Global warming

It certainly hasn't reached Bournemouth yet. Although bright and breezy you need a coat to go out today. But it got me thinking about how much humans can do to alter the climate. I am well aware that the vast majority of scientists believe that greenhouse gasses are to blame for changes in temperature and that natural disasters like Hurricane Katrina are laid at the door of gas guzzling SUVs. But is the evidence convincing? (For a different view of global warming go to http://www.co2science.org)

The scientist in me is wary of stuff that makes headlines in newspapers. Publicity equals money for scientists and scare stories sell newspapers. Hardly anything that is reported in the press about science is accurate. It is oversimplified, sexed-up, exagerated and always I hear someone cranking the handle of self interest.

Two things make me wary. First is the short obervation period. We know that climate does fluctuate. In Roman times there were vinyards in Britain. In the 17th century the River Thames froze over. Although a graph of the rates of fluctuation could be constructed and a varying rate of change could be measured, I suspect that it is too soon to work out whether the change is a temporary blip or a permanent one.

Second is buffering. All systems seem to have a built in homeostatic control. In the human body, for example if the blood gets too acid we start breathing heavily to blow off carbon dioxide which raise our pH. If carbon dioxide levels in the atmosphere rise then plants are encouraged to lay down carbohydrates by photosynthesis. There is a huge reservoir of blue green algae in the Pacific Ocean that is blooming becuase of raised carbon dioxide. Now whether this sort of buffering is or will exert a corrective effect I do not know, nor do I know of anybody working on it.

I can see that there is a case for reducing polution in the atmosphere. Since burning of coal was abolished in Britain it is a much cleaner place and chest infections are fewer. It is clearly technically possible to obtain energy in a less polluting way, and it is technically possible to stop being so profligate in our waste of energy. At the moment our reason to do so is to respond to the propaganda that governments and NGOs pepper us with. It won't work. We won't believe that governments are serious unless they make it economically advantageous for us to conserve fuel. A massive hike in the tax on gas would do it. A concerted effort to raise the tax on air travel would do it. Tax breaks for nuclear power or clean coal technology would do it.

The current fashion is for hybrid vehicles. These cars that run on petrol on long runs but swich to electricity in towns are encourages by tax rebates, low road fund licenses, and freedom from the London congestion charge. However, we should ask ourselves rather whether we really need a new car. The environmental cost of building one is greater than teh environmental savings from running one. The world would benefit more from having one fewer car factory than from a slightly greater mpg. A far better buy would be a second hand diesel BMW. They will match the mileage of a Toyota or Honda hybrid, last for 200,000 miles and run on old cooking fat when the oil wells run dry.