Understanding land-based carbon dioxide removal in the context of the Rio Conventions
A framework for weighing land-based carbon removal against the three Rio Conventions
Read the published paper ↗doi.org/10.1016/j.oneear.2024.08.009
What 'nature-based' labels hide about removals
Carbon dioxide removal (CDR) is increasingly treated as essential to the Paris Agreement's climate goals. Current strategies lean primarily on land-based measures, such as afforestation, reforestation and soil carbon enhancement, which are commonly labelled 'nature-based solutions' or 'natural climate solutions'.
Many of these activities can in fact be detrimental to nature, particularly when they focus on carbon at the expense of biodiversity and other environmental objectives. The underlying measures range from restoring degraded ecosystems to establishing plantations in non-forested biomes. They differ sharply in their consequences for biodiversity and in the durability of the carbon they hold. Some forest definitions lack an ecological lens, counting any land with more than 10% tree cover as forest, and this contributes to forest expansion in non-forested biomes. We ask what constraints follow once land-based removal is evaluated against objectives the international community has already agreed, rather than against carbon accounting alone.
Ecosystem integrity within Rio Convention guardrails
We build a framework for evaluating trade-offs in land-based removal on the definition of nature-based solutions agreed at the fifth session of the UN Environment Assembly in 2022. That definition requires such solutions to deliver human well-being, ecosystem services, resilience and biodiversity benefits, while respecting social and environmental safeguards in line with the three Rio Conventions.
Those conventions, all established at the Rio Earth Summit in 1992, are the UN Framework Convention on Climate Change, the Convention on Biological Diversity and the Convention to Combat Desertification. Their objectives converge on ecosystem integrity, a concept spanning ecosystem condition, stability, processes, biodiversity and services. The framework has two parts. An ecosystem integrity lens separates removal activities into restoration, sustainable use and land-use change, the last being more likely to cause ecosystem degradation and to raise the risk of carbon loss. A set of guardrails draws on 77 instances of potential benefits and safeguards extracted from the three conventions, which we code into nine safeguard types across environmental, social and rights categories. We then apply the framework to recent quantified estimates of removal potential.
Cost and ecology both reduce the potential
Across global studies, we observe a cumulative removal potential of 57–1,052 GtCO2 from 2020 to 2100, which narrows to 57–385 GtCO2 once cost-effectiveness is considered. Allowing forests and other ecosystems to recover to their natural carbon carrying capacity has a large technical potential, estimated to peak at up to 8.5 GtCO2 per year. However, the literature does not consistently distinguish afforestation (planting where forests did not historically grow) from reforestation. Excluding estimates that are or could be afforestation caps reforestation at 5 GtCO2 per year, against 12 GtCO2 per year for afforestation. Cost-effective reforestation potentials are lower still, at 1.2–1.5 GtCO2 per year.
Government climate pledges for 2050 include removals of up to 5.0 GtCO2 per year, mostly conventional removal on land. Meeting these pledges is estimated to require an additional 990 million hectares of land, 479 million hectares of it for afforestation and reforestation. Safeguards interpreted in the context of the Rio Conventions are poorly represented in this literature: only one paper in our sample referenced human rights.
Prioritise co-benefits over sequestration
Viewing removal through an ecosystem integrity lens indicates that nature-based approaches should be implemented for their broader co-benefits, and not primarily for their carbon sequestration value. Attention to human rights and the rights of Indigenous peoples is a critical gap in these pathways. The literature assessing removal potentials largely ignores human rights, which the Rio Conventions increasingly recognise.
Several of the studies we review reiterate that conventional removal delivers mitigation benefits only when it is additional to, and not instead of, emission reductions. We argue that climate mitigation through land-based removal should not be pursued at the expense of biodiversity, ecosystem services or human well-being. Together, the Rio Conventions provide a guardrail for feasible and equitable implementation.
@article{dooley_understanding_2024,
title = {Understanding land-based carbon dioxide removal in the context of the {Rio} {Conventions}},
volume = {7},
copyright = {All rights reserved},
issn = {25903322},
url = {https://linkinghub.elsevier.com/retrieve/pii/S2590332224004196},
doi = {10.1016/j.oneear.2024.08.009},
abstract = {Carbon dioxide removal (CDR) is increasingly recognized as essential for achieving the Paris Agreement’s climate goals. Current CDR strategies primarily involve land-based measures, such as afforestation, reforestation, and soil carbon enhancement. These approaches, often labeled as nature-based solutions (NBS) or natural climate solutions (NCS), have sparked debate due to their potential adverse effects on biodiversity and uncertainty around the scale and durability of potential climate benefits. This paper introduces a framework for evaluating trade-offs in land-based CDR activities following the recent United Nations Environment Assembly definition of NBS. This framework emphasizes ecosystem integrity, human rights, and sustainable development, aligning with the objectives of the three Rio Conventions, which provide a guardrail to inform pathways toward feasible and equitable implementation. By applying this framework, we provide a more comprehensive understanding of the environmental and social constraints on CDR, ensuring that climate mitigation efforts do not compromise biodiversity, ecosystem services, or human well-being.},
language = {en},
number = {9},
urldate = {2024-09-23},
journal = {One Earth},
author = {Dooley, Kate and Pelz, Setu and Norton, Alexander},
month = sep,
year = {2024},
pages = {1501--1514},
}