2°C climate target is half of what is needed, say scientists – ‘CO2 emissions have to be cut twice as much as if we only want to meet the two degree target’Posted by Jim at Saturday, July 06, 2013
By Tim Radford for Climate News Network, part of the Guardian Environment Network
5 July 2013
(The Guardian) – Governments that agreed to try to restrict global warming to a rise of no more than 2°C may have set themselves the wrong target, according to Swiss scientists.
Marco Steinacher from the University of Bern and colleagues report in Nature that the cuts in carbon dioxide emissions necessary to achieve this limit to rising temperatures won't stop sea level rise, won't halt the acidification of the oceans and won't repair the losses in agricultural productivity.
They argue that a simple notch on the mercury thermometer 2°C above the pre-industrial average is not ambitious enough. The climate system involves more than just global mean atmospheric temperature: it also depends on the atmosphere's interactions with the hydrosphere, the biosphere and the geosphere.
To keep the planet habitable, governments have also committed themselves to save biodiversity and at the same time to deliver food security for the 10 billion citizens who may populate the Earth later this century. All these targets will together require much deeper cuts in emissions.
"Therefore, temperature targets alone are unable to comprehensively limit the risks from anthropogenic emissions", they warn bluntly.
"When we consider all targets jointly, CO2 emissions have to be cut twice as much as if we only want to meet the two degree target." [more]