To understand what climate change is, it is important to make the distinction between Climate and Weather. Weather is the temperature, precipitation (rain, hail, snow and sleet) and wind, which we experience on a daily basis and can change hour by hour and day by day. Climate is a longer term average weather in a locality over a thirty year period. This includes temperature, wind and precipitation patterns.

The term climate change refers to the man-made changes that have occurred since the early 1900's. The Earth's climate is not fixed, and in the past has changed many times in response to a variety of natural causes. However, global temperatures have warmed by about 0.75°C on average since around 1900 and by around 0.4°C since the 1970s.

There is a compelling body of scientific evidence suggesting that current and historical anthropogenic (human) greenhouse gas emissions (such as CO₂ from fossil fuel use in power stations, industry, manufacturing, transportation, and methane generated from landfill sites and agriculture) are increasing the concentration of greenhouse gases in the atmosphere. These gases enhance the natural process of the greenhouse effect (opens in a new window) , leading to increasing annual average temperatures. Atmospheric concentration of CO₂ is now higher than at any time in at least the last 800,000 years.

• What is the greenhouse effect?

  The greenhouse effect is the natural process of the atmosphere letting in some of the energy we receive from the sun (ultraviolet and visible light) and stopping it being transmitted back out into space (infrared radiation or heat).

• What are the likely global impacts of climate change?

  Climate change is one of the most serious environmental threats facing the world today and its impact will be felt at a global, national and local level. No matter how effective policies are at reducing greenhouse gas emissions now, the world will still experience a significant degree of unavoidable climate change.

• The changing UK climate

  The UK climate is changing to reflect the global pattern of increasing average temperature.

• Future climate change in the South West

  It is predicted that the South West will experience hotter, drier summers and warmer wetter winters.

• Likely impacts of climate change on Dorset

  Many aspects of our lives and lifestyles will be affected by climate change.