Climate Change: An introduction

The Earth’s climate has been constantly changing throughout its history so this change is not a new phenomenon. As far as scientists can tell, these changes took place slowly and often over millions of years.

In the distant past in different places it has been hotter, cooler, drier or wetter. The global atmosphere also contained significantly different proportions of nitrogen, oxygen and other gases.

It is partly as a result of such changes that new species have evolved and others become extinct and polar ice caps have waxed and waned. Since the Industrial Revolution, and especially in the last few decades, climate change, and the global warming that it produces, has been proceeding at an unprecedented rate.

Why is there so much concern now about climate change?

The burning of fossil fuels is one of the main causes of climate change via the release of the greenhouse gas carbon dioxide (CO2) into the atmosphere. Since the advent of the industrial age the amount of CO2 and other greenhouses gases released into the atmosphere has substantially increased (threre has been a 25% increase in CO2 in the last 40 years).

At the same time increased affluence in developed countries and a growing global population have led to greater consumerism and more land being cleared for agriculture reducing the planet’s ability to absorb the extra carbon via the oceans and growing vegetation.

The result is that the global average surface temperature of the planet is rising, apparently inexorably, as the greenhouses gases in the atmosphere trap more solar energy.

The earth’s climate system is complicated with multiple crosslinking of components and feedback loops. Today the main obvious impacts of global warming include rising sea level, acidification of the oceans and pressures on living organisms.

Scientists expect sea level to have risen by at least 30-40 cm during this century. Many species are having to find new habitats or adapt to change; some are becoming extinct. Increasingly, extreme weather events (floods, droughts, heat waves and storms) across the globe are also being attributed to global warming.

What should our response be to global warming?

Therefore sources of energy that reduce our reliance on fossil fuels, such as wind, waves, tides and the sun should be explored and, where feasibility assessments show them to be effective, they should be exploited.

The alternative approach of burning fossil fuels using equipment to capture the carbon dioxide before it escapes to the atmosphere has yet to be shown to be technically feasible on a commercial scale.



1: Department of Energy and Climate Change website
2: Link to Hampshire County council climate change page which includes many links to useful websites
3: Projected climate change models (South East England selected). By clicking into the overview and maps it is possible to see how precipitation and other factors could change depending on the model assumptions used.
4: Intergovernmental department on Climate Change – A range of publications showing latest thinking on climate change
5: Open University free resource
a) Study module focussing on greenhouse gas emissions and what individuals can do to reduce their impact
b) Study module focussing on the science behind climate change
6: Winchester Action on Climate Change  for relevant WinACC publications and links to informative sites.