Greenhouse effect

Greenhouse gases in the atmosphere absorb the energy emitted by the Earth in the form of infrared radiation and pass it as heat to all gases in the atmosphere. As a result the lower atmosphere and Earth’s surface get warmer. Initially, this so called greenhouse effect made our life on Earth possible (without the greenhouse effect and the atmosphere, the average Earth’s surface temperature would be as low as -18 °C) and have always played a key role in regulating Earth’s temperature. According to the scientists there is a strong correlation between the changes in concentration of greenhouse gases in the atmosphere and the temperature changes throughout the whole Earth’s history. But since the beginning of the industrial era and the massive deployment of fossil fuels, the concentration of these gases raised to an unprecedented level and the temperature change starts to seriously undermine the global ecosystem.

"Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG [greenhouse gases] concentrations. It is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent (except Antarctica)”, states the Fourth Report of the UN Intergovernmental Panel on Climate Change (IPCC) . The report also stresses that “anthropogenic warming could lead to some impacts that are abrupt or irreversible (...)”.

Carbon dioxide, methane and nitrous oxide concentrations increased markedly since 1750, the time when industrial production began to develop. The global atmospheric concentration of carbon dioxide has increased from a pre-industrial value of about 280 ppm (parts-per-million) to the current 379 ppm: in 2005 it exceeded by far the natural range over the last 650,000 years (180 to 300 ppm) as determined from ice cores. In addition, during the last decade the annual carbon dioxide concentration growth rate accelerated profoundly: over the period of 1995–2005 the increase was larger (average: 1.9 ppm per year) than it has been since the beginning of continuous direct atmospheric measurements (1960–2005 average: 1.4 ppm per year).

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