The earth is surrounded with a layer of gases, and energy from the sun enters the earth’s atmosphere by passing through this layer. The earth land and water absorb much of this energy but some is reflected back away from the earth. The rest of the energy remains close to the earth.
Since the industrial revolution, the concentration of these gases including carbon dioxide has increased through out use of fossil fuels and these are becoming trapped in this layer of gas.
This has caused an increase in temperature and scientists agree the average temperature increase must be kept to no more than 20C to avoid the most dramatic and far reaching impacts. This process is generally known as climate change.
There are many examples of how our climate has already changed, both here in the UK and overseas. Research by the Tearfund study estimates there are already an estimated 25 million environmental refugees resulting from floods, storms and rising tides. An increase in temperature has caused the polar ice caps to melt, endangering the habitats of polar bears. In fact, their numbers have declined by 20% in the last 20 years.
In the UK, for example, over the last 40 years our winters have become warmer with more intense rainfall. Over the last 200 years our summers have become drier and hotter, leading to water shortages. The last six summers have been the warmest since records began. The hottest temperature recorded in the UK was 38.5 0C, in August 2003, in Brogdale, Kent.
An increase in rainfall also means our rivers are more prone to flooding. For example the Thames Barrier in London was raised an average of three times a year in it first 18 year of operation. By 2030, it is predicted the Thames Barrage will need to be raised 30 times each year, double its present use.
The changes to our long term weather patterns will affect our health. Research suggests there will be an increase in the cases diseases which are caused by warmer weather including hay fever, cataracts, skin cancer and even tropical diseases such as Dengue fever and West Nile virus. Warmer summers may lead to an increase in food borne diseases. The concentration of ozone will increase and this will lead to more hospital admissions.
On the other hand, warmer winters may mean a reduction in the number of cold related deaths and the number of households experiencing fuel poverty.
In October 2006, Sir Nicholas Stern, advisor to the government published his report on the economic impacts of climate change. The report made several recommendations including that the total cost of unabated climate change would be 5% of the global GDP. In contrast, prompt and substantial actions in the next 10 – 20 years to reduce the impact of climate change would cost only 1% of global economy.