Carbon dioxide (CO2) is a naturally occurring greenhouse gas, and the greenhouse effect a natural phenomenon by which certain gases (the so-called “greenhouse gases”) retain part of the heat that the Earth emits, making it indeed habitable for man.
However, the amount of CO2 emitted into the atmosphere by man since the advent of the industrial era has reached unprecedented levels.
In May 2013, the WWF issued an warning indicating that the amount of carbon dioxide (CO2) present in the atmosphere has now exceeded 400 parts per million (from a reference value of approximately 190-290 parts per million). The data, made public through research by the Scripps Institution of Oceanography, suggests we are returning to the climate and habitat of the Eocene Epoch, in which humans had still not populated the planet (National Center for Atmospheric Research – NCAR, 2011).