Are we to blame? And will the world be warmer?
There is no doubt that humans are to blame for the increase in atmospheric greenhouse gas concentrations, but does that explain the rise in temperature? Very likely, says a UN worldwide body - the Intergovernmental Panel on Climate Change (IPCC) - which brings together climate scientists and other experts. In its last landmark report in 2001, the IPCC stated that "most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations".
The IPCC also made some worrying predictions. By 2100 temperatures could rise by between 1.4°C to 5.8°C. Whilst the low end of this spectrum would be survivable, the high end would lead to almost unimaginable changes in the planetary system. For comparison, during the last ice age, when glaciers reached Manhattan and southern England, global temperatures averaged only 5°C cooler than now. Even a moderate temperature rise would cause rising sea levels, shifting weather patterns and an increase in the frequency of extreme weather events resulting in massive traumas both for human populations and for nature.