Global or planetary warming is the phenomenon of the increase, on a global scale and over a number of years, of the average temperature of our oceans and atmosphere. Today, most* scientists attribute the causes of global warming to human activity, particularly gas emissions and the greenhouse effect. The major climatologists warn us that this warming trend that they have observed over the last 25 years (since the end of the 20th Century) threatens to modify our climate and cause major damage: heightened sea levels, increased and more intense extreme weather situations (droughts, floods, cyclones), the destabilization of forests, fresh water shortages, agricultural hardship, desertificaion, reduced biodiversity, and the spread of tropical disease, etc.

In order to prevent and slow down this global warming, the G7 created the IPCC (Intergovernmental Panel on Climate Change) in 1988. It is now an organ of the UN and boasts more than 3000 researchers from over 140 states. After the AR4 report by this group of experts on climate change (IPCC 2007), which was approved by all nations, including the US, 46 countries have committed to fight against countries that do not reduce their greenhouse gas emissions. The countries concerned include the US, Russia, India, and China.