Could we meet a 1.5°C target with negative emissions technology?

20 Oct 2016

Negative emissions technology, such as bioenergy with carbon capture and storage, was the topic at issue at a conference last month on limiting global temperature rise to 1.5°C, reports Sam Hampton, UKERC Researcher and PhD Student at the University of Oxford.

Last month, the University of Oxford’s Environmental Change Institute held a conference responding to the ambitious target set by the Paris Agreement of limiting global temperature rise to 1.5°C.

The conference saw debate over the size of the ‘carbon budget’ to stay below 1.5°C, and how long it will take to exhaust it. Pete Smith from the University of Aberdeen, pointed out that 80% of global models apply negative emissions technologies (NETs) extensively to achieve 1.5°C, despite technical, economic, social and political uncertainties.

NETs turned out to be a controversial topic, raising technical, ethical and political challenges. Kevin Anderson, University of Manchester, used Twitter to express his concern that the attention given to NETs was distracting from mitigation efforts: ‘we’ve had offsetting; CDM; CO2 trading, now BECCS/NETs/SRM, anything but actual mitigation’. (The acronyms refer to the clean development mechanism, bioenergy with carbon capture and storage, and solar radiation management.)

The key question for discussion was the role of technology in helping to reduce, and even reverse emissions, in order to meet the 1.5°C goal.

David Keith from Harvard University addressed the idea of solar radiation management (SRM) – such as the use of artificial stratospheric aerosols to block the sun’s rays – hypothesising that if the technology could be used to offset half of the growth in human-caused radiative forcing, it could substantially reduce the aggregated risks of climate change.

Stuart Haszeldine from the University of Edinburgh and Henrik Karlsson from Biorecro in Stockholm, argued the case for capture and storage (CCS), saying it is already proven at industrial scale, e.g. Norway’s Sleipner project and the facility at Decatur, Illinois. Both Haszeldine and Karlsson concluded that ‘strong, consistent’ policies are required to encourage private investment in CCS.

Zara L’Heureux described work from the Centre for Negative Carbon Emissions in Arizona, demonstrating the feasibility of direct air capture for carbon sequestration. The project aims to develop small scale one-tonne-per-day storage facilities, though doubts remain over the technology’s cost reduction potential, she said.

Janos Pasztor, Senior Advisor to the UN Secretary-General on Climate Change, expressed views on bioenergy with carbon capture and storage (BECCS): “Sometimes I wonder if BECCS is just a fudge factor to make our models reach 1.5°C or 2°C, or whether it’s a real prospect.”

As well as technical questions on the feasibility of BECCS, many contributors highlighted the importance of governance, equity and social acceptability. Peter Frumhoff, Director of Science & Policy at the Union of Concerned Scientists, worried about the uneven regional impacts of a future world with swathes of agricultural land dedicated to energy production.

This is an abridged version of an article originally published in Carbon Brief. Sam Hampton is currently undertaking PhD studies at the University of Oxford, addressing the role of energy policy in influencing practices and services.