When the Greenhouse effect becames global warming ?
In the last sixty years the amount of carbon dioxide emitted to the atmosphere by humankind, mainly due to the increase of fossil fuel usage, increased the concentration of this gas in the atmosphere from 280 ppm (particles per million), in the pre-industrial era, to 365 ppm in 1995 (KEELING & WHORF, 1998). Nowadays the atmospheric carbon concentration is in 379 ppm, according to the lasts measures done in the Mauna Loa Station, in Hawaii (Martins, 2004). The Intergovernmental Panel on Climate Change (IPCC), foresaw in 1996, that the global CO2 emissions could increase from 7,4 GtC/year (2007 figures), to around 26 GtC if emission reduction measures are not to be adopted. The alarm sounded when the IPCC reports were published in the first semester of 2007. The document foresees that the planet’s average temperature increases around 1.8ºC and 4ºC until the end of this century. An increase of 2ºC in the globe’s mean temperature from 1980 to 1990 could mean the vanishment of 30% of the pl
