Limiting Carbon

Dioxide Removal

Could Exacerbate

Global Economic

Inequality

Discussion Paper

Raphael Apeaning, Puneet Kamboj,

and Mohamad Hejazi

April 2025 I Doi: 10.30573/KS--2025-DP07

About KAPSARC

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economics and sustainability providing advisory services to

entities and authorities in the Saudi energy sector to advance

Saudi Arabia’s energy sector and inform global policies through

evidence-based advice and applied research.

This publication is also available in Arabic.

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3Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Abstract

The Paris Agreement’s goal of limiting global warming to well below

2 degrees Celsius (°C), and ideally 1.5°C, above pre-industrial levels, places

signiﬁcant emphasis on carbon dioxide removal (CDR) technologies. However,

the global landscape for CDR deployment remains uneven, with signiﬁcant

disparities in technological capacity, economic readiness, and regional

ambition. This study investigates how limited access to CDR technologies

could exacerbate global economic inequality under a 1.5°C pathway. Using

the Global Change Analysis Model (GCAM v6.0), six scenarios – ranging from

unrestricted CDR availability to constrained deployment – are evaluated. Our

ﬁndings reveal that constrained CDR availability signiﬁcantly increases median

global carbon prices, rising from US$588 per ton of carbon dioxide (tCO2) in

the full CDR portfolio scenario to $937/tCO2 by 2055 in the most restrictive

scenario. By 2100, some regions will face prices exceeding $3,000/tCO2,

underscoring stark regional inequalities. These elevated carbon prices could

deepen economic disparities, particularly in developing nations and fossil fuel-

dependent economies. Furthermore, constrained CDR availability could also

amplify inequalities in energy and food security, disproportionately aecting

poorer regions. The study underscores the need for equitable CDR access

to support a just global transition to a low-carbon future, oering valuable

insights for policymakers designing more equitable climate strategies.

Keywords: Carbon Dioxide Removal, Economic Inequality, Equitable Climate Policy

4Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

1. Introduction

The Paris Agreement’s goal of limiting global warming to well below

2 degrees Celsius (°C), and ideally 1.5°C, above pre-industrial levels has

elevated carbon dioxide removal (CDR) technologies to a critical role in

climate mitigation action (Fuss 2014; Smith et al. 2016). Despite criticisms

centered on the immaturity of CDR and concerns that it might divert attention

from immediate emission reduction eorts, there is growing consensus

that large-scale deployment will be essential in meeting the Paris targets

(Ganti et al. 2024; Lamb et al. 2024; Andreoni, Emmerling, and Tavoni 2023;

McLaren 2020). The increasing focus on CDR is also driven by the fact that

many scenarios aligned with the Paris Agreement rely on multi-gigaton-

scale CDR deployment to stabilize the climate within safe limits (Tamme and

Beck 2021; Powis et al. 2023). As global emissions continue to rise, CDRs

are recognized as crucial for osetting residual emissions, particularly from

hard-to-abate sectors, and for addressing potential temperature overshoots

(Iyer et al. 2018; Creutzig et al. 2019; Smith, Vaughan, and Forster 2024).

Consequently, CDR has transitioned from a theoretical concept to an

indispensable element of national and regional decarbonization strategies,

essential for achieving signiﬁcant emission reductions (McMullin et al. 2020).

However, the global landscape for CDR deployment

remains uneven, with signiﬁcant disparities in

technological capacity, economic readiness, and regional

ambition (Minx et al. 2018; Powis et al. 2023). These

variations are evident in the long-term low-emission

development strategies (LT-LEDS) submitted by various

nations, where pathways for CDR implementation dier

markedly (Smith, Vaughan, and Forster 2024; McMullin

et al. 2020; Lamb et al. 2024; Buylova et al. 2021).

This divergence represents the uncertainties about

the economic feasibility, scalability, and biophysical

constraints of dierent CDR technologies across regions

(Geden and Schenuit 2020).

There are many challenges to scaling CDR technologies,

particularly in less wealthy regions (Bednar, Obersteiner,

and Wagner 2019). High upfront investments in

technologies like direct air capture (DAC) and bioenergy

with carbon capture and storage (BECCS) create

ﬁnancial barriers, especially in regions without advanced

technological infrastructure or access to robust ﬁnancial

systems (Nemet et al. 2018; Bednar, Obersteiner, and

Wagner 2019). Moreover, the eectiveness of CDR

technologies hinges on the availability of supporting

infrastructure, such as carbon capture and storage (CCS),

which is costly to develop and unevenly distributed

globally (Galán-Martín et al. 2021; Kazlou, Cherp, and

Jewell 2024). Beyond economic constraints, biophysical

limitations – such as land and water availability – also

pose signiﬁcant challenges to the scalability of many

CDR technologies (Smith et al. 2016; Fuhrman et al. 2020,

2023). These limitations may exacerbate tensions around

the use of land for carbon removal rather than other

critical needs, such as food production, particularly in

developing regions (Fuhrman et al. 2020, 2023; Deprez

et al. 2024).

5Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

As countries intensify their eorts to meet the Paris

Agreement’s 1.5°C target through enhanced emission

reductions and large-scale CDR initiatives, concerns

about economic inequality have grown (Iyer et al.

2018; Pozo et al. 2022; Andreoni, Emmerling, and

Tavoni 2023). These concerns stem from pronounced

disparities in regional capacities to deploy CDR

technologies, raising critical policy issues around

equity and justice in global climate mitigation eorts

(Sovacool, Baum, and Low 2023; Fyson et al. 2020).

Addressing these risks and challenges is imperative

to ensure progress toward climate goals is equitable.

In this context, our study examines the implications of

limited CDR deployment on global economic inequality,

ﬁlling a critical gap in the literature. Using the Global

Change Analysis Model (GCAM version 6.0), we explore

six distinct scenarios reﬂecting varying degrees of

CDR limitations – from unconstrained technological

availability to restrictions on CDR portfolios and

enabling resources (see Table 1 in Section 2 for detailed

explanations). The CDR technology scenarios are

modeled under region-speciﬁc climate action pathways

targeting the Paris Agreement’s 1.5°C goal. By analyzing

CDR deployment across varying ambition levels and

resource constraints, we assess how unequal access to

CDR – driven by key limiting factors – can exacerbate

regional economic disparities. Our ﬁndings underscore

that without a comprehensive suite of CDR options and

supportive policies, achieving regional decarbonization

targets could become prohibitively expensive,

jeopardizing the feasibility of meeting long-term climate

goals. Moreover, limitations on CDR can exacerbate

energy and food security inequality, disproportionately

impacting poorer regions. This highlights the critical

role of CDR in complementing traditional mitigation

strategies to address existing gaps and ensure a more

equitable transition to a low-carbon future. Overall,

these insights are critical for designing more equitable

and inclusive global climate strategies and contribute

to ongoing policy dialogues on achieving climate goals

without increasing regional inequalities (Fyson et al.

2020; Lee, Fyson, and Schleussner 2021; Carton, Lund,

and Dooley 2021).

The study is structured as follows: The Methodology

section outlines the scenarios and model used, the

Results section presents key ﬁndings, and the Discussion

and Conclusion section outlines their implications.

6Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

2. Methodology

2.1 GCAM Overview

We applied the Global Change Analysis Model (GCAM version 6.0) to

evaluate six CDR scenarios under regionalized decarbonization pathways.

The pathways aim to limit the average global temperature to 1.5°C above pre-

industrial levels by 2100. GCAM is an open-source, integrated assessment

model that captures the complex interactions across global systems including

energy, economy, land use, water, and climate (Calvin et al. 2019). It covers

32 geopolitical regions, with detailed representations of energy, agriculture,

land allocation, and water use across 384 land subregions and 235 water

basins. GCAM operates in ﬁve-year time steps from 2015 to 2100, dynamically

solving for equilibrium prices and quantities across energy, agriculture, land,

and water markets, while also tracking the emissions of 24 greenhouse

gases, short-lived climate pollutants, and ozone precursors. As a dynamic

recursive model, GCAM bases the decisions in each period on current market

conditions, without perfect foresight of future changes. Model outcomes are

driven by exogenous assumptions of population growth, labor productivity,

resources, technologies, and climate policies speciﬁc to each region. Under

climate-constrained scenarios, GCAM’s economic agents choose between

mitigation strategies, such as fuel switching, energy eciency improvements,

carbon capture, and CDR technologies, to meet regional or global

emission targets.

In our study, we evaluate regional carbon pricing and

the associated policy costs across various GCAM

scenarios. GCAM estimates welfare losses from

climate policies through a deadweight loss approach.

It does so by calibrating marginal abatement costs

based on endogenous carbon prices and the resulting

greenhouse gas (GHG) emission reductions driven

by technological and socio-economic factors (Peng

et al. 2021). The marginal abatement cost curve

is divided into ﬁve carbon price intervals for each

period (i.e., 0%-20%, 20%-40%, 40%-60%, 60%-80%,

and 80%-100%). Deadweight losses are assessed

by comparing emissions under carbon pricing to a

baseline without such a policy. Mitigation costs are

determined by calculating the area under the marginal

abatement curve; eectively integrating carbon prices

over the range of emission reductions inﬂuenced by

the policy.

7Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

2.2 Carbon Capture

and Storage

and Bioenergy

Resources in GCAM

Carbon capture and storage (CCS) is modeled extensively

in GCAM across multiple sectors, including electricity

generation, reﬁning, industry, and hydrogen production

(Muratori et al. 2017). Technologies such as pulverized

coal with CCS, natural gas combined cycle with CCS, and

integrated gasiﬁcation combined cycle with CCS compete

with other technologies based on their levelized costs.

The latter include capital, operation, maintenance, fuel,

and emission costs. The availability of CCS is modeled

regionally, reﬂecting local resource availability, storage

capacity, and economic conditions. The model also

accounts for the transportation and storage of CO2,

incorporating regional variations in storage costs

and infrastructure needs. CCS plays a critical role in

decarbonizing fossil fuel-based energy systems, as

well as in BECCS and DAC systems (see Figure S2 for a

comparison of this study’s CCS output with the AR6 1.5°C

scenarios).

In GCAM, bioenergy resources are represented as part

of the integrated energy and agriculture-land system,

where bioenergy crops compete with food crops, forests,

pasture, and other land uses. Land use is allocated based

on its expected proﬁtability, factoring in crop yields,

market prices and production costs. GCAM models

bioenergy conversion from various sources, including

dedicated bioenergy crops, agricultural residues, and

forestry by-products. Bioenergy is primarily used for

electricity generation, reﬁning, and hydrogen production.

It can also be coupled with CCS to form BECCS, which

generates negative emissions by sequestering CO2.

It is essential to emphasize that GCAM incorporates

externality constraints on land use to mitigate

unsustainable bioenergy deployment. These constraints

help align bioenergy production with environmental

and sustainability goals. This ensures that bioenergy

expansion is balanced with other land-use priorities,

supporting more sustainable development pathways.

GCAM’s bioenergy system is tightly linked to the

agricultural sector. The production of bioenergy aects

land allocation, food prices, and agricultural trade, with

potential consequences for food security and ecosystem

services. The competition between bioenergy and other

agricultural uses of land is inﬂuenced by policy incentives,

regional land use regulations, and market conditions,

making bioenergy a key component of GCAM’s energy

and agricultural systems.

2.3 CDR Technology

Portfolio in GCAM

This study examines ﬁve key CDR technologies –

namely, aorestation/reforestation (AF/RF), BECCS,

DAC, enhanced weathering (EW), and biochar. In GCAM,

these technologies are uniquely represented. The

category of AF/RF includes both the establishment of

forests on lands that were not previously forested and

the replanting of forests on deforested lands. This dual

approach is incentivized through policies that assign a

value to land use CO2 emissions, eectively integrating

the forest-based carbon sequestration beneﬁts into an

economic framework (Zhao et al. 2024). Within GCAM,

aorestation competes with other land uses, such as

agriculture and bioenergy production (Calvin et al.

2019). This competition is inﬂuenced by carbon pricing

mechanisms, which aect the relative proﬁtability of

dierent land uses. BECCS integrates across multiple

sectors, including reﬁning, electricity, and hydrogen

production, combining bioenergy with carbon

capture and storage to achieve negative emissions

by sequestering CO2 from biomass combustion (see

tables S3 and S4 for the cost assumptions of BECCS

technologies) (Muratori et al. 2017; Zhao et al. 2024). DAC

is modeled with three archetypes – high temperature

(natural gas-based), electric heat-driven, and low

temperature (using heat pumps) – to capture CO2

directly from the atmosphere. Regional deployment

is inﬂuenced by technology costs, energy inputs, and

storage capacity (Fuhrman et al. 2020, 2023). EW is

modeled based on the energy required for rock grinding

and transport, with regional cost curves reﬂecting the

available resources and infrastructure (Fuhrman et al.

2023). Lastly, biochar, produced via the slow pyrolysis

of biomass, enhances the capacity for carbon storage

in soil (Fuhrman et al. 2023; Bergero et al. 2024).

The model captures the competition between using

biomass for biochar versus other energy production

methods, such as BECCS. It also considers biochar’s

carbon sequestration potential over centuries, along

with additional beneﬁts like improved crop yields,

which depend on local irrigation and climate conditions

(Bergero et al. 2024). In GCAM, the deployment of these

8Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

CDR technologies is driven by economic factors, policy

incentives, and technological advancements, alongside

other mitigation strategies such as renewable energy

adoption and energy eciency improvements (see

tables S3-S7 for details about the CDR parameters). The

model captures the trade-os between CDR and other

emission reduction options, oering a comprehensive

view of how dierent regions can achieve their

climate targets.

2.4 Measuring

Inequality

This analysis employs the mean log deviation (MLD)

metric, a measure of income inequality rooted in

information theory, to quantify distribution disparities.

The MLD is particularly suitable for decomposing total

inequality into its constituent components, allowing

for a detailed examination of the sources of inequality.

Unlike other measures, such as the Gini coecient,

the MLD is sensitive to changes across the entire

distribution (Cowell and Flachaire 2023). This makes it

ideal for evaluating disparities in policy costs or income

levels where both within-region and between-region

dierences matter.

As part of the generalized entropy (GE) class of

indices, the MLD is derived from information theory

and captures relative disparities by measuring the

“distance” of individual or subgroup values from their

respective means. Its additive decomposability enables

a clear separation of total inequality into inter-regional

and intra-regional components, providing insights into

whether disparities arise from local dierences within

regions or broader structural imbalances between

regions. In other words, the inter-regional component

quantiﬁes inequality between regions by comparing

the mean value of each region to the global mean.

The intra-regional component quantiﬁes inequality

within regions by averaging the deviations of individual

values within a region from that region’s mean. This

decomposition enables policymakers and researchers

to isolate the drivers of inequality into both regional and

global disparities eectively. It also provides a robust

framework for evaluating the inequality implications

of climate policy scenarios. Equations 1, 2 and 3 show

the total and subcomponents of MLD expressed

mathematically as:

𝑀𝐿𝐷𝑡𝑜𝑡𝑎𝑙 = 𝑀𝐿𝐷𝑖𝑛𝑡𝑒𝑟 + 𝑀𝐿𝐷𝑖𝑛𝑡𝑟𝑎 Equation (1)

Where:

MLDinter: Quantiﬁes inequality between regions by

comparing each region’s mean per capita value to the

global mean.

MLDintra: Quantiﬁes inequality within regions by averaging

the disparities of individuals or subgroups relative to their

region’s mean.

Equation (2)

MLDintra

∑

Nri

∑

⎛

⎝

⎜⎞

⎠

⎟

Equation (3)

Where :

• R: Total number of regions.

•

y

: Global mean per capita policy cost.

•

yr

: Mean per capita policy cost in region r.

• yi,r: Per capita policy cost for individual i in region r.

• Nr: Number of individuals in region r.

2.5 Scenario Design

The study examines various scenarios to assess the

impact of CDR technology limitations on emissions

reduction strategies. The FullTech scenario serves

as a benchmark, oering maximum ﬂexibility with no

restrictions on CDR. In contrast, the CCS50 scenario

restricts CCS deployment to 50% capacity, evaluating

how relying on engineering CDR technologies like CCS

may impact the achievement of emission goals.

Although the 50% limitation may appear arbitrary, it

is intended to reﬂect real-world constraints such as

technological readiness, economic feasibility, and

societal acceptance, which can impede full-scale CCS

implementation. The Bio100 scenario limits global

bioenergy usage to 100 exajoules (EJ) per year and

explores how this constraint aects the capacity for

negative emissions from BECCS and biochar. The

100 EJ limit on bioenergy reﬂects assessments of

sustainable biomass availability, considering biophysical

constraints such as land and water resources. The limit

is aimed at balancing climate mitigation eorts with

ecological and socio-economic considerations like

food security and biodiversity conservation (Creutzig

et al. 2014). The LimCDR scenario excludes novel

9Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Table 1. Scenario description.

Scenario Description Key CDR limitations Objective/insight

FullTech No limitations on CDR or CCS

technologies, providing maximum

ﬂexibility for emissions reduction. All

technologies are available.

None. Benchmark for maximum

potential of negative

emissions.

CCS50 Similar to FullTech but with CCS

deployment restricted to 50%

capacity, exploring the eect of

limited CCS availability.

CCS capacity limited

to 50%.

Assess reliance on CCS

for emissions goals.

Bio100 Mirrors FullTech but limits bioenergy

to 100 EJ, evaluating how restricted

bioenergy impacts negative

emissions capacity.

Bioenergy limited to

100 EJ/yr.

Impact of limited

bioenergy on BECCS

and biochar.

LimCDR Limits the CDR portfolio by excluding

newer technologies like enhanced

weathering (EW) and direct air

capture (DAC).

No EW or DAC. Eects of a restricted

CDR portfolio.

LimCDR+CCS50 Combines a limited CDR portfolio

(no EW or DAC) with CCS capacity

restricted to 50%.

Limited CDR

options; CCS

at 50%.

Impact of limited CDR

and reduced CCS on

emissions goals.

LimCDR+Bio100 Limits both CDR technologies (no EW

and DAC) and bioenergy capacity

to 100 EJ, assessing combined

technology and resource constraints

Limited CDR

options; bioenergy

at 100 EJ/yr.

Dual impact of resource

and technology

constraints.

Note: yr = year.

CDR technologies such as EW and DAC to assess the

eects of a restricted CDR portfolio. This exclusion is

based on the relatively high costs, energy intensity,

and current technological immaturity of EW and DAC

compared to more established options like BECCS

and biochar. Further, the LimCDR+CCS50 scenario

combines the limitations of LimCDR with a 50%

2.6 Climate Pathway

and Socio-Economic

Assumptions

This study’s regional emissions constraint design builds

upon methodologies from Iyer et al. (2022), integrating

the latest nationally determined contributions (NDCs),

restriction on CCS capacity, analyzing the compounded

impact on emissions reduction objectives. Lastly,

the LimCDR+Bio100 scenario imposes a limited CDR

portfolio (excluding EW and DAC) and a bioenergy

cap of 100 EJ per year to evaluate the dual impact

of resource and technology constraints on achieving

emissions targets.

long-term strategies (LTS), net-zero pledges, and post-

2030 decarbonization trajectories. All scenarios are

modeled under the Shared Socioeconomic Pathway 2

(SSP2), which represents a “middle-of-the-road” scenario

where social, economic, and technological trends follow

historical patterns (Fricko et al. 2017).

In the near term, the study assumes countries will

implement their NDCs, aligning regional emissions

with the current climate commitments. Using the NDCs

10Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

allows us reﬂect the varying levels of commitment

and capability across regions, acknowledging diverse

starting points and climate ambitions globally. Long-

term emissions trajectories incorporate LTS and

net-zero pledges. Countries with explicit long-term

strategies or net-zero commitments follow linear

reductions to their target years, typically 2050, after

which emissions stabilize. For countries without deﬁned

long-term strategies, a post-2030 decarbonization rate

of 5% is applied, representing a moderately ambitious

level of emissions reduction (see Table S1 for more

details about post-2030 decarbonization assumptions).

This ensures that regions without formal long-term

pathways still contribute meaningfully to global

mitigation eorts, balancing realistic projections with

uncertainties around future commitments (Grant 2022;

Baptista et al. 2022). Following Ou et al. (2021) and

Iyer et al. (2022), the decarbonization rate is calculated

based on the carbon intensity of gross domestic

product (GDP).

The regionalized emission constraints framework

enables the exploration of global 1.5°C pathways under

varying assumptions and ambition levels, oering

insights into how regions can achieve their climate

targets. By simulating a “second-best world” without

emissions trading, the modeling exercise highlights the

challenges regions might face due to diering economic

and technological capacities (Bauer et al. 2020). This

approach provides a realistic view of the complexities of

achieving global climate goals under stricter regulations

and limited international cooperation. Overall, the design

of the technology and emissions reduction scenarios

highlights the necessity for tailored, region-speciﬁc

strategies. This is because regions must depend on

their own resources and capacities to implement CDR

technologies and achieve decarbonization targets.

This approach highlights the signiﬁcance of customized

climate action plans, providing a nuanced perspective on

how varying regional capabilities inﬂuence global climate

outcomes (Rogelj et al. 2019).

11Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

3. Results

3.1 Emission and Carbon Dioxide Removal

Technology Proﬁles

Figure 1a illustrates the emission proﬁles for the regionalized decarbonization

scenarios aimed at meeting the Paris Agreement’s 1.5°C target (see the

Methodology section for details). The results demonstrate the pivotal role

of CDR technologies in achieving this ambitious climate goal. Global net

greenhouse gas emissions peak around 2030 and then rapidly decline,

reaching net zero by 2055. During this period, CDR deployment scales up

substantially, rising from 1.31 gigatons of CO2 (GtCO2) to 1.67 GtCO2 per year

(GtCO2/yr) in 2030 to 8.5 GtCO2 to 10.7 GtCO2/yr by 2055. The scale-up of

CDR highlights the increasing reliance on it in regional mitigation strategies.

Beyond the net-zero year, residual emissions stabilize between 10.5 GtCO2

and 21.9 GtCO2/yr, depending on the scenario (Figure 1b). Continued

CDR deployment beyond net zero is essential for achieving net-negative

emissions, which is crucial for keeping the global temperature rise under the

1.5°C threshold (Johansson et al. 2020; DeAngelo et al. 2021).

In the FullTech scenario, which assumes unrestricted

access to CDR technologies, gross CDR deployment

rises from 11.5 GtCO2/yr in 2055 to 17.8 GtCO2/yr by 2100

(Figure 1b). In contrast, scenarios with restricted CDR

show more moderate growth, starting at lower levels of

8.5-10.6 GtCO2/yr by 2055. Among the engineering CDR

solutions, BECCS is the largest contributor, accounting

for 42.4%-63.9% of gross CDR in 2055, followed by

DAC (5.3%-11.9%), biochar (4.1%-6.3%), and EW (4.2%-

6.3%). Land-use-based CDR, primarily aorestation,

plays a signiﬁcant role in achieving net-zero emissions,

contributing 27.7%-47.3% of gross CDR, with a greater

contribution in scenarios where DAC and EW are

unavailable. Regional CDR deployment varies widely.

By 2055, the United States (U.S.) (17.8%), China (11.78%),

and the EU-15 (8.3%) lead in the FullTech scenario (see

Figure S2). By 2100, the distribution shifts, with China

(15.13%), the U.S. (12.83%), and the Middle East (6.74%)

emerging as major contributors, reﬂecting evolving

regional capacities and demand for CDR technologies.

12Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure 1. 1.5°C emissions and CDR proﬁles.

Source: Authors.

Note: LUC = Land use change ; Other Energy Trans. = Other energy transformation

a. Sectoral emissions trajectories from 2020 to 2100 across six scenarios, showing contributions from industry, transportation, electricity, and carbon

removal technologies (e.g., BECCS, DAC, aorestation). The dashed vertical line marks the net-zero year (2055), while the purple and black solid lines

represent global net CO₂ and GHG emissions, respectively.

b. Total residual emissions (left) and gross CDR deployment (right) from 2020 to 2100. The dashed vertical line indicates the net-zero year (2055).

13Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

3.2 Sectoral

Implications of

Limited CDR

Availability

Limited availability of CDR technologies profoundly

inﬂuences mitigation strategies across sectors. Compared

to the FullTech scenario (see Figure 2b), scenarios with

CDR constraints exhibit signiﬁcant shifts in deployment

patterns. BECCS deployment is notably reduced – by

35.3% to 37.3% relative to FullTech – while biochar

utilization increases by 5.7% to 22% in the net-zero year.

Aorestation also rises sharply in scenarios where DAC

and EW are unavailable, compensating for the limited

CDR portfolio. Moreover, when all CDR technologies

are available, constraints on CCS and bioenergy further

hinder the deployment of BECCS, DAC, and EW, thereby

reducing their overall contributions to carbon removal.

The availability – or limitation – of CDR has a substantial

impact on sectoral emissions, particularly in hard-to-

abate sectors such as industry and transportation.

Under restricted CDR availability, the industrial sector

must reduce its emissions by an additional 2% to

11.5% by 2055 compared to the FullTech scenario; this

increases to 52.5% to 69.2% by 2100 (Figure 2a). The

transportation sector, which heavily relies on CDR due to

limited decarbonization alternatives, faces even steeper

reductions – ranging from 5.1% to 24.2% by 2055, and

66.5% to 86.1% by 2100.

Additionally, energy transformation sectors, such

as electricity generation, experience signiﬁcant

constraints on their decarbonization potential

under limited CDR availability. The stiﬂing of BECCS

deployment aects the cost-eectiveness of

decarbonizing electricity, reﬁned liquids, and hydrogen

production. These ﬁndings underscore the critical

trade-os in CDR technology deployment, illustrating

how technological limitations shape the pathways to

achieving climate targets.

14Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure 2. Impact of constrained CDR on residual emissions and CDR contributions.

Source: Authors.

Note: LUC = land use change; Other energy trans. = other energy transformation

a. Percentage deviations in sectoral emission reductions due to constrained CDR availability, compared to the FullTech scenario, shown for the net-

zero year (2055) and 2100.

b. Contributions of CDR technologies in limited CDR scenarios compared to FullTech for 2055 and 2100. Gray cells indicate scenarios where speciﬁc

CDR technologies are unavailable.

3.3 Carbon Price

Implications

The limited availability of CDR technologies signiﬁcantly

hinders emission reductions in sectors with limited

decarbonization options. Consequently, these hard-to-

abate sectors are compelled to rely on less cost-eective

mitigation strategies to oset their residual emissions

(Riahi et al. 2021; De Cian et al. 2016; Grant et al. 2021).

Our modeling results in Figure 3 demonstrate that

constraints on CDR technologies lead to an elevated

shadow price of carbon, resulting in the increased

heterogeneity of carbon prices across regions as they

strive to meet ambitious climate goals under technological

15Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

limitations. This variation in carbon prices highlights

the diering regional impacts of and responses to CDR

limitations, with some areas facing signiﬁcantly higher

economic burdens.

Figure 3a reveals that the median regional carbon

price falls between $50 and $104 per tonne of CO2

(tCO2) in 2025. By 2055, as emission reduction

commitments intensify, these prices rise sharply, with

signiﬁcant variation across scenarios. In scenarios with

restricted CDR deployment – such as LimCDR, CCS50,

LimCDR+CCS50, Bio100, and LimCDR+Bio100 – the

median carbon price increases to $679, $817, $821, $848,

and $937 tCO2, respectively. By comparison, the FullTech

scenario, which assumes unrestricted CDR access,

maintains a lower median carbon price of $588/tCO2. By

2100, carbon prices in the constrained CDR scenarios

escalate further, ranging from $1,318 to $2,190/tCO2, while

FullTech remains the most cost-eective, with a carbon

price of $628/tCO2.

Additionally, the spread of regional carbon prices,

represented by interquartile ranges (IQRs), expands

considerably in scenarios with limited CDR availability.

By the net-zero year, the IQR for the carbon price in

constrained scenarios ranges from $198 to $298/tCO2,

reﬂecting signiﬁcant regional price variation. In contrast,

the FullTech scenario shows a narrower IQR of $142/

tCO2, indicating more uniform pricing across regions

due to the broader availability of mitigation options. By

2100, this disparity becomes even more pronounced,

with scenarios such as Bio100 and LimCDR+Bio100

reaching IQRs of $479 and $643/tCO2, respectively,

while FullTech remains relatively stable with an IQR of

$193/tCO2.

These disparities in carbon prices highlight substantial

regional inequalities, carrying signiﬁcant implications

for global economic inequality, especially in developing

regions. As shown in Figure 3b, regions such as Africa

and parts of Asia face disproportionately higher carbon

prices under constrained scenarios like LimCDR,

LimCDR+CCS50, and LimCDR+Bio100. For instance,

under the LimCDR+Bio100 scenario, Eastern Africa faces

carbon prices as high as $3,059/tCO2 by 2100, while

South Asia reaches $2,909/tCO2. In contrast, developed

regions, such as the U.S., experience lower carbon prices,

peaking at $1,871/tCO2 under the same scenario.

These exceptionally high carbon prices not only

underscore regional inequalities but also raise critical

questions about the practical feasibility of achieving

region-speciﬁc emission goals with limited CDR

availability. Prices in excess of $3,000/tCO2 represent

a signiﬁcant economic burden that many developing

regions are unlikely to sustain, potentially rendering these

mitigation pathways unachievable without substantial

international support. It is crucial that climate policies are

economically feasible, particularly in regions with limited

ﬁscal capacity, and that policy frameworks align ambitious

mitigation goals with economic realities.

The stark dierences in regional carbon prices between

constrained and unrestricted CDR scenarios highlight

the essential role of a comprehensive CDR technology

portfolio in mitigating feasibility challenges (see Table S2

for more details about the regional carbon prices).

Investing in equitable access to CDR technologies

could help lower global carbon prices, making

ambitious climate targets more economically viable

for developing regions.

16Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure 3. Projected carbon prices and their regional distribution (2020-2100).

Source: Authors.

a. Projected global carbon prices from 2020 to 2100. Solid lines represent the median carbon price for each scenario, i.e., the central estimate of the

regional carbon price distribution. The shaded areas denote the interquartile range (IQR), capturing the middle 50% of values between the 25th and

75th percentiles. This provides a measure of regional price variability within each scenario.

b. Regional carbon prices for 2055 (top) and 2100 (bottom). Separate carbon price scales are used for each year to emphasize interregional

dierences. The scales for 2055 and 2100 should be interpreted independently.

17Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

3.4 Global and

Contextual

Implications of

Economic Inequality

The dynamics and disparities in carbon pricing outcomes

become particularly evident when assessed through the

lens of the per capita policy cost of emissions mitigation

(Fremstad and Paul 2019). Globally, per capita policy

cost inequality is shaped by a combination of regional

policies, economic structures, and diering mitigation and

CDR deployment strategies. Figure 4 (a to c) illustrates

the inequality of global and regional per capita policy

costs, expressed as the mean log deviation (MLD),

where higher MLD values indicate greater inequality.

This metric provides comprehensive insights into how

various scenarios inﬂuence inequality within and between

regions, enhancing our understanding of the broader

economic impacts of carbon pricing strategies.

The FullTech scenario, characterized by a relatively low

carbon price trajectory, results in the lowest levels of

inequality (see Figure 4a). In contrast, scenarios with

limited CDR deployment lead to substantial increases

in inequality, with disparities rising by 13.2% to 40.7%

compared to FullTech. These gaps are most pronounced

in the years immediately following the net-zero target,

peaking between 9.8% and 28.9% by 2100 (see Figure S7

in the appendix). Notably, within-region inequality is

greater than between-region inequality, highlighting

that national factors – such as policy design, economic

structure, and CDR capacity – drive inequality more than

interregional dierences.

A comparison of OECD and non-OECD regions reveals

a distinct pattern, where OECD countries exhibit

consistently lower levels of inequality across all scenarios.

Under limited CDR deployment, inequality in OECD

regions rises modestly, by 10.8% to 32.7%. In contrast,

non-OECD regions experience more pronounced

increases, ranging from 12.4% to 44.6%. This disparity

suggests that OECD economies are more resilient to the

economic impacts of decarbonization, beneﬁting from

established infrastructure, diversiﬁed energy systems,

and greater technological capacity. Non-OECD regions,

however, face greater challenges under limited CDR

scenarios, hindered by weaker economic resilience,

limited technological capabilities, and structural barriers

that impede scaling up alternative mitigation strategies.

Further distinctions arise when comparing net fossil fuel

producers and consumers. Net fossil fuel consumers

consistently show higher levels of inequality across

all scenarios, driven by their greater vulnerability to

decarbonization eorts. Reliance on fossil fuel imports

exposes these regions to higher economic costs.

External energy dependency leads to elevated transition

expenses and heightened susceptibility to energy price

ﬂuctuations and supply disruptions. Conversely, net fossil

fuel producers, while initially displaying lower inequality,

experience a marked increase – rising by 26.3% to 78.7%

under limited CDR scenarios – compared to a smaller

increase of 12% to 41.1% for consumers. This underscores

the particular vulnerability of fossil fuel-producing

regions, whose economies heavily depend on extraction

and export revenues. CDR restrictions intensify these

challenges, complicating eorts to reduce emissions

while maintaining economic stability.

These ﬁndings underscore the crucial importance of

equitable access to CDR technologies in mitigating

economic inequalities associated with decarbonization

(Yuwono et al. 2023). Without widespread CDR

deployment, some regions could face severe economic

disadvantages in their pursuit of climate targets. The

disparities highlight the need for inclusive global

climate strategies that address both environmental

objectives and economic well-being, ensuring the

transition to a low-carbon future does not exacerbate

existing inequalities.

18Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure 4. Global and regional inequality in per capita policy costs.

Source: Authors.

a. Global inequality in per capita policy costs across dierent decarbonization scenarios.

b. Inequality in per capita policy costs between OECD and non-OECD regions.

c. Inequality in per capita policy costs between net fossil fuel consumers and net fossil fuel producers. All panels present the mean log deviation (MLD) of

inequality in per capita policy costs, decomposed into intraregional (within-region) and interregional (between-region) components. The intraregional

component (in orange) represents disparities within regions, while the interregional component (in green) represents dierences between regions.

MLD is used as a measure of inequality, with higher values indicating greater inequality in policy costs. It captures disparities within individual regions

and across dierent regions, providing insights into how dierent scenarios aect both local and global equity in climate policy costs. See Table S7 for

details on regional classiﬁcations.

19Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

3.5 Implications

of Limited CDR on

Household Food and

Energy Demand

Beyond their impact on mitigation policy costs, rising

carbon prices can have profound microeconomic eects,

particularly through higher food and energy costs (see

Figure S6 in the Supplementary section). Elevated carbon

prices increase production costs, which are passed on to

consumers, leading to higher prices for essential goods

like food and energy (MacDonald and Parry 2024). In

regions facing steep carbon price increases, households

may struggle to maintain food and energy consumption,

resulting in demand deﬁcits as they adjust to rising costs.

Figure 5 (a and b) illustrates these regional impacts under

constrained CDR scenarios. Our results indicate that the

LimCDR+Bio100 scenario shows the most pronounced

reductions in food and energy demand. In this scenario,

food demand in Sub-Saharan Africa declines by up to 9%

by 2055, while Southeast Asia experiences reductions

ranging from 3.5% to 9%. These results reﬂect regional

economic challenges, with rising costs forcing households

with limited budgets to adjust their consumption

patterns. The reductions in food demand are largely

driven by changes in non-staple food consumption,

which is typically more elastic than staple foods. This

often leads households to substitute higher-cost items,

such as meats or processed foods, with more aordable

staples, or to reduce discretionary food purchases

altogether. Residential energy demand reductions are

substantial, with Central Asia, South America, and parts

of Africa experiencing declines of 2.5%-5.7% due to

carbon price increases tied to limited CDR availability.

These reductions are driven by the increased cost of

energy services, which forces households to adjust their

consumption patterns, particularly for non-essential or

energy-intensive activities. In regions with lower incomes,

these adjustments often reﬂect a reduction in energy

suciency, leading to limited access to basic energy

services like heating, cooling and lighting. These socio-

economic vulnerabilities associated with constrained

mitigation options, where households are forced to adapt

by lowering their overall energy use, can potentially

compromise well-being and quality of life.

Overall these reductions underscore the challenges for

regions with limited access to mitigation technologies,

as higher carbon prices strain essential services like

heating, cooking, lighting and food. The socio-economic

vulnerabilities exacerbated under constrained CDR

scenarios emphasize the critical need for equitable

access to carbon removal technologies and ﬁnancial

support to avoid deepening regional inequalities.

20Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure 5. Impact of limited CDR on household energy and food demand.

Source: Authors.

a. Impact of constrained CDR on residential energy demand.

b. Impact of constrained food demand, showing deviations from FullTech. Both graphs show deviations from the FullTech scenario for the net-zero year

(2055).

21Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

4. Discussion and

Conclusion

Our study highlights the pivotal role of CDR technologies in achieving

the 1.5°C Paris Agreement climate target. It also illustrates the profound

implications of CDR availability on global and regional economic outcomes.

The scenarios demonstrate that variations in CDR deployment could lead

to signiﬁcant disparities in carbon prices and economic inequalities across

regions. In essence, the limited availability of CDR technologies not only

hampers the eectiveness of regional emission reductions but also results in

elevated carbon prices, imposing additional ﬁnancial burdens on regions with

limited access to advanced mitigation technologies.

Under constrained CDR scenarios, developing regions

such as Africa and parts of Asia face disproportionately

higher carbon prices. For instance, under the

LimCDR+Bio100 scenario, Eastern Africa faces carbon

prices as high as $3,059/tCO2 by 2100, while South Asia

reaches $2,909/tCO2. These exceptionally high carbon

prices not only highlight stark regional inequalities,

they also raise critical concerns about the feasibility of

achieving region-speciﬁc emission targets given the

limited ﬁnancial and technological capacities of these

regions to adapt to high mitigation costs. Such burdens

can signiﬁcantly hinder economic development and

eorts to reduce poverty (Shang 2023; Soergel, Kriegler,

Bodirsky et al. 2021). The disparities between regional

capabilities emphasize the need for mechanisms like

international climate ﬁnance, technology transfer, and

capacity-building initiatives to support vulnerable regions

in the global decarbonization eort (Soergel, Kriegler,

Weindl et al. 2021; Rogelj et al. 2018; Honegger et al.

2021).

Our analysis also reveals that per capita policy cost

inequality is more pronounced within regions than

between them. This suggests that national policies,

economic structures, and capacities for CDR deployment

signiﬁcantly inﬂuence the distributional impacts of

decarbonization eorts. Further, the dierence in

inequalities observed between net fossil fuel producers

and consumers under constrained scenarios highlight

the contextual challenges dierent economies might

face. This highlights the importance of tailored policy

approaches that consider regional contexts and promote

just transitions (Klinsky et al. 2017).

The microeconomic impacts of limited CDR availability

also have signiﬁcant social implications, particularly in

regions already facing socio-economic vulnerabilities.

Our results show that rising carbon prices can drive

up production costs for essential goods like food

and energy, reducing access to these services and

exacerbating issues such as food security in Sub-Saharan

Africa and energy poverty in Central Asia and South

America (MacDonald and Parry 2024; Soergel, Kriegler,

Bodirsky et al. 2021). This calls for social considerations

to be integrated into climate policies to prevent

further inequalities and safeguard development goals

(Leichenko and Silva 2014). Additionally, the vulnerability

of developing countries, often constrained by limited

resources and technological capacity, raises concerns

about stalled climate ambitions and potential economic

destabilization without adequate ﬁnancial and institutional

support (Rickels et al. 2021). Ensuring equitable access

to a broad portfolio of mitigation technologies, including

CDR, is essential to avoid worsening regional economic

22Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

disparities and to foster inclusive participation in global

decarbonization eorts (Yuwono et al. 2023; Honegger,

Michaelowa, and Roy 2021).

Overall, our study highlights the need to integrate

CDR within broader climate policies that ensure global

equity. While CDR technologies are crucial, they

should not displace immediate emission reductions

but rather complement them to help achieve climate

goals more eectively and equitably (Fuss et al. 2014).

The deployment of a full suite of CDR technologies –

alongside aggressive emission reduction strategies –

will be essential for meeting global climate targets and

minimizing economic disparities across regions (Geden,

Peters, and Scott 2019).

In conclusion, our ﬁndings stress the importance of

designing climate policies that address regional capacity

and resource disparities while keeping mitigation eorts

central to the global transition to a low-carbon future.

Without inclusive and widespread CDR deployment, the

costs of achieving climate goals may disproportionately

fall on regions with fewer resources, intensifying existing

inequalities. Policymakers must consider the distributional

impacts of climate strategies and promote international

cooperation to ensure that the transition to a low-carbon

future is both eective and just. The policy cost inequalities

identiﬁed in constrained CDR scenarios underscore the

critical importance of distributing resources equitably,

ensuring that no region is left behind in the global eort

to limit warming to 1.5°C (IPCC 2023).

23Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

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28Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Supplementary

Figure S1. Comparison of CDR technologies with AR6 CDR projections for C1 and C2 class scenarios.

Source: Authors and Assessment Report 6 (AR6) Scenario database.

Notes: The gray lines represent the range of the AR6 model projections for carbon dioxide removal, while the colored lines show the results for the

six scenarios analyzed in this study. Note that the y-axis scales dier across the panels to illustrate the relative projections of our modeling CDR

technology output compared to the AR6 model projections. In addition, “n” represents the sample size of scenarios extracted from the AR6 database.

29Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure S2. Comparison of CCS and Bioenergy with AR6 projections for C1 and C2 class scenarios.

Source: Authors and Assessment Report 6 (AR6) Scenario database.

Notes: The gray lines represent the range of the AR6 model projections, while the colored lines depict results from the six scenarios analyzed in this

study. The “n” represents the sample size of scenarios extracted from the AR6 database.

Figure S3. Comparison of global temperature with AR6 projections for C1 and C2 class scenarios.

Source: Authors and Assessment Report 6 (AR6) Scenario database.

Notes: The gray lines represent the range of the AR6 model projections, while the colored lines depict the results from the six scenarios analyzed in this

study. The “n” represents the sample size of scenarios extracted from the AR6 database. The black line represents the “Baseline” scenario, illustrating

an unmitigated pathway with steadily increasing global temperatures.

30Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure S4. Regional distribution of residual emissions across GCAM’s 32 regions.

Source: Authors.

Notes: The top panels show emissions in 2055, while the bottom panels display emissions in 2100 for six dierent decarbonization scenarios. The

intensity of the shading indicates the scale of residual emissions, with darker regions representing higher levels of remaining emissions post-mitigation

eorts.

31Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure S5. Regional distribution of residual emissions across GCAM’s 32 regions for various decarbonization scenarios.

Source: Authors.

Notes: The top panels represent residual emissions in 2055, while the bottom panels show emissions in 2100. Darker shading indicates higher residual

emissions.

32Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure S6. Sectoral residual emissions and carbon dioxide removal (CDR) technology deployment under six

decarbonization scenarios relative to the FullTech scenario.

Source: Authors.

Notes: Positive bars indicate an increase in emissions or CDR deployment compared to FullTech, while negative bars represent a decrease. GtCO2e =

gigatons of CO2 equivalent.

33Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure S7.

Source: Authors.

Notes: Panel (a) shows the mean log deviation (MLD) of per capita policy cost inequality from 2025 to 2100 across six dierent scenarios. Panel (b)

highlights the percentage dierences in inequality between constrained CDR scenarios and the FullTech scenario, distinguishing between the periods

before and after the net-zero year. This illustrates how limitations on CDR technologies inﬂuence inequality, particularly during the net-zero transition

period.

34Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure S8.

Source: Authors.

Notes: Panel (a) illustrates the dierence in regional per capita residential energy expenditure relative to the FullTech scenario. Panel (b) illustrates the

dierence in regional per capita residential energy expenditure relative to the FullTech scenario. Both graphs highlight regions that experience greater

household costs under limited CDR deployment.

35Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure S9. Food demand (staple vs. non-staple) from 2020 to 2100.

Source: Authors

Notes: Panel (a) shows total food demand (in kilocalories [kcal]/person/day) from 2020 to 2100 for staple and non-staple food types across dierent

scenarios (FullTech, LimCDR, Bio100, LimCDR+Bio100, CCS50, and LimCDR+CCS50). Panel (b) illustrates the percentage food demand dierence for

each scenario relative to the FullTech baseline, plotted from 2020 to 2100. Both panels provide insights into food demand trends and the shifts in

dierent climate policy scenarios over time. kcal = kilocalories.

36Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Figure S10.

Source: Authors.

Notes: Panel (a) shows the residential energy demand (in MWh/person) by sector (Cooling, Heating, Others) from 2020 to 2100 across dierent

scenarios (FullTech, LimCDR, Bio100, LimCDR+Bio100, CCS50, and LimCDR+CCS50). Each bar represents the breakdown of energy demand into

dierent energy services over time. MWh = megawatthours. Panel (b) illustrates the percentage dierence in residential energy demand for each

scenario relative to the FullTech baseline, plotted from 2020 to 2100. Both panels provide insights into the trends in energy demand and the impact

of various climate mitigation scenarios on residential energy consumption over time.

37Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Table S1. Greenhouse gas emission projections and decarbonization targets by region.

Region 2025 2030 2050 2100 Net-zero

year

5% post-2030

decarbonization rate

Argentina 386.218 349.01 0 0 2050 -

Australia and

509.313 499.54 0 0 2050 -

Brazil 1,167.254 1,197 0 0 2050 -

Canada 573.858 448.28 0 0 2050 -

China 15,682.03 16,452.58 5,484.192 02060 -

Colombia 186.741 169.54 108.582 22.565 -Yes

EU 2,960.065 2,522.7 0 0 2050 -

India 4,097.473 4,785.224 1,952.159 02070 -

Indonesia 1,046.709 1,149.2 723.741 86.318 -Yes

Japan 923.049 760.32 0 0 2050 -

Mexico 639.969 654.04 388.131 75.904 -Yes

Russia 1,958.221 2,005.37 1,019.85 129.26 -Yes

South Africa 458.29 440.643 0 0 2050 -

South Korea 629.283 534.728 0 0 2050 -

USA 4,315.465 3,453.87 0 0 2050 -

Africa

– Eastern

631.957 700.21 803.103 549.49 -Yes

Africa

– Northern

807.859 836.17 609.385 134.67 -Yes

Africa

– Southern

445.575 463.4 304.275 82.689 -Yes

Africa

– Western

1,107.785 1,190.35 1,338.661 869.17 -Yes

Central

America and

Caribbean

345.188 357.53 237.669 58.599 NA Yes

38Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Region 2025 2030 2050 2100 Net-zero

year

5% post-2030

decarbonization rate

Central Asia 765.873 731.61 445.272 67.152 NA Yes

Europe

– Eastern

387.035 369.45 214.261 34.547 NA Yes

Europe

– Non-EU

662.07 689.59 398.719 62.682 NA Yes

European

Free Trade

Association

79.978 55.34 21.151 1.774 NA Yes

Middle East 2,560.666 2,520.909 1,571.108 297.83 NA Yes

Pakistan 432.242 461.47 423.813 175.37 NA Yes

South

America

– Northern

145.753 143.04 88.038 16.437 NA Yes

South

America

– Southern

488.024 512.2 323.895 61.881 NA Yes

South Asia 393.615 453.9 379.135 136.48 NA Yes

Southeast

Asia

2,103.823 2,202.25 1,490.3 307.24 NA Yes

Notes: This table presents projected greenhouse gas emissions (in MtCO₂e) for selected regions in 2025, 2030, 2050, and 2100. The data includes

each region’s targeted net-zero year, where applicable, and an indication of whether a decarbonization rate of at least 5% is expected post-2030.

Regions with a marked “Yes” in the ﬁnal column are projected to achieve a signiﬁcant reduction in emissions beyond 2030.

Table S1. (continued)

39Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Table S2. Projected carbon prices and percentage increases relative to the FullTech scenario across regions and

scenarios (Bio100, CCS50, LimCDR, LimCDR+Bio100, LimCDR+CCS50) for 2055 and 2100.

Percentage increase compared to FullTech

Region Year FullTech

($2020/tCO2)

Bio100 CCS50 LimCDR LimCDR+

Bio100

LimCDR+

CCS50

Africa – Eastern 2055 575.8 140.3 139.1 97.1 147.9 139.5

Africa

– Northern

2055 734.8 129.3 123.8 105.7 133.6 124.0

Africa

– Southern

2055 598.7 135.8 119.9 102.3 142.0 120.1

Africa – Western 2055 479.6 123.1 114.3 106.5 127.0 114.5

Argentina 2055 539.3 136.6 128.3 113.2 145.5 128.6

Australia and NZ 2055 586.4 133.3 125.8 112.0 141.9 126.4

Brazil 2055 365.5 124.8 114.3 108.6 128.4 114.5

Canada 2055 516.7 106.4 98.8 97.3 109.6 99.1

Central America

and Caribbean

2055 530.9 138.2 133.2 99.8 145.8 133.6

Central Asia 2055 614.8 139.5 141.3 113.8 153.5 141.6

China 2055 705.9 134.5 133.1 110.1 142.4 133.4

Colombia 2055 429.3 149.6 119.4 92.5 158.9 120.5

EU 2055 736.3 137.7 128.2 109.1 144.5 128.5

Europe

– Eastern

2055 496.6 114.1 102.4 103.2 117.6 102.7

Europe

– Non-EU

2055 650.0 133.5 115.2 100.8 138.1 115.5

European

Free Trade

Association

2055 316.5 170.9 164.0 87.5 188.4 243.6

India 2055 459.1 121.7 109.6 96.4 125.6 109.8

Indonesia 2055 604.4 119.3 112.2 97.2 124.3 112.5

40Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Percentage increase compared to FullTech

Japan 2055 576.4 135.1 89.4 69.6 144.1 87.7

Mexico 2055 504.2 140.1 136.1 94.7 150.8 136.4

Middle East 2055 627.8 131.6 129.7 105.8 137.6 130.0

Pakistan 2055 941.9 136.0 136.6 115.8 140.9 137.1

Russia 2055 553.1 114.5 101.7 99.2 117.1 101.9

South Africa 2055 814.6 142.8 128.5 112.7 149.2 128.8

South America

– Northern

2055 596.5 128.1 117.5 101.7 139.1 117.6

South America

– Southern

2055 487.7 129.1 122.8 104.7 136.1 123.0

South Asia 2055 778.6 143.5 133.6 114.5 149.6 134.0

South Korea 2055 626.1 140.2 132.2 109.2 148.4 132.5

Southeast Asia 2055 546.2 130.9 121.1 99.0 136.0 121.4

USA 2055 591.1 146.2 149.7 110.6 167.0 150.1

Africa – Eastern 2100 756.6 287.3 295.2 244.5 404.3 271.3

Africa

– Northern

2100 872.9 250.4 250.0 213.6 326.4 231.2

Africa

– Southern

2100 778.2 263.6 265.8 225.5 356.3 247.3

Africa – Western 2100 766.0 254.5 256.9 218.8 342.6 238.9

Argentina 2100 305.7 298.1 348.8 278.6 468.5 329.8

Australia and NZ 2100 458.6 299.8 347.4 311.4 489.3 352.3

Brazil 2100 396.6 309.5 350.3 298.9 489.3 342.4

Canada 2100 582.4 225.8 219.6 179.9 291.9 223.1

Central America

and Caribbean

2100 537.4 225.0 228.7 187.3 304.8 222.4

Table S2. (continued)

41Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Percentage increase compared to FullTech

Central Asia 2100 477.6 298.6 335.6 302.7 478.2 341.9

China 2100 506.1 261.3 290.5 238.1 403.8 286.4

Colombia 2100 446.0 296.6 347.4 301.2 491.3 367.1

EU 2100 745.3 245.9 243.6 199.2 326.7 233.5

Europe

– Eastern

2100 649.9 203.5 194.2 176.4 256.7 189.6

Europe

– Non-EU

2100 800.3 251.6 238.7 209.3 333.4 224.9

European

Free Trade

Association

2100 638.9 255.7 243.2 188.4 338.7 235.4

India 2100 605.7 210.7 207.9 170.6 265.1 204.1

Indonesia 2100 677.2 212.0 214.2 184.8 255.4 220.6

Japan 2100 635.4 262.4 247.4 207.6 371.8 245.4

Mexico 2100 544.2 245.6 249.4 212.5 340.9 267.7

Middle East 2100 743.9 219.5 212.7 190.4 280.4 206.0

Pakistan 2100 874.3 263.4 269.0 218.2 365.0 242.7

Russia 2100 573.7 228.0 224.6 191.1 302.1 225.1

South Africa 2100 696.9 220.8 220.7 178.2 290.0 211.0

South America

– Northern

2100 462.2 308.9 360.2 317.2 480.8 375.6

South America

– Southern

2100 392.8 304.1 352.7 291.7 483.6 351.2

South Asia 2100 828.8 252.3 256.0 218.2 350.9 241.3

South Korea 2100 717.1 233.7 237.4 194.6 315.8 243.0

Southeast Asia 2100 639.9 222.4 210.1 189.6 277.0 202.6

USA 2100 483.4 253.7 276.3 232.7 387.2 274.3

Table S2. (continued)

42Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Table S3. Direct air capture (DAC) cost assumptions per ton of CO2.

Technology Units 2020 2050

High temperature DAC with natural gas $2020 per tCO2447.8 172.3

Low temperature DAC with heat pumps $2020 per tCO2625.7 291.2

High temperature DAC with electricity $2020 per tCO2599.6 350.9

Source: Fuhrman et al. (2020).

Notes: Costs are derived from GCAM assumptions for DAC non-energy costs and energy coecients, as well as endogenously calculated GCAM

energy costs. Costs are linearly interpolated between the years shown.

Table S4. Weathering potential by GCAM region (GtCO2).

GCAM region(s) Weathering potential (GtCO2) Fraction relative to global

removal potential (%)

Australia and NZ 0.035 1%

Brazil 0.761 22%

Canada 0.001 0%

Central Asia 0.003 0%

China 0.435 13%

Europe Non EU 0.008 0%

Europe – Eastern 0.067 2%

European Free Trade Association 0.001 0%

EU 12 0.056 2%

EU 15 0.12 4%

Indonesia 0.371 11%

India 1.568 46%

Japan 0.022 1%

South Korea 0.001 0%

43Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

GCAM region(s) Weathering potential (GtCO2) Fraction relative to global

removal potential (%)

Argentina; Central America and

Caribbean; Colombia; South America –

Northern; South America – Southern

0.278 8%

Middle East 0.005 0%

Mexico 0.015 0%

Africa – Northern 0.006 0%

Southeast Asia 0.757 22%

Pakistan 0.01 0%

Russia 0.114 3%

South Africa 0.002 0%

Africa – Eastern; Africa – Southern; Africa

– Western 0.252 7%

Europe – Non-EU 0.012 0%

USA 0.056 2%

Source: Fuhrman et al. (2023).

Notes: The table outlines the carbon dioxide (CO2) removal potential through enhanced weathering across various GCAM regions. Weathering

potential refers to the amount of CO2 that could be sequestered from the atmosphere through this process. The table includes the weathering potential

in gigatons of CO2 (GtCO2) for each region, as well as the fraction of the global removal potential each region represents. These values help to assess

the role of dierent regions in contributing to global CO2 removal eorts through enhanced weathering.

Table S4. (continued)

44Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Table S5. Power sector biomass with carbon capture and storage (CCS) cost assumptions for 2020 and 2050.

Technology Capacity factor Cost component 2020 2050

Biomass (Conv CCS) 0.8 Overnight capital cost ($2020/kW) $7,437 $6,001

  Fixed O&M ($2020/kW/yr) $141 $136

  Variable O&M ($2020/MWh) $10 $9

Biomass (IGCC CCS) 0.85 Overnight capital cost ($2020/kW) $8,472 $6,490

  Fixed O&M ($2020/kW/yr) $200 $179

  Variable O&M ($2020/MWh) $10 $9

Notes: Costs are derived from GCAM assumptions for both conventional biomass (Conv CCS) and integrated gasiﬁcation combined cycle (IGCC

CCS) technologies. Key cost components include overnight capital cost, ﬁxed operations and maintenance (O&M), and variable O&M costs. Costs

are presented in $2020 values and are linearly interpolated between the years shown. Capacity factors reﬂect the percentage of time the plants are

expected to operate at full capacity. These cost assumptions are critical for assessing the economic feasibility of biomass CCS deployment under

various decarbonization scenarios. kW = kilowatt; MWh = megawatthour; kW/yr = kilowatts per year.

Table S6. Cost assumptions for cellulosic ethanol and FT biofuels with carbon capture and storage (CCS) technologies for

2020 and 2050.

Technology Variable 2020 2050

Cellulosic ethanol CCS (level 1) GJ biomass / GJ liquid fuel 2.14 2.03

Non-energy cost ($2020/GJ) $17 $15

Cellulosic ethanol CCS (level 2) GJ biomass / GJ liquid fuel 2.26 2.14

Non-energy cost ($2020/GJ) $23 $19

FT biofuels CCS (level 1) GJ biomass / GJ liquid fuel 2.04 1.95

Non-energy cost ($2020/GJ) $30 $25

FT biofuels CCS (level 2) GJ biomass / GJ liquid fuel 2.16 2.07

Non-energy cost ($2020/GJ) $31 $26

Notes: This table outlines the key assumptions for cellulosic ethanol and Fischer-Tropsch (FT) biofuels production with integrated Carbon Capture and

Storage (CCS) for both level 1 and level 2 technologies. The variables captured include the amount of biomass required per unit of liquid fuel produced

(GJ biomass per GJ liquid fuel) and non-energy production costs ($2020/GJ). GJ = gigajoules.

45Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

Table S7. Assumptions for biochar production and carbon sequestration.

Metric Value Units

Non-energy cost 45.93 $2020 per ton of feedstock

Biomass input 3.65 Tons of switchgrass per ton of biochar

Natural gas input 211.19 MJ per dry ton of biochar

Syngas co-product 20,095 MJ per dry ton of biochar

Net syngas co-product 19,884 MJ per dry ton of biochar

Application rate 10-20 Tons of biochar per hectare

Yield improvements (tropical irrigated) 12 Percentage

Yield improvements (tropical rainfed) 19 Percentage

Yield improvements (temperate irrigated) 10 Percentage

Yield improvements (temperate rainfed) 15 Percentage

Carbon sequestered 70 Percentage

Source: Bergero et al. (2024).

Notes: This table details key metrics for biochar production, including costs ($2020/ton), resource inputs, co-product outputs,

application rates, yield improvements, and carbon sequestration eciency. MJ = megajoules.

Table S8. Fossil fuel consumption and production status across GCAM regions.

GCAM region Fossil fuel consumers/producers OECD vs. non-OECD

European Free Trade Association Consumer OECD

Australia and NZ Producer OECD

Canada Producer OECD

Japan Consumer OECD

Europe – Eastern Consumer Non-OECD

EU-12 Consumer OECD

Europe – Non-EU Consumer OECD

EU-15 Consumer OECD

USA Producer OECD

Taiwan Consumer Non-OECD

46Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

GCAM region Fossil fuel consumers/producers OECD vs. non-OECD

Colombia Consumer Non-OECD

South Korea Consumer Non-OECD

Argentina Consumer Non-OECD

Central America and Caribbean Consumer Non-OECD

South America – Southern Consumer Non-OECD

South Africa Consumer Non-OECD

Mexico Consumer Non-OECD

Brazil Consumer Non-OECD

Central Asia Producer Non-OECD

South Asia Consumer Non-OECD

Pakistan Consumer Non-OECD

Africa – Eastern Consumer Non-OECD

Africa – Southern Consumer Non-OECD

South America – Northern Producer Non-OECD

Indonesia Producer Non-OECD

Africa – Northern Producer Non-OECD

Russia Producer Non-OECD

Middle East Producer Non-OECD

Southeast Asia Consumer Non-OECD

Africa – Western Consumer Non-OECD

India Consumer Non-OECD

China Consumer Non-OECD

EU Consumer OECD

Notes: This table categorizes regions according to whether they are fossil fuel producers or consumers, as well as their economic

grouping within the OECD or non-OECD. Regions classiﬁed as producers are signiﬁcant exporters or extractors of fossil fuels,

whereas consumers rely heavily on imports or the domestic consumption of fossil fuels. The OECD designation refers to regions

that are part of the Organisation for Economic Co-operation and Development, representing more developed economies, while

non-OECD refers to regions outside this group, often encompassing developing or emerging economies. This classiﬁcation provides

insight into the energy dependencies and economic structures of dierent global regions, which is crucial for assessing their role in

climate mitigation and decarbonization eorts.

Supplementary Table S8. (continued)

47Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

About the Authors

Raphael Apeaning

Raphael Apeaning is the Lead Researcher in the Climate and Sustainability program at

KAPSARC. An integrated assessment modeler with expertise in energy transition strategies and

policy, he previously worked as a researcher at the Institute for Responsible Carbon Removal

in Washington, DC. There, he played a key role in expanding the portfolio of carbon dioxide

removal technologies for climate modeling and developing market mechanisms for negative

emission technologies.

Puneet Kamboj

Puneet is a Lead Researcher in the Climate and Sustainability program with over nine years of

policy research experience at renowned global think tanks. His expertise includes integrated

assessment modeling, climate change policies, clean energy technologies, and the power

sector. Prior to joining KAPSARC, he contributed to several global think tanks and co-edited an

anthology on India’s coal sector. Spanning 18 chapters, the book draws from leading experts

to explore all aspects of coal’s future in India. Puneet has an extensive portfolio of published

papers, policy briefs, and reports. As an independent scholar, he has written for the G20 and

prominent national newspapers. He holds a Master of Technology in renewable energy from

TERI University in New Delhi, India.

Mohamad Hejazi

Mohamad is the Program Director for the Climate and Sustainability Program at KAPSARC.

He also leads the CAMP project, focusing on climate change research, climate impacts

and adaptation, climate mitigation, IAM, and the energy-water-land nexus. Prior to joining

KAPSARC, Mohamad worked as a Senior Research Scientist at the U.S. Department of

Energy’s Paciﬁc Northwest National Laboratory, where he served as the principal investigator

for the Global Change Intersectoral Modeling System project, a multi-million-dollar project

with over 40 interdisciplinary researchers across many institutions. Mohamad has led and

contributed to projects with the World Bank, Inter-American Development Bank, U.S.-AID,

U.S.-EPA, USGS, NASA, and NSF-INFEWS. He has authored over 100 journal publications and

served as a contributing author to the Fourth U.S. National Climate Assessment, and the AR6

Intergovernmental Panel on Climate Change (IPCC) WG III report on the mitigation of climate

change. Mohamad holds a B.S. and M.S. from the University of Maryland, College Park, and a

Ph.D. from the University of Illinois, Urbana-Champaign.

48Limiting Carbon Dioxide Removal Could Exacerbate Global Economic Inequality

About the Project

This study is a part of the Climate Adaptation and Mitigation Partnership

(CAMP) project. The CAMP project is timely and crucial for Saudi Arabia given

the mounting risks associated with climate change impacts, the urgency

of pushing toward a low-carbon future while maintaining economic growth

nationally, and the potential economic ramiﬁcations of global mitigation

eorts on the Saudi energy sector and economy. Against this backdrop, the

CAMP project investigates (1) the climate conditions in Saudi Arabia, (2) the

sectoral impacts and the role of adaptation measures, and (3) the pathways

of the Saudi economy to achieve a low-carbon future or climate neutrality by

the mid-century. The study will also (4) adopt the circular carbon economy

concept in characterizing the Saudi government’s eorts to decarbonize its

own economy while meeting its growth aspirations.