CO2 (carbon dioxide)

Greenhouse effect, global warming, rising sea levels, melting ice floes or glaciers... these are all expressions that have become part of everyday language as a result of alarmist statements in the media.

The international conferences of Rio (1992) and Kyoto (1997) (COP3 – 38 signatory countries) mark a determination to reduce atmospheric pollutants. In 1997, the Kyoto Protocol required the 38 signatory countries to reduce their greenhouse gas emissions by 5.2% by 2008-2012. Against this backdrop, the European Union issued a directive, adopted on October 13, 2003, providing for emission quotas and penalties for exceeding commitments. France has reduced its CO ₂ emissions by around 15% and 6% respectively compared with 1990 and 2010. . In December 2015, the COP21 (21st Conference of the Parties), bringing together 195 countries, held in Paris, enabled discussion between States and generated an agreement text with, in particular, a 2°C limit on temperature rise in 2100. This implies a drastic reduction (-25% by 2030) of greenhouse gases (GHGs) present in emissions due to human activity.

Based on French data, the main greenhouse gas (GHG) molecules are listed and defined. They include water vapor (55%), carbon dioxide (CO ₂ ) (39%), methane (CH ₄ ) (2%), ozone (O ₃ ) (2%) and, to a lesser extent, nitrous oxide (N ₂ O) (2%), nitrous oxide (N ₂ O) 2% and, to a lesser extent, halocarbons (chlorofluorocarbons (CFCs), freon, perfluoromethanes) and sulfur hexafluoride (SF6).