WHAT IS CLIMATE CHANGE?
Without a phenomenon known as the greenhouse effect the temperatures on earth would be much colder. Gases in the earth’s upper atmosphere create the greenhouse effect. These gases trap heat and ensure that the temperatures on earth can sustain life.
The main greenhouse gas (by volume) in the atmosphere is carbon dioxide. It is also the greenhouse gas produced in the greatest quantities. Carbon dioxide accounts for 85% of the UK’s total greenhouse gas emissions. Methane is another powerful greenhouse gas (20 times more powerful than carbon dioxide) but it is produced in smaller quantities.
Levels of carbon dioxide in the atmosphere have shown a marked increase since the industrial revolution and they are continuing to rise.
Crown Copyright 2009, The Met Office
Global temperatures are also increasing. Average global surface temperatures have increased by 0.15oC per decade since the mid-1970s. Warming has been unprecedented over the last 50 years and the 17 warmest years have occurred in the last 20 years.
Carbon dioxide is mainly emitted from burning fossil fuels for energy; i.e. to power our homes and offices and to provide fuel for transport. However, land changes such as deforestation also add a significant amount annually.
Increasingly scientists are concluding that the rise in global temperatures is due to human activity. The Intergovernmental Panel on Climate Change (IPCC) reported that there is a 90% probability that global warming is linked to human activity.
Even if no more greenhouse gases were added to the atmosphere there would still be changes to the earth’s climate over the coming decades. This is due to the increased concentrations of carbon dioxide in the atmosphere that have already taken place.
The changes to the climate will be more pronounced in some parts of the world than others. The Polar Regions are already experiencing significant changes.
Although the climate has always changed, the changes over the coming decades are likely to be more extreme than human civilisation has faced before. The picture is complex, however; across the world there is likely to be a rise in annual temperatures, and polar ice caps will melt leading to a rise in sea levels.
The changes are likely to have a major impact on agriculture and water supply, and many coastal and low lying areas will be threatened by flooding.
This situation could be compounded by an increase in the amount of intense storms and hurricanes.
If you are interested in finding out more on the science of climate change, the following websites are useful: