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Carbon Brief Staff

Carbon Brief Staff

03.12.2013 | 4:00pm
ScienceCurrent UN climate targets could push two degree limit out of reach
SCIENCE | December 3. 2013. 16:00
Current UN climate targets could push two degree limit out of reach

Nations breathed a sigh of relief when, after a fractious few weeks, negotiators were able to find any agreement at all at UN climate talks at Warsaw. But in the continuing absence of a global agreement, new research finds that the compromise – voluntary pledges to reduce emissions until 2030 – won’t be enough to meet global climate targets. 

According to agreements reached at earlier climate talks at Copenhagen and Cancun, countries have made individual voluntary pledges to cut their emissions by 2020, expecting to establish an international agreement by 2030. 

The research, from a group of 13 international  institutions, led by the International Institute for Applied Systems Analysis (IIASA) and the Postdam Institute for Climate Impacts Research, follows through the countries’ targets to 2030. It finds they will result in much higher emissions – meaning the short-term delay could have serious long-term implications. 

Giddy heights to deep cuts 

According to the authors, the individual pledges would result in a six to 22 per cent increase in emissions  for the year 2030 – much more than the level needed to start stabilising emissions. While it could still be possible to meet targets starting from those levels, action to significantly reduce emissions much more limited and much more expensive. 

Lead author Keywan Riahi, who heads the IIASA energy programme tells us: 

“Our study clearly shows that the stringency of the policies suggested by the pledges won’t be sufficient to limit emissions to levels that are “safe” by 2030 – and to reach the recognised objective of limiting temperature change to below degrees Celsius.” 

The study uses nine models that simulate the interactions between energy, economics and the environment to explore how easy and cheap it would be to transform current systems to meet low climate targets.  Riahi explains the researchers simulated emissions according to current pledges up to 2030. After that point, they assume emissions are limited severely to meet the carbon budget – the amount of greenhouse gases scientists calculate it will be possible to emit without going over two degrees of warming – for the century.

Riahi says the study is different from others, which have focused on the best time to reduce emissions. Instead, the authors worked from what’s already pledged. He says: 

“The distinct separation of the time-frames helps us to assess the consequences of actions over the short-term for the attainability and costs of long term objectives.”

Limited options

Cutting emissions hard and fast enough after 2030 looks daunting – requiring governments to deploy carbon neutral energy sources three times faster than if we started sooner.  

The researchers say it’s more likely fossil fuel generation will be ‘locked in’ to the system, while technological options to cut emissions will be much more restricted. While it currently might be possible to reach targets without technologies like carbon capture and storage, they will have to be rolled out at large scale after 2030 to achieve the same effect. That will cost much more. 

The window of time is small – from 2030 to 2050 – to close the emissions gap.  The researchers say: 

“That means, for example that new coal power plants built in the next few years may need to be shut down before their natural lifetime-at great cost to investors and governments.”

Riahi explains that to change the system faster and cheaper, international negotiations will have to come up with more stringent targets. He says: 

“Avoiding the risk that low climate goals are getting out of reach, the international negotiations will need thus to agree on emissions targets for 2030 that are more stringent than the pledges. Once we have the target right, we can then think about the policy instruments to implement them.” 

Small window

We’re not short of warnings about how little time remains to keep global temperatures below two degrees.  This latest study illustrates that delaying sufficient action till 2030 will lead to a more expensive, less technologically flexible transformation that leaves us less likely to achieve the target at all. The window of time available to keep below that limit while countries struggling to curb their emissions really is very small.


‘Locked into Copenhagen pledges – Implications of short-term emission targets for the cost and feasibility of long-term climate goals’, Technological Forecasting and Social Change

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