Climate Change Overview 

  CarbonNeutral Company - October 06

Human induced climate change – which results from increased ‘greenhouse’ gases – is the greatest environmental threat of this century.

The greenhouse effect - some basics

The earth, like our own bodies, cools or warms until the energy ‘inputs’ from warming (from the sun, for example) are in balance with energy lost through cooling. Greenhouse gases are emitted to the atmosphere when we burn fossil fuels to generate electricity or heat, or to power engines for travel. These gases (principally CO2) trap some of the sun’s energy within our atmosphere – like a greenhouse roof – increasing the temperature at which the earth achieves energy balance.

The root cause?

The main greenhouse gas is carbon dioxide (CO2). This accounts for about two thirds of the human induced warming effect. Methane, nitrous oxide and other gases account for the remaining third.

CO2 levels have risen one third since the industrial revolution and are set to double in the next 100 years; temperatures which have varied less than 1 degree since the dawn of civilisation, are projected to rise between 1.4 and 5.8 degrees centigrade over the next 100 years - depending on how mankind chooses to evolve civilisation.

The impact?

Swiss re, the reinsurance company, provides an economic impact indicator: losses from natural disasters are doubling approximately every 10 years and could reach about $150 billion in 10 years. In a study of the summer of 1995 in England and Wales, which was about 1.5C warmer than average, it was estimated that net economic losses were about £1.5billion.

The consensus from the 2005 conference of scientific experts was that a temperature increase of 2C above pre-industrial levels may be a threshold which triggers melting of the Greenland ice cap. To have a high probability of not exceeding this 2C limit, atmospheric CO2 concentrations should stay below 400ppm. This may be reached in 10-15 years at the current rate of increase.

Those least able to cope with climate change – developing countries – are likely to be among the most affected. It will further reduce access to drinking water, negatively affect the health of those living in poverty, and will pose a real threat to food security in many countries. If the Greenland ice sheets melt, the sea level rise would be so dramatic that the map of the world would change substantially.