People talk a lot about weather. That's not surprising when you consider the impact it has on our mood, how we dress or what we eat. Climate however is not the same as the weather. It is the average pattern of weather for a particular region over a long period of time. The classical period is 30 years, as defined by the World Meteorological Organization.

Climate change is a long-term change in the statistical distribution of weather patterns over periods of time that range from decades to millions of years. The climate has and will always vary for natural reasons. However, natural causes can explain only a small part of the warming observed in recent decades. The overwhelming majority of scientists agree that it is due to rising concentrations of heat-trapping greenhouse gases in the atmosphere caused by human activities. The United Nations have created The Intergovernmental Panel on Climate Change (IPCC), consisting of a group of scientists, in order to evaluate the risks of climate change (caused by human activities).

The impacts of climate change are severe: Polar ice caps are melting and sea levels rising, and extreme weather phenomena like heat waves, floods, droughts and forest fires are becoming more common. All these events have a big human and economic cost. Nature is under threat. Many animals and plants will not be able to cope with higher temperatures and changes to their natural habitats. Developing countries, and the poorest people who live in them, are the most vulnerable to climate change.