Mere Cleaning of Energy Supply Not Sufficient to Achieve Paris Agreement Goals

Fossil fuels are used for Transporting goods, manufacturing products, and heating buildings. The authors of a new study have stated that the lack of critical change at present in these sectors will lead to a “lock-in” of increased emissions of carbon dioxide (CO₂) for several decades.

The objective of the Paris Agreement, which was embraced in 2015, is a global warming of well below 2 °C, and prospectively 1.5 °C, to prevent the grave effects of climate change. Majority of the existing plans to achieve this goal are reliant on making the production of energy generation greener, for instance, by substituting natural gas- and coal-fired power plants with solar and wind power.

Green Energy Alone Not Enough

However, the innovative study, reported in the Nature Climate Change journal on June 25, 2018, by researchers from Imperial College London, indicates that the Paris Agreement goals cannot be achieved merely by cleaning up energy supply. Rather, CO₂ savings have to be made even in the transport, industry, and building sectors.

For instance, transport is dependent on the internal combustion engine, in which fossil fuels such as petrol are burned. The CO₂ emissions from road transport and personal cars can be reduced by electric car engines; however, the same engine types cannot be used in the place of the engines used in aviation or shipping.

The authors say that lack of efforts in these sectors will lead to heavy dependence on removal technologies in which CO₂ is extracted from the atmosphere, which are unreliable and unverified on a large scale.

Ensuring that global warming is kept within safe bounds requires us to stop emitting carbon dioxide into the atmosphere. Nobody expects this to happen overnight, but decisions made today matter much longer than often appreciated.

Dr Joeri Rogelj, Grantham Institute—Climate Change and Environment, Imperial

“Residual” CO₂ Emissions

Infrastructure that is dependent on carbon-based energy, such as the majority of freight transport and the production of concrete, is often developed to last for several decades. This indicates that without combined efforts to modify these systems at present, they will persistently emit CO₂ for several decades from now. Such “residual” CO₂ emissions have a huge impact on future predictions.

The Paris objectives of maintaining global warming well below 2 °C relates to the fact that there is a restricted remaining “budget” for the amount of CO₂ that is safe to be released. For instance, to maintain global warming to just 1.5 °C, various research works propose we may only be permitted to emit as low as 200 Gigatons of CO₂, which is far from the 4000 Gigatons of CO₂ that would be emitted if prevalent trends persist.

Uncertain and Potentially Risky Technologies

This has led to concerns about the growing dependence on unreliable and potentially hazardous technologies for so-called negative CO₂ emissions, such as carbon capture and storage (CCS) or bioenergy plantations.

The team worked within distinctive carbon budgets and modeled policy action scenarios for climate change to ascertain ways for meeting the targets.

We found that even with enormous efforts by all countries, our calculations show that residual fossil carbon emissions will remain at about 1000 Gigatons of CO₂. This seems to be a lower end of what can be achieved with even the most stringent climate policies, because much of the residual emissions are already locked into the system due to existing infrastructures and dependencies on fossil fuels.

Dr Gunnar Luderer, Potsdam Institute for Climate Impact Research, Germany

Ramping up Ambitions

The researchers discovered that the ambitious goal of 1.5 °C for 2100 would relate to removal of at least 600 Gigatons of CO₂ required under the assumptions of their study, even though other recent studies to which Imperial College London scientists contributed demonstrate this could be far less.

While it may still be difficult to determine the exact remaining CO₂ budget for 1.5 °C, one thing is very clear: ambitions to reduce fossil fuel emissions have to be ramped up substantially and soon to keep doors open to meet the Paris targets.

Dr Elmar Kriegler, Potsdam Institute for Climate Impact Research, Germany

This study was funded by the European Union’s Seventh Programme FP7/2007-2013 under grant agreement no. 308329 (ADVANCE) and also the Horizon 2020 Research and Innovation Programme under grant agreement no. 642147 (CD-LINKS).