Department of Energy and Climate Change

Climate is the average weather experienced over a long period. This includes temperature, wind and rainfall patterns. The Earth’s climate is not fixed, and in the past has changed many times in response to a variety of natural causes. In the last 100 years however, the Earth has warmed by 0.74°C and by around 0.4°C since the 1970s.

 

The 2007 Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) leaves no doubt that human activity is the main cause of the warming observed over the last 100 years, particularly over the last 50 years.

 

The main human influence on global climate is the emission of so called greenhouse gases, such as carbon dioxide (CO2), methane and nitrous oxide. As these gases build up in the atmosphere, they strengthen what is known as the “greenhouse effect”. At present, over 30 billion tonnes of CO2 are emitted globally each year by burning fossil fuels, and another 7 billion tonnes by changes in land use, mainly deforestation. These gases are now concentrated in the atmosphere at levels not seen for at least the past 650,000 years.

 

According to the AR4, average global temperatures are likely to rise between 1.1°C and 6.4°C (with a best estimate of 1.8 to 4°C) above 1990 levels by the end of this century, depending on our future greenhouse gas emissions. This will result in global sea levels rising by between 20 and 60cm by the end of this century, continued melting of ice caps glaciers and sea ice, significant changes in rainfall patterns and intensification of tropical cyclones such as hurricanes.

 

Globally, there will be more intense heat waves, droughts and flooding. There may be severe problems for regions where people are particularly vulnerable to changes in the weather. Food shortages and the spread of disease are commonly predicted. The social, environmental and economic costs of climate change could be huge if no global action is taken to reduce emissions. You can find out more about the costs of climate change in the recent Stern report.

 

While climate change presents a significant challenge to the UK and the world, there are also some enormous opportunities if we are willing to take action. Climate change affects us all – and we can all be part of the solution. Government, business and individuals all have a part to play, and together we can all benefit if we rise to the challenge of climate change.