Sunday, December 30, 2012

Effect of Emissions Growth on the Climate

As usual, I'm going to serialize the review I'm writing as I write. Any comments and suggestions are welcome. I've marked in bold the actual papers that will be included in the collection. I'm also thinking to include the Keeling et al. (1976) paper but we have limited space and a long way to go. Another question is whether to include the highly cited paper by Plass in Tellus or the less technical one in American Scientist.

The science of the so-called greenhouse effect has its origins in the 19th century in the work of Joseph Fourier (1827) and John Tyndal (1861) (Held and Soden, 2000). The latter discovered that carbon dioxide and water vapour were the main greenhouse gases. Svante Arrhenius (1896) more fully quantified the greenhouse effect and was the first to raise the issue of the effect of anthropogenic carbon emissions on the global climate. However, Arrhenius thought that the effect of such climate change would be beneficial to society (Kunnas, 2011). Callendar (1938) compared the expected warming effect from accumulated anthropogenic carbon dioxide emissions since the beginning of the century of 0.03°C per decade to the actual warming rate of 0.05C per decade. This was the first analysis of past human-induced warming. However, in predicting future CO2 concentrations he ignored economic growth and so predicted a concentration of 396ppm in 2100, a level that we have already reached and a warming of only 0.5C as he ignored the water vapour feedback that roughly doubles the effects of increased carbon dioxide. Several papers published by Plass in 1956 raised the alarm on climate change in a significant way for the first time. In the most cited of these, Plass (1956a) estimated that carbon dioxide concentrations would rise 30% over the 20th Century and temperatures would increase by 1.1ºC and that warming of the climate would continue for centuries if fossil fuels were extensively exploited. Plass (1956b) presented a less technical account with a clearer warning on future warming. In it he estimated that burning all then known fossil fuel reserves would raise global temperature by 7C once long-run equilibrium of calcium carbonate solution in the oceans was reached. Plass overestimated the direct effect of carbon dioxide, ignored the water vapour feedback and the length of time for the oceans to reach temperature equilibrium, and of course underestimated fossil fuel resources significantly. Still his estimate of the sensitivity of the climate to doubling carbon dioxide was not much higher at 3.8C than today’s consensus estimate of 3ºC (Knutti and Hegerl, 2008).

Regular measurement of atmospheric CO2 concentrations started two years later on Mauna Loa, Hawaii following the International Geophysical Year of 1957 (Keeling, 1960). Within a few years it was obvious that concentrations were rising consistently year by year (Keeling et al. 1976). Attention turned to the first long-run time series reconstruction of anthropogenic CO2 emissions from 1860 to 1969 (Keeling, 1973). Keeling’s results have stood the test of time and are very close to the most recent estimates. Global emissions from fossil fuel use rose from 93 million tonnes of carbon content in 1860 to 3,726 million tonnes of carbon in 1969. Cement production added another 74 million tonnes in 1969.

The articles discussed above show that the anthropogenic climate change problem has been discussed for much longer than may popularly be assumed. William Ruddiman (2003) argued in a controversial paper that anthropogenic climate change itself may be much older than was previously assumed by scientists and in fact anthropogenic emissions of these gases first altered atmospheric concentrations thousands of years ago. He makes three arguments to support his thesis. First, cyclic variations in CO2 and methane driven by Earth-orbital changes during the last 350,000 years predict decreases throughout the last 10,000 years, but the CO2 trend began an anomalous increase 8000 years ago, and the methane trend did so 5000 years ago. Second, published explanations for these gas increases based on natural forcing can be rejected based on paleoclimatic evidence. Third, a wide array of evidence points to anthropogenic changes resulting from early agriculture in Eurasia, including the start of forest clearance by 8000 years ago and of rice irrigation by 5000 years ago. He claims that these emissions were sufficient to prevent a predicted start of reglaciation of northeastern Canada. Anthopogenic climate change was, therefore, beneficial for human society up till the start of the Industrial Revolution but is increasingly less so.

References

Arrhenius, Svante (1896) On the influence of carbonic acid in the air upon the temperature of the ground, Philosophical Magazine Series 5 41(April): 237-276.

Callendar, G. S. (1938) The artificial production of carbon dioxide and its influence on temperature, Quarterly Journal of the Royal Meteorological Society 64: 223-240.

Fourier, J. B. (1827) Memoire sur les temperatures du globe terrestre et des espaces plan- etaires, Mem. Acad. R. Sci. Inst. France 7: 569–604

Held, Isaac M. and Brian J. Soden (2000) Water Vapor Feedback And Global Warming, Annu. Rev. Energy Environ. 25: 441–475.

Keeling, C. D. (1960) The concentration and isotopic abundances of carbon dioxide in the atmosphere, Tellus 12(2): 200-203.

Keeling, C. D. (1973) Industrial production of carbon dioxide from fossil fuels and limestone, Tellus 25: 174-198. Cites = 209

Keeling, Charles D., Robert B. Bacastow, Arnold E. Bainbridge Carl A. Ekdahl, Peter R. Guenther, Lee S. Waterman, and John F. S. Chin (1976) Atmospheric carbon dioxide variations at Mauna Loa observatory, Hawaii, Tellus 28(6): 538-551. Cites = 442

Knutti, Reto & Gabriele C. Hegerl (2008) The equilibrium sensitivity of the Earth's temperature to radiation changes, Nature Geoscience 1: 735 – 743.

Kunnas, J. (2011) How to proceed after Copenhagen, Electronic Green Journal 1(31).

Plass, G. N. (1956a) The carbon dioxide theory of climatic change, Tellus 8(2): 140-154. Cites = 166

Plass, G. N. (1956b). Carbon Dioxide and the Climate, American Scientist (44): 302- 316.

Ruddiman, William F. (2003) The anthropogenic greenhouse era began thousands of years ago, Climatic Change 61(3): 261-293.

Tyndal J. (1861) On the absorption and radiation of heat by gases and vapours, and on the physical connexion of radiation, absorption, and conduction, Philos. Mag. 22: 169–94, 273–85

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