Since 1751, approximately 356 billion metric tonnes (gigatons) of carbon has been released into the atmosphere from burning fossil fuels (and cement production, which accounts for about 5% of global CO2 emissions because CO2 is a by-product of converting calcium carbonate into lime). Half of all fossil fuel emissions have occurred since 1980. (Biogeosciences, 9, 1845-1871, 2012)
In 2010, at UN climate talks in Mexico, 167 countries, together responsible for more than 87% of global carbon emissions, committed to prevent average temperatures rising more than 2˙C above pre-industrial levels. “Two degrees” has been adopted as the threshold which we must not pass.
To keep temperature rise within 2˙C, climate scientists calculate that human activity can add no more than another 565 gigatons of carbon dioxide into the atmosphere by 2050. At present rates, (31 gigatons globally during 2011 and rising) this figure will be reached by 2028. (Bill McKibben, Rolling Stone 2/08/12)
Computer models indicate that current trends in emissions put us on track for an average temperature increase of 6˙C by the end of this century – a devastating change. The 2012 Report for the World Bank by the Potsdam Institute “Turn Down the Heat” predicts that current emissions put us on track for a temperature increase between 4˙ and 6˙C by 2100.
Target Concentration for CO2 in the atmosphere:
Since 1751, approximately 356 billion metric tonnes (gigatons) of carbon has been released into the atmosphere from burning fossil fuels (and cement production, which accounts for about 5% of global CO2 emissions because CO2 is a by-product of converting calcium carbonate into lime). Half of all fossil fuel emissions have occurred since 1980. (Biogeosciences, 9, 1845-1871, 2012)
In 2010, at UN climate talks in Mexico, 167 countries, together responsible for more than 87% of global carbon emissions, committed to prevent average temperatures rising more than 2˙C above pre-industrial levels. “Two degrees” has been adopted as the threshold which we must not pass.
To keep temperature rise within 2˙C, climate scientists calculate that human activity can add no more than another 565 gigatons of carbon dioxide into the atmosphere by 2050. At present rates, (31 gigatons globally during 2011 and rising) this figure will be reached by 2028. (Bill McKibben, Rolling Stone 2/08/12)
Computer models indicate that current trends in emissions put us on track for an average temperature increase of 6˙C by the end of this century – a devastating change. The 2012 Report for the World Bank by the Potsdam Institute “Turn Down the Heat” predicts that current emissions put us on track for a temperature increase between 4˙ and 6˙C by 2100.
http://climatechange.worldbank.org/sites/default/files/Turn_Down_the_heat_Why_a_4_degree_centrigrade_warmer_world_must_be_avoided.pdf
http://www.climateconsent.org/pages/carbonmaths.html