Global Warming -The State of Play

An article on by Brian Sheen

That there have been changes in the world's climate within living memory is indisputable. It is just the weight placed by the various authorities on the different elements that cause these changes that is questioned by some.

The parts we cannot influence.

Solar Output - Variations in the Solar Constant.

In 1980 NASA using the Solar Maximum Mission Satellite started to measure the output from the Sun. Over a period of six years it declined by 0.1 % and then started to rise again. Although small in percentage terms it is a significant factor in the Earth's climatic change and changes in phase with the 11 year Sun Spot Cycle. We are now just past Sun Spot Maximum.

Milankovitch Cycles.

In the 1920's Milankovitich showed that the Earth's orbit changes over a period of time. As we know the orbit is elliptical, but over a period of 100,000 years the shape of the orbit becomes more circular before returning to its elliptical form. Every globe shows that the Earth is inclined at an angle of 23.5 degrees from the vertical, however over a period of 41,000 years this varies between 21.5 and 24 degrees. A further change is caused by the fact that the Earth wobbles on its axis like a spinning top, this is called precession and has a period of 26,000 years. These changes alter the amount of sunlight falling on the Earth. Although at the time not enough was known about climate changes throughout the ages scientists now realise that he did indeed discover the cause of at least 60% of the climatic fluctuations. His cycles have been shown to correspond with ice ages and inter glacial periods.

Today's story.

In recent years scientists have become increasing aware that the Earth is warming up and that the temperature increase relates directly to an increase in the amount of carbon dioxide in the atmosphere.

A Mini Ice Age?

One unexpected outcome could be a drop in temperature, a mini ice age. This is due to the fact that the ocean currents that carry warm water from the tropics to our shores and beyond. These could melt the Arctic Ice to such an extent that cold water flowing south could break the Gulf Stream or Atlantic Conveyor bringing about a dramatic drop in temperature. The Gulf Stream transports more energy northwards every hour than would be produced by burning five billion tonnes of coal.)

The Part we can Influence

What individuals can do, although it might appear that we are powerless to affect the total amount of emissions we can to something to help ourselves. We can switch off TV sets when not in use, we can run our houses at lower temperatures, and run smaller cars and recycle rather than dump many of our products.

However it is down to Governments to put in place policies to reverse the sharp increase in consumption of fossil fuels and keep carbon dioxide levels from rising.

Can anything be done? Actually a significant proportion of the excess carbon dioxide can be locked up in plants and trees so halting our slide to a much more stormy world.

The Challenge

The challenge facing all of us, post Bonn, in the next few years is to persuade the governments in the wealthy parts of the world to plant enough trees in the tropical continental countries to prevent tropical island nations from disappearing beneath the waves. Such a policy will, however, only give us a breathing space while we put our house in order.

For those wishing to learn more about the factors involved in to global warming should visit the Gaia Energy Centre in Delabole, Cornwall.