact of rising levels of carbon dioxide in the atmosphere came from the President’s Science Advisory Committee (President Lyndon B. Johnson), with the words “Through his worldwide industrial civilization, Man is unwittingly conducting a vast geophysical experiment. . . . . 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.”

There have been many other such references and warnings, ranging from the 1988 testimony to Congress by NASA scientist James Hansen to Al Gore’s film Inconvenient Truth in 2006. Through all of these the story hasn’t really changed from the original calculations of Arrhenius in 1894, rather the understanding and methodology has been increasingly refined and improved.

The above timeline isn’t new and can be found in much more detail in many books, blogs and periodicals. Nor is it even close to comprehensive, with dozens of other scientists and institutions making important contributions to the early analysis, particularly in the 1950s. Nevertheless, it seems to need repeating. Although atmospheric warming may not have been a dinner table conversation in the 1980s, it wasn’t a secret either. A look at the use of the phrases “greenhouse effect”, “global warming” and “climate change” shows that they appeared in books in the 1970s.

Nor was it largely confined to the realm of science. Hollywood had even picked up on the issue in the 1973 film Soylent Green, where the greenhouse effect is specifically mentioned and is to some extent a core issue in the dystopian future that is postulated.

Rather, what is unusual about the climate issue is the present day questioning of the background science that has come some 100-200 years after the scientific basis was first formulated and largely established, rather than at the time. In my forthcoming book, “Carbon Pricing Matters”, I touch on this issue as follows;

The need to manage global emissions and put a halt to the relentless build-up of carbon dioxide in the atmosphere requires the intervention of governments and cooperation between them to ensure their success; particularly when implemented through a cost on carbon dioxide emissions. There is an ongoing debate around the role of government and the degree to which it should be allowed to address the issue of global warming. There are many who believe that government should have only a modest role in society; others accept a much wider role, including one to solve broad-based issues that affect society at large, for example, the build-up of carbon dioxide in the atmosphere. For the latter group, a carbon price may not go far enough; it is a tool designed to tease out the solution over a generation or more. In the case of those who seek to limit the role of government, the imposition of a pricing mechanism across the entire economy can be seen as a step too far and may even raise questions about the foundation upon which the mechanism is based; the science of climate change.