Negative emissions technologies

Group of people plant a tree together outdoors

The Foundation for Technology Assessment (TA-SWISS) has charged German technology research and consultancy institution Oeko-Institut and the Swiss Federal Laboratories for Materials Science and Technology (Empa) with conducting a study on the opportunities and risks associated with various technologies for permanently removing harmful greenhouse gases (GHG) from the atmosphere. In order for Switzerland to fulfil its international obligation to limit global warming to 1.5 degrees Celsius, human-related greenhouse gas emissions must be reduced to net zero. To achieve climate neutrality, Switzerland aims to significantly lower all greenhouse gas emissions caused by human activity by 2050 at the latest. The remaining, difficult to control GHG emissions will be actively removed from the atmosphere with the help of technology.

Although various technical solutions for carbon dioxide removal have been proposed, little is known about their effectiveness or their potential impact on Switzerland’s population and the environment. The central part of the interdisciplinary TA-SWISS study is a systematic survey of stakeholders and groups in Switzerland who are familiar with the technologies or their impacts; the survey aim is to pool existing knowledge and provide an overview of the various opinions on the opportunities and risks of negative emissions technologies (NET).

The study forms the basis for an early, fact-based evaluation of existing knowledge and of knowledge gaps with regard to NET. Despite current uncertainties surrounding technical aspects of NET, the study is designed to shed light on the potential of the new technologies and their possible consequences and side effects from various societal perspectives. Overall, the process encourages open and unbiased debate on the hopes and fears associated with NET. Ideally, these questions are considered at an early stage of technology development – before political and economic resolutions have been made on the actual use of these technological solutions – as such decisions cannot be easily revised at a later stage.

Study phases

The stakeholder survey is conducted using the LOTA software program; the goal is to gather as many different opinions as possible. LOTA is an innovative software-based methodology that represents the entire range of opinions a surveyed group holds on the opportunities and risks of a technology for both aggregated and globally recognised sustainable development goals. To use the online tool, registration is necessary; after registration, users will receive their access data by e-mail.

When completing the online survey with LOTA software, stakeholders are asked to describe the influencing factors and action modes they believe are relevant for achieving global climate goals. In the field of technology assessment, this methodology is a new, efficient way to survey a large group of stakeholders on their views with respect to the opportunities and risks of a technology, and it enables a graphical representation of where these views intersect (see figure). The graphical representation also serves as a basis for taking a closer look at potentially conflicting viewpoints and for examining related arguments and reasons for an opinion.

Over the course of the survey conducted using LOTA, stakeholders name initial influencing factors and make an assessment of the opportunities and risks of a NET in light of the following eight globally defined objectives:

  • Satisfaction of basic needs
  • Fundamental freedoms
  • Security and peace
  • Healthy environment
  • Rule of law
  • Equality
  • Standard of living
  • Global consensus and governance

The objectives were formulated on the basis of the United Nations Universal Declaration of Human Rights, UN Sustainable Development Goals, the Human Development Index and the Happy Planet Index; stakeholders are free to add to the list, as required.

After the stakeholder survey is completed, the participants’ assessments of the opportunities and risks of the individual NET are charted in the form of a map to represent the diversity of opinions. The findings are anonymised and published by TA-SWISS in the final project report.

Links and downloads


Project duration
October 2021 to March 2023

Project group

  • Dr Martin Cames, Oeko-Institut e.V. (project leader)
  • Dr Clemens Mader, Empa – Swiss Federal Laboratories for Materials Science and Technology

Supervisory group

  • Dr Stefan Vannoni, economist, CEO cemsuisse, president of the supervisory group, member of the TA-SWISS Steering Committee
  • Dr David Altwegg, economist and engineer, member of the TA-SWISS Steering Committee
  • Dr Andreas Bachmann, philosopher and ethicist, secretary of the Comité d'Ethique, Federal Office for the Environment
  • Professor Pascal Boivin, agronomist, HEPIA
  • Professor Alberto Bondolfi, University of Geneva, member of the TA-SWISS Steering Committee
  • Professor Jacques Dubochet, biophysicist, Nobel Prize laureate in chemistry, University of Lausanne, member of the TA-SWISS Steering Committee
  • Dr Samuel Eberenz, weather and climate risk expert, Stiftung Risiko-Dialog
  • Floris Heim, environmental impact assessment expert, Canton of Zurich, Amt für Abfall, Wasser, Energie und Luft
  • Dr Sonja Keel, environmental scientist, Agroscope
  • Dr Selma L'Orange Seigo, environmental psychologist and politician
  • Dr Urs Neu, meteorologist, deputy head of ProClim
  • Dr Otto Schäfer, biologist and ecotheologian
  • Dr Daniel Sutter, chemical scientist, Climeworks
  • Adèle Thorens, ethicist and politician, advisor and member of the Council of States
  • Dr Esther Thürig, scientist, team leader Forest Resources and Management, Swiss Federal Institute for Forest, Snow and Landscape Research
  • Dr Sophie Wenger Hintz, chemical scientist, NET climate policy, Federal Office for the Environment

Participating research organisations

Oeko-Institut – Institute for Applied Ecology in Germany – is an independent research and consultancy institution that works to achieve a sustainable future; the institute’s main clients are federal and state-level governmental ministries, public institutions, companies and the European Union. The team in the Energy and Climate Protection Division have acquired extensive experience with research on national and international climate policy. In addition to technical and economical areas of enquiry, analyses and recommendations also focus on questions concerning perceptions and acceptance of policies in society.

The institute’s Sustainable Products & Material Flows Division has broad expertise in sustainability and technology assessment. A wide-ranging set of methods forms the basis for expert opinions and studies, including life-cycle assessments and greenhouse gas inventories for processes, products and companies, life-cycle cost and eco-efficiency analyses, and potential substitution of hazardous substances as well as exposure scenarios. The Product Sustainability Assessment PROSA method developed at the institute provides strategic guidance in numerous projects.

Empa is an interdisciplinary research institution for materials science and technology that is part of the ETH Domain. Empa functions as a bridge between basic research and practical application. The researchers develop innovative solutions for major challenges facing industry and society – for example, in energy, construction and environmental technologies, and resource efficiency. Selecting the most efficient and direct technology transfer channels possible, Empa researchers and industrial partners work together to translate research findings into marketable innovations. Through this work, Empa makes a significant contribution to promoting the innovative and competitive vitality of Switzerland’s economy.

The Empa division ‘Technology and Society’ examines the function of new materials and technologies in the transition to a sustainable, post-fossil-fuel society; it also offers support in the development and design of sustainable materials, technologies and systems. The current research priorities at the division include the opportunities and risks of new materials, sustainable material life cycles, and the prospective assessment of new technologies from a life-cycle perspective.


Bénédicte Bonnet-Eymard, TA-SWISS

Öko-Institut: Dr. Martin Cames 

Empa: Dr. Clemens Mader