By Ed King
A global price of $30 per tonne of carbon dioxide needs to be introduced urgently if the worldâs governments are serious about avoiding a 2Â°C warming target.
Thatâs the view of Keywan Riahi, Energy Program leader at the International Institute for Applied Systems Analysis in Austria, and one of the authors of a report published today in Nature analysing the potential costs of climate change mitigation.
Riahi told RTCC their research indicates a $30 price signal would give a 60% chance of limiting warming below the agreed UN limit of 2Â°C warming above pre-industrial levels.
But the price would rise to $100 per tonne of carbon dioxide by 2020 if no effective mitigation action is taken between now and the end of the decade.
âThe report doesnât leave me depressed but it does indicate that the pace at which climate negotiations are moving towards an agreement is simply too slow,â he said.
âThere is some movement but it is really critical to achieve some agreement over the next year otherwise the long term objective which has been agreed by most countries will be out of reach.â
Despite a growing number of carbon trading schemes around the world, there is currently no global price for carbon.
At the recent UN climate talks in Doha more than 100 companies including Unilever, Shall and Swiss Re urged governments to consider agreeing on a price, arguing that it would drive investment in the low carbon sector.
At the start of 2013 the price of a tonne of carbon in the EU was 7.72 Euros, just over $10.
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Energy efficiency measures would give countries more âheadroomâ to manoeuvre, and Riahi says if consumption were maintained at 2012 levels a $30 carbon price would offer an 80% chance of avoiding 2Â°C of warming.
At the 2011 UN climate talks leaders agreed to work on a legally binding climate deal to come into effect in 2020, but there are no plans to effectively contain global emissions over the next decade.
Scientists say 2Â°C is a threshold beyond which climate change would become dangerous and unpredictable.
Should action be delayed until 2030 the report says the odds of avoiding 2Â°C fall plummet, and become far more expensive.
âUltimately, the geophysical laws of the Earth system and its uncertainties dictate what global temperature rise to expect,â said Joeri Rogelj, lead author on the paper.
âIf we delay for twenty years, the likelihood of limiting temperature rise to 2Â°C becomes so small that the geophysical uncertainties donât play a role anymore.â