Climate technology pathways to net-zero emissions
02 December 2022

Solar geoengineering and negative emissions technologies hold great promise for addressing climate change. Three top climate scientists have embarked upon the largest-ever, multidisciplinary review of more than twenty emerging technologies. Their ERC-funded project GENIE aims to expand the toolkit for a zero-emissions future and warns about potential risks.

GENIE studies technological innovations that the engineering industry has put forward as options to complement mitigation and adaptation strategies to reverse climate change.

One such field are greenhouse gas removal (GGR) technologies, which take carbon dioxide gas from the atmosphere to store it in natural or geological sinks.

Also included in the study is solar radiation management (SRM), in which sunlight is reflected back in outer space to limit the increase of temperature, for instance through stratospheric aerosol injections or marine cloud brightening.

“Just a few years ago, these technologies were seen as weird and unrealistic”, says Benjamin Sovacool, who together with Jan Christoph Minx and Keywan Riahi leads the GENIE project.

“Now they are the cornerstone of any debate on climate change. They have the potential to grant our wishes but may also pose serious potential risks. It is imperative to understand better their inherent risks and benefits. We are talking about the fate of the planet; about what humanity should do in the next five years about a topic as devastating as climate change.”

No-persons land

GENIE is both highly multidisciplinary and comprehensive, consisting of six core work packages and two transversal work packages, twelve research questions and a team of 40 scientists and supporting staff working across 3 institutions.

More than twenty emerging climate tech innovations are being looked at in a holistic way: not just their feasibility is considered but also the socio-economic and political consequences of their large-scale deployment. The underlying idea is that technology is unlikely to achieve climate neutrality without accounting for possible social and political constraints.

“GENIE typifies what ERC Synergy Grants are supposed to do”, says Sovacool. “There is no other way that this project would have happened. We tried to get this funded before we approached the ERC. For some research councils, it was too much social science. For others, it was too technical. We were in this no-persons land between research councils because we draw on social science, evidence synthesis, modelling, media analysis, politics, justice, and ethics. It is probably the most deeply interdisciplinary project I have ever done.”


Mixing disciplines

For Sovacool, such projects thrive on the right match of personalities and on sound planning. “We often think of interdisciplinary as mixing disciplines or having challenges-based calls like in Horizon Europe or the Grant Challenges research fund, around which researchers coalesce in a way that avoids disciplinary silos. That is all true, but projects can still go bust if they have the wrong collaborators, if people do not get along.

Moreover, interdisciplinarity cannot be an after-thought. It cannot come at the end, in work package 7, in which you are finally going to think about cross-disciplinary issues. In GENIE, we have created a meta-theoretical approach: rather than basing our project in a single method or theory, we grounded our approach in different perspectives: on innovation and technology, on governance, and on ethics and justice.”

“There are some barriers that need to be worked out”, Sovacool continues. “Deconstructivist social sciences does not usually connect well with positivist quantitative work. Discourse analysis of power relations and white privilege does not really match with designing an integrative assessment model for climate change. The trick here is to make sure that the work programme has sufficient scope to work out these challenges.

We constantly exchange ideas and tackle things together as a team. We meet every other week online. There is no present agenda or predetermined findings; it is like an open discussion about disciplinary and methodological challenges, new studies, and so on. Every four months we meet in person, a week long, and we are rotating scholars to each other’s institution. Circulating people around creates respect, knowledge and discussion space.”

The climate talks at COP27 just ended. Was there enough consideration for the solar geoengineering and negative emissions technologies that you are studying?

They get too much attention in the IPCC’s climate scenarios and in modelling. These options appear so cheap in climate models, on paper at least. Their deployment potential is rapid and scalable, and they connect so well with other systems that the models go crazy. For instance direct air capture couples well with wind energy, hydro energy and nuclear power; there are projections that 50 to 80 percent of energy use in 2100 could go via direct air capture.

However, these are just models. We have been here before, with similar euphoria about other technologies that never took off, like fusion or hydrogen 20 years ago, or small modular reactors or methane hydrates or natural gas empowered cars. We know that there are these hype cycles.

Ironically, the policy architecture is just beginning to grasp things like carbon removal obligations or carbon border adjustments, and to think about how these options intersect with conventional policies such as carbon credits. The technology is ahead of the policy, which is perhaps normal. Then there is the media. In GENIE, we are doing a detailed work on media depictions of these technologies, mostly looking at Twitter. There you have a flourishing discussion. The media discourse is the most advanced, at least on social media.

Is it picking up in the US with the new policies on climate change of the Biden administration?

"Yes, it is picking up with both the new policies and venture capital. Major companies like Google and Meta are investing in a multi-billion dollar fund for carbon removal called Stripe. There are so many start-ups every month; I cannot keep track of them. In addition, the two dominant direct air capture companies, Carbon Engineering and Climeworks, are building large-scale prototype facilities in the US, on a megaton scale. The US is at the forefront of the deployment of some of these technologies, and I think that many people in Silicon Valley are as excited as people in federal policy."

What technology is the most promising?

"When we started in GENIE, we were asking many of these questions: is greenhouse gas removal better than solar radiation management? Which technologies have the most potential in terms of scalability? What about the total volumes of emission they can capture? What about their costs, and the window to be commercialised? We did an expert elicitation exercise. Over the course of four months, we contacted more than 70 experts with published patents on the technology or who are often cited in peer-reviewed articles. A first question was ‘do we have to depend on carbon dioxide removal to meet our climate targets?’ A strong majority said yes. Then we asked ‘do we need solar radiation management?’ Here we saw a split among experts.

Then we asked about the costs. High-tech options such as direct air capture and anti-weathering are expensive: unit carbon prices are above a hundred a ton. Forestation, soil management, and ecosystem restauration and other more common solutions are ten times cheaper. It was striking that many experts believed that some technologies such as ocean iron fertilization would never become mainstream, and others such as direct air capture only around 2047.

Amazingly, when you ask the true experts who are designing the technology and not the financers or venture capital, they are incredibly cautious. Most of the time, technology is too optimistic."

How do you explain that?

"I don’t know. Perhaps in 2022, scholars are more aware of hypes and are more cautious. There is also a notion to set expectations low and then exceed them, rather than set them high and fail to meet them. They could be practicing that."

In GENIE, you are integrating previously overlooked climate risks ranging from economic risks to vulnerability to political risk. Why is this important?

"There is still too much focus on the techno-economic dimensions: modelling, costs, performance, and deployment. There is very little discussion about indigenous communities, dispossession, justice, equity, job-creation, job-destruction, business models, and weapons.

Some of these technological options can be used to modify the weather and cause disasters. India could interfere with the monsoons in Pakistan, and vice versa. Alternatively, one could create a green OPEC where forestry countries span together. Brazil even proposed this at COP27.

We were in Australia earlier this year at the Great Barrier Reef, talking to aboriginal landowners about the marine protected areas, and how we could use cloud brightening and ecosystem restoration to protect native coral. Many support it, perhaps because they believe in the urgency of climate change, and they want to fight it. A better understanding of those technologies starts with the inclusion of indigenous communities, and learning about their concerns. What are the justice and equity issues of negative emissions and solar radiation management? What particular groups will be most vulnerable to their deployment?

Just to give you a sense: if we do widespread afforestation or widespread bioenergy with carbon capture in storage, we will occupy more land than we currently grow crops on. So imagine all current land issues around indigenous peoples: we would double the number of problems if we have to use land for carbon renewable. If we are not careful with how we guide the deployment of these big scale technologies, this could result in new patterns of colonialism. These new, non-technical concerns will become the most important in the next ten years, more so than the technical aspects."


Benjamin K. Sovacool is Distinguished Professor of Business and Social Sciences at Aarhus University, and Professor of Energy Policy at the University of Sussex. He was formerly Director of the Danish Center for Energy Technology at Aarhus University. He was a Lead Author of the Intergovernmental Panel on Climate Change’s Sixth Assessment Report (AR6), published in 2022, and an Advisor on Energy to the European Commission’s Directorate General for Research and Innovation.

Jan Christoph Minx is head of the working group Applied Sustainability Science at the Mercator Research Institute in Berlin. He is also a Visiting Professor for Climate Change and Public Policy at the Priestley International Centre for Climate at the University of Leeds.

Keywan Riahi is the Director of the Energy, Climate and Environment Program at the International Institute for Applied Systems Analysis. He also is a visiting professor of Energy Systems Analysis at the Graz University of Technology and a fellow at the Payne Institute of the Colorado School of Mines. In 2021, he joined the 10-Member Group to advise the UN on the Technology Facilitation Mechanism for the implementation of the Agenda 2030.

Project information

GENIE: Sociotechnical pathways for a zero-emissions future
Benjamin Sovacool
Host institution:
Aarhus university
Jan Christoph Minx
Host institution:
Mercator Research Institute on Global Commons and Climate Change (MCC)
Keywan Riahi
Host institution:
International Institute for Applied Systems Analysis (IIASA)
Call details
ERC funding
9 187 902 €