Daylight robbery – Greenhouse gases and the depletion of the Earth's resources

Materials World magazine
,
1 Aug 2008

Mentioning Pascal's Wager in a discussion of global warming in my July column has resulted in a flurry of e-mails (as a reminder, Pascal suggested that is was advisable to believe in God and eternal life because if you are wrong it would not matter, but if correct, eternal bliss is yours). One reader pointed out that as there are many Gods how could you be sure to have made the right choice? Another feared that I had joined the three per cent of Fellows of the Royal Society who believe in the supernatural. A third reminded me that one has absolutely no control over what one truly believes and a feigned belief in God is worthless.

By referring to Pascal's Wager I had not intended to enter into a theological debate, but rather to argue that it is preferable to believe in the probability that man-induced global warming will occur rather than to reject it. This remains true even if global warming turns out to be a snare and a delusion. My starting point is to recognise that there are a number of reasons for carefully controlling the concentration of carbon dioxide in the atmosphere. As is well known, gases in the atmosphere with more than two atoms in their molecule, such as carbon dioxide, are transparent to incoming short wave radiation from the sun but absorb the longer wavelength radiation which is re-emitted from the Earth. This leads to global warming – the greenhouse effect.

 

Natural occurrence of greenhouse gases

It is fortunate that greenhouse gases existed naturally in our atmosphere, for had they been absent the Earth's average temperature would not have been a comfortable 14ºC (close to its present level), but -19ºC and the Earth would be a frozen and lifeless planet. In addition to creating the warmth to make life possible, carbon dioxide from the atmosphere was an essential ingredient for plants to produce, by photosynthesis, the carbon-based chemicals which constitute the food and structure of all lifeforms, including our own. Photosynthetic processes also provided virtually all the atmospheric oxygen. We do not know the optimum level of carbon dioxide in the atmosphere to permit these photosynthetic and warming processes to occur, but it is surely prudent to control the concentrations to close to the ‘natural', and hence ‘proven', level.

Chemical analysis of air trapped in polar ice of various ages reveals that, from the end of the last Ice Age to about 1850, the carbon dioxide level was fairly constant and close to 280ppm. Thereafter and to the present day, coincident with industrialisation and burning of fossil fuels, the level has risen inexorably to 385ppm and is expected to increase to at least 560ppm by 2050. To permit a doubling in concentration of such an important component of our atmosphere seems imprudent.

 

Depletion of natural resources

There is another angle to this moral and technological dilemma. By 2050 much of the readily-accessible oil and gas reserves will be exhausted. In the 200 years from 1850 to 2050, the fossil fuels accumulated in the Earth's crust over a period of 200 million years will have been consumed, at a rate of a million's worth per year. We will have depleted much of the Earth's priceless reserves of chemicals which would surely be of much value to our descendants. We have stolen from our children's children the ability to turn night into day. I call that daylight robbery.

 

NB: Sir John Templeton, a businessman and philanthropist, died on 8 July. His Foundation has recently published a collection of 13 short essays on the theme ‘Does science make belief in God obsolete?'. I hope to make this the subject of a future column.

 

Further information:

Global Monitoring Division, National Oceanic & Atmospheric Administration

Center for the Study of Carbon Dioxide and Global Change

'Does science make belief in God obsolete?' - free download