The greenhouse effect
The earth is surrounded by a layer of gases which act like the glass walls of a greenhouse. These gases let the sun’s rays enter, but stop much of the heat from escaping. This is a natural process, and it’s these ‘greenhouse gases’ (mainly carbon dioxide and water vapour) that keep the planet warm enough to sustain life.
However, as humans cause more greenhouse gases to be released into the atmosphere, the greenhouse effect becomes stronger. More heat is trapped and the earth's climate begins to change unnaturally.
In the UK, around:
4 per cent of emissions come from industrial processes
7 per cent are from agriculture – for example methane emissions from livestock and manure, and nitrous oxide emissions from chemical fertilisers
21 per cent are from transport
65 per cent come from the use of fuel to generate energy (excluding transport)
40 per cent of emissions in the UK are the result of decisions taken directly by individuals. The biggest sources of emissions for most people are likely to be:
energy use in the home (the main use is heating)
Other things in people's homes contribute to climate change indirectly. Everything, from furniture to computers, from clothes to carpets, uses energy when it is produced and transported – and this causes emissions to be released.
The 1990s was the warmest decade in central England since records began in the 1660s. Summer heatwaves are now happening more frequently and in winter there are fewer frosts.
Globally, over the past century, the average temperature of the atmosphere near the earth’s surface has risen by 0.74 degrees Celsius. Eleven of the 12 hottest years on record occurred between 1995 and 2006.
Changing sea levels and temperatures
The sea level around the UK has risen
UK coastal waters have warmed by about 0.7 degrees Celsius over the past three decades. In addition, the average sea level around the UK is now about 10 cm higher than it was in 1900.
Globally, the sea level could rise by 18 to 59 cm by the end of the century. Rising sea levels would swamp some small, low-lying island states and put millions of people in all low-lying areas at risk of flooding.
You can use Google Earth to see how climate change could affect temperatures and ice caps over the next century. Google Earth also lets you view the loss of Antarctic ice shelves over the last 70 years.
Since rain records began in 1766, the amount of winter rainfall in England and Wales has risen. Over the last 45 years it has also become heavier; in 2000, UK flooding was the worst for 270 years in some areas. Flood damage now costs Britain about £1 billion a year.
Globally, climate change means that extreme weather events – like floods, droughts and tropical storms – will become more frequent and dangerous.
Food and water
As temperatures increase and rainfall patterns change, crop yields are expected to drop significantly in Africa, the Middle East and India.
Water availability for irrigation and drinking will be less predictable because rain will be more variable. It is also possible that salt from rising sea levels may contaminate underground fresh water supplies in coastal areas. Droughts are likely to be more frequent. Up to three billion people could suffer increased water shortages by 2080.
With rising temperatures, diseases like malaria, West Nile disease, dengue fever and river blindness will shift to different areas. It is predicted that
290 million additional people could be exposed to malaria by the 2080s.