5th July, 16:00 - 18:00 BST - Natural History Museum (NHM) Lecture Theatre
Oxford Net-Zero and the Environmental Change Institute, University of Oxford

Session summary

Session 3, NbS in Net-Zero: avoiding greenwashing & supporting sustainable development, outlined the real but limited potential of NbS for contributing to net-zero, and what ways countries and businesses should use policies, offsetting, and MRV. Stephanie Roe explained the science behind assessing the potential of NbS to contribute to climate mitigation, concluding that NbS can provide ~5-12 Gt CO2-eq/yr, which is approximately 10-24% of the total mitigation required by 2050 to keep warming within 1.5°C since preindustrial times. Over 80% of the mitigation potential of NbS arises in lower income nations, where feasibility barriers tend to be greatest. While this potential is significant and needed, NbS cannot mitigate climate change on its own and cannot compensate for delayed emissions reductions. To reduce the uncertainty of the estimates, there is a need for more science and improved models, particularly at the national level.

Aline Soterroni focused on her recent research on Brazil, where around three quarters of emissions come from land use and agriculture, including deforestation. Recent modelling results show that there is no credible pathway for the country to reach net-zero GHG emissions without NbS; in particular protection and restoration. She also found that the protection of ecosystems (including avoided deforestation) has the highest mitigation potential by far in Brazil. However, Aline highlighted how “Brazil’s latest nationally determined contribution is not ambitious. It has a net-zero GHG commitment, but it is not a robust plan.” In addition to scaling up the ambition in their NDC, Aline discussed how Brazil needs to fully enforce its national forest code policy as well as work directly with the private sector to ensure deforestation-free commodities.

Kaya Axelsson discussed guidelines and principles for assessing the net-zero strategies of governments and companies that include offsetting, as well as how to avoid greenwashing. Principles around responsible carbon offsetting include prioritising reducing one’s own emissions, including using insetting, while investing in offsets in parallel to account for residual, hard-to-abate emissions only. Kaya emphasised how organisations should increase the proportion of offsets in their portfolio which are carbon removals, shifting from often easier-to-measure reductions (avoided emissions). Offsets should also shift towards long-lived storage which includes NbS, noting that the permanence of carbon stored with NbS depends on strong governance, engaging local communities, long-term finance, ecosystem integrity for ecological resilience, and should also make use of legal mechanisms.

On the subject of MRV, Pete Smith, described an integrated framework for MRV, using the example of soil carbon, which combines methods such as long-term and short-term experiments, modelling, remote sensing data, and spatial soil resampling, among others, to improve accuracy. We have made significant progress in addressing the technical challenges around MRV for soil carbon, a notoriously hard thing to measure at scale, which in turn holds many lessons for MRV. Importantly, we need to not only think about MRV for carbon, but also for biodiversity, other markers of ecosystem health, and, crucially, local community benefits.

In the panel discussion, Sean Frisby noted the fundamental role of partnerships between governments and local implementers. Discussions centred on the challenges around ensuring a sufficiently high carbon price, including having a carbon price floor set by both governments and coalitions of businesses in the voluntary market.

Key take-homes

  • NbS have a real but limited potential to contribute to net-zero by 2050.
  • In Brazil, deforestation is the largest source of GHG emissions. Implementing the forest code would enable net-zero by 2050, but the private sector is needed.
  • Companies are cautious about setting net-zero targets & relying on offsets; insetting has potential, but remains ill-defined; and long-lived storage requires strong governance, long-term finance & local communities
  • Ensuring robust MRV is a key technical challenge for land-use based carbon removals.


  • Steve Smith 's photo
    Convenor & Chair

    Steve Smith

    Executive Director, Oxford Net Zero and CO2RE

    Steve's research interests lie at the intersection of climate science and policy. He has published on a range of topics including metrics for comparing emissions of different greenhouse gases, and the governance of carbon dioxide removal. He is co-developer of the Net Zero Tracker, a major global stocktake of net zero pledges. Steve is based at the Smith School of Enterprise and the Environment at the University of Oxford. There he directs two research programmes: Oxford Net Zero and CO2RE. He has a PhD in atmospheric physics from Imperial College London, and worked previously at the UK Climate Change Committee and in government.

  • Stephanie Roe's photo

    Stephanie Roe

    Global Climate Lead Scientist at WWF, Lead Author IPCC AR6 WGIII

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    How NbS can contribute to achieving net zero emissions

    Dr. Stephanie Roe is the Global Climate Lead Scientist at WWF, working to advance the science, leadership and progress on climate mitigation and adaptation, the climate and nature nexus, and nature-based solutions. She is also a Lead Author of the IPCC Sixth Assessment Report on Climate Change Mitigation, and serves on the SBTi Scientific Advisory Group. Her research focuses on biosphere-atmosphere dynamics, climate mitigation, the role of land and nature in climate pathways, and the response of terrestrial ecosystems to climate change.

  • Pete Smith's photo

    Pete Smith

    Professor of Soils and Global Change at the University of Aberdeen

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    Potential and limitations of land-based NbS for atmospheric greenhouse gas removal

    Pete Smith is Professor of Soils and Global Change at the Institute of Biological and Environmental Sciences at the University of Aberdeen (Scotland, UK) and Science Director of the Scottish Climate Change Centre of Expertise (ClimateXChange). His interests include climate change mitigation, soils, agriculture, food systems, ecosystem services and modelling.

  • Aline Soterroni 's photo

    Aline Soterroni

    Research Fellow at the Nature-based Solutions Initiative
    The role of NbS in Brazil’s net zero pathways

    Aline Soterroni is a Research Fellow at Oxford Net Zero and the Nature-based Solutions Initiative, where she investigates the socioeconomic and ecological outcomes of different pathways to net zero. Aline is interested in understanding the timeframes and spatial scales over which restoration, protection and sustainable management of working lands can enhance carbon stocks and reduce GHG emissions whilst supporting biodiversity, human adaptation to climate change and food security.

  • Kaya Axelsson's photo

    Kaya Axelsson

    Net Zero Policy Engagement Fellow at the University of Oxford

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    Avoiding greenwashing in carbon markets & The Oxford Offsetting Principles

    Kaya Axelsson is the Net Zero Policy Engagement Fellow at the University of Oxford. Kaya develops practical research on the socio-technical transition to net zero and engages widely with subnational stakeholders (companies and local governments) on their net zero strategies.

  • Sean Frisby's photo

    Sean Frisby

    Deputy Head – UK International Forests Unit, BEIS

    Sean is the Deputy Head – UK International Forests Unit, BEIS. He is also the UK government Deputy Director for the COP26 Presidency's World Leaders Summit: Action on Forests & Land Use event. Prior to this, he was the Head of BEIS Forests, Land Use & Carbon Markets Team

  • Cecile Girardin's photo

    Cecile Girardin

    Director-Nature Based Insetting | Technical Director-Nature Based Solutions Initiative

    Cecile combines years of experience in climate change policy analysis with a background in tropical ecology and thorough understanding of forest ecosystem functioning, providing a unique multidisciplinary approach to her work. As an environmental consultant, she developed strong skills in policy analysis and data manipulation. As researcher for ten years, she developed skills in data gathering and analysis through intensive fieldwork in tropical forests. She is an alumnus of Imperial College, Environmental Resources Management Ltd., the United Nation’s Food and Agriculture UN-REDD+ team, and the Oxford Martin School.