The coal industry and solutions to global warming

Materials World magazine
,
1 Oct 2008

I recently noticed that in Hellemans and Bunch’s outstanding chronology of science and technology, The Timetables of Sciences, there was only one item in the ‘Technology’ column for 1,000AD – ‘China starts to burn coal’. If it was not until the end of the first millennium that mankind began to burn appreciable quantities of coal, when did the combustion of coal, and later oil and gas, begin to release so much carbon dioxide into the atmosphere that it raised the possibility of global warming?

Until about 1850, with a low population, poor standards of living and much burning of wood (an activity which is carbon neutral), all of the carbon dioxide emitted by burning coal could comfortably be sequestered by photosynthesis processes within the Earth’s seas and forests. After this date, burning coal and other fossil fuels progressively increased the amount of this gas in the atmosphere from about 280ppm to the present level of 380ppm.

From our base of 1,000AD, it took a millennium before mankind recognised there was a problem. The first serious attempt to obtain international agreement to curb emissions was the Kyoto Conference of 1997, just three years before the end of the second millennium.

 

Global warming in the media

Moving on to contemporary affairs, it is reassuring that the media is full of articles on global warming. The UK’s Royal Society is to publish an edition of Philosophical Transactions B dedicated to ‘Geo-engineering interventions to combat global warming’, and this in turn has stimulated excellent pieces in the Guardian (Oliver Tickell) and The Economist (unattributed).

Geo-engineering involves making changes to the atmosphere, oceans or forest ecosystems to mitigate global warming. The advocated procedures fall into two categories – to draw down carbon dioxide from the atmosphere or to reflect back sunshine before it reaches Earth. The former usually consists of promoting photosynthesis and other carbon-removing processes by, for example, reducing deforestation and planting trees and, more innovatively, fertilising the oceans with iron to stimulate planktonic algae growth which removes carbon dioxide from the atmosphere.

 

Geo-engineering's solutions to global warming

As far as reflecting sunlight is concerned, the most promising procedure consists of introducing sulphate aerosols into the stratosphere (ie above the weather). Sulphate particles in the atmosphere, or higher, induce cooling. However, James Lovelock calls this a temporary palliative and Doug Parr, Chief Scientist of Greenpeace, decries it as an expression of despair. A more attractive scheme has been proposed by physicist John Latham and colleagues.

Their plan is to raise the reflectivity of marine clouds by a global fleet of unmanned wind-powered yachts afloat on the world’s oceans. These would constantly blow out an ultra-fine mist of salty droplets to act as cloud condensation nuclei.

I started with man’s first use of coal, but I do not end with the coal industry’s demise. A special event occurred on 9 September at Spremberg in Germany when Swedish company Vattenfall officially launched the world’s first pilot unit for a coal-fired power station employing carbon capture and storage. Almost pure oxygen is used to combust the coal and subsequently carbon dioxide is separated from the flue gas and buried permanently in disused oil or gas fields. This will raise the price of electricity appreciably, but widespread adoption would provide a lifeline for the coal industry.

 

Further information

The Timetables of Sciences, by A Hellemans and B Bunch

Philosophical Transactions B, published by the Royal Society

Oliver Tickell, the Guardian

Geo-engineering in The Economist