Negative emissions technologies

In May 2017, a number of scientists working in Switzerland addressed the public in a white paper in which they argued that an open societal conversation on the role of negative emissions technologies (NETs) and solar radiation management (SRM) in achieving internationally agreed climate targets was overdue. Their analysis is based on the science underpinning the Paris Agreement. What is Switzerland's position in response to these new policy imperatives aimed at mitigating climate change?

Scientific basis

In the Paris Agreement concluded in late 2015, the international community set itself the goal of limiting average global warming to significantly less than 2 °C above pre-industrial levels while aiming for a maximum temperature rise of 1.5 °C. These goals require a step change in climate change mitigation strategies.

Indeed, the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (2013/14) and the 2018 Special Report on Global Warming of 1.5 °C – which together provided the scientific basis for the Paris Agreement – show unequivocally that global CO2 emissions must be reduced to net zero by mid-century if these targets are to be reached. To the best of our current knowledge, this balance cannot be achieved – even in Switzerland – without negative emissions technologies.

What are negative emissions technologies?

Negative emissions technologies (NETs, also known as 'carbon dioxide removal') permanently remove CO2 from the earth's atmosphere. They intervene in the earth's carbon cycle, directly addressing the root cause of climate change. By contrast, solar radiation management (SRM) aims to reduce the amount of solar radiation reaching the earth's surface. In the past, targeted large-scale interventions in the climate system involving NETs and SRM have been referred to by collective terms such as 'geoengineering' and 'climate engineering'. However, such generic terms have proved misleading given the fundamentally different nature of the two approaches.

The central role of NETs in the latest IPCC reports is a consequence of previous failures in global climate protection. According to (virtually) all model calculations, the Paris climate goals can now only be met by incorporating such technologies. Known emission reduction measures, in the building or transport sectors for example, are no longer sufficient by themselves.

In a recent factsheet entitled 'Reverse emissions or influence solar radiation', the Swiss Academies of Arts and Sciences describe the various approaches and compare the theoretical potential with the costs and risks, as far as these are known. Different approaches are possible depending on national circumstances. In Switzerland, the following activities could have the potential to generate negative emissions on a significant scale:

1. Biological capture of CO2 by photosynthesis and storage in living or dead biomass (enlargement of natural sinks):

  • improved forest management;
  • carbon storage in long-lived wood products;
  • carbon storage in the soil;
  • storage of biochar in the soil.

2. Biological capture of CO2 by photosynthesis with permanent geological storage: biomass is used to generate energy and the resulting CO2 is captured and stored underground (known as 'bio-energy with carbon capture and storage', or BECCS). The storage could take place at a suitable location in Switzerland or abroad. The theoretical underground storage potential available in Switzerland has been estimated.

3. Chemical capture of CO2 from the ambient air with permanent geological storage (known as 'direct air capture with carbon storage', or DACCS).


What role could negative emissions technologies play?

The issues surrounding NETs are complex. One the one hand, there is increasing recognition of the need for such technologies; on the other, there is a risk that their potential may be overestimated, resulting in urgently needed emission reduction measures being deferred or not being implemented at all. Failing to implement such measures would be fraught with risk as, without exception, all the proposed NETs either have not yet been tested in practice or are not ready for deployment on the scale that would be required to affect the climate.

Moreover, many fundamental issues, such as costs or conflicting objectives, have not been sufficiently explored, meaning that the prospects of implementing NETs in specific circumstances are far from clear. For these reasons, negative emissions technologies are not an alternative to immediate massive emission reductions. Realistically, they could at best be efficient and effective as a supporting part of a larger package of measures. However, this would require their research and development to be accelerated and boosted so that the technologies reach maturity as quickly as possible.

Removing CO2 from the atmosphere on a permanent or long-term basis (for several decades at least) is key to achieving negative emissions. However, a trait shared by all natural sinks is that they are reversible and can quickly start to release their CO2. This must be taken into account in the regulatory design of measures with a view to ensuring a positive overall climate impact.

If the CO2 captured via BECCS or DACCS is then used, for example to manufacture synthetic fuels, the sinks created are only temporary. This does not count as negative emissions since the greenhouse gas is only removed from the atmosphere for a short time. That said, such an approach could help develop a climate-friendly circular economy.

What is Switzerland's position?

While the societal conversation referred to above is not yet taking place, there is a growing realisation that the Paris climate goals can no longer be met by emission reductions alone. This is demonstrated, for example, by a number of recent political initiatives. Postulate 18.4211, submitted by Adèle Thorens Goumaz and adopted by the National Council, poses the broad question of how important negative CO2 emissions might be for Switzerland's future climate policies. Postulate 19.3639, submitted by Jacques Bourgeois, focuses on the potential for carbon sequestration in Swiss soil. Similar initiatives are pending in a number of cantonal and city parliaments.

The Risk Dialogue Foundation conducted a stakeholder dialogue in 2018/19 at the request of the FOEN. Its report sets out the stakeholders' assessment of the opportunities, risks and costs of different NETs in Switzerland. The findings will inform the response to the two postulates mentioned above.

Given what we know about the dangers of unchecked climate change and the so far inadequate efforts to replace fossil fuels, Switzerland's long-term climate strategy will have to include NETs. Their primary purpose will be to offset 'unavoidable' emissions so that the overall net zero target for all greenhouse gases can be met by 2050.

Which emissions will be viewed as unavoidable will be a matter for public debate. The inclusion of negative emissions in the strategy does not guarantee that the required potential for such emissions exists in Switzerland. Further research and development will be needed to confirm and gradually expand this potential.

In contrast to NETs, Switzerland is not actively pursuing SRM approaches as part of its climate policy. However, it is playing an important international role with regard to this issue. This is because one of the most urgent tasks is to develop an ambitious international framework for regulating and monitoring research and development activities linked to large-scale interventions in the climate system (governance).

In March 2019, Switzerland and various other countries submitted a draft resolution to the fourth session of the United Nations Environment Assembly (the governing body of the UN Environment Programme (UNEP)), which would have been a first step in this direction. However, the motion failed to achieve a consensus and was rejected. The challenge of governance remains to be addressed.

Further information

Last modification 21.08.2019

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