Deployment expectations of multi-gigatonne scale carbon removal could have adverse impacts on Asia's energy-water-land nexus

The study examines how varying degrees of reliance on carbon dioxide removal (CDR) could affect Asia’s energy, land, and water systems while pursuing Paris-consistent climate goals. With the 1.5 °C carbon budget rapidly shrinking, CDR is seen as complementary to deep emissions cuts, yet overreliance may cause mitigation deterrence, prolong fossil fuel use, and stress land and water resources. The paper addresses the quantitative research question: what is the extent of impacts on a country’s or region’s energy–land–water nexus in Asia under expectations of multi-gigatonne CDR deployment by mid-century? The purpose is to inform balanced policy strategies that prioritize rapid decarbonization while deploying CDR where most viable and to clarify trade-offs under different CDR availability levels.

Prior work highlights that achieving 1.5 °C often entails large-scale CDR (>10 GtCO₂yr⁻¹ by mid-century), but evidence on energy–land–water trade-offs under different CDR reliance is scarce and has been largely philosophical or qualitative. Policy pathways frequently treat emissions reduction and CDR as interchangeable under a single carbon price, risking deferred near-term mitigation. Previous modeling often constrained CDR by limiting CCS or biomass supply indirectly, and focused predominantly on land-based CDR (BECCS, AR), with limited coverage of chemical/geochemical options (DACCS, biochar, ERW, DORCS). Asia is expected to host a large share of future global CDR (without equity considerations), yet quantitative assessments of energy–land–water implications across Asian countries remain limited. This study responds by explicitly capping actual CDR deployment, keeping CCS/biomass for other uses, and including a wider set of CDR approaches.

The authors use a modified Global Change Assessment Model (GCAM-TJU; based on GCAM5.4) to assess Asia under the Shared Socioeconomic Pathway 2 (SSP2). They target a stylized net-zero GHG pathway for Asia consistent with 1.5 °C, with 2030 GHG emissions ~45% below 2019 levels, peaking before 2025 and reaching net zero around mid-century. Four scenarios are modeled: (1) HIGH: six CDR options (AR, Biochar, BECCS, DACCS, DORCS, ERW) available from 2025 with no cap; gross CDR in Asia endogenously reaches ~12 GtCO₂yr⁻¹ by 2050. (2) MODERATE: only BECCS and AR available; global BECCS capped at 2 GtCO₂yr⁻¹, Asia’s BECCS averages 1.8 GtCO₂yr⁻¹ (2025–2050); total gross CDR reaches ~2.3 GtCO₂yr⁻¹ by 2050. (3) LOW: only AR; novel CDR constrained to 0 GtCO₂yr⁻¹; total gross CDR ~0.5 GtCO₂yr⁻¹ by 2050. (4) REFERENCE: no new climate policy; AR only. GCAM-TJU extends standard GCAM by adding biochar, ERW, and DORCS to the existing AR/BECCS/DACCS suite, with technology detail provided in supplementary notes. The modeling tracks energy supply and demand, sectoral emissions (fossil and industry and bio-derived), land allocation, water use by sector (including DACCS and bioelectricity-CCS), fertilizer demand, abatement costs, stranded assets, capacity additions, and timing of domestic net-zero CO₂ across Asian countries/regions. Sensitivity analyses and comparisons to prior Asia-based IAM studies are provided in supplementary material.

• High CDR reliance (HIGH) sustains fossil use and slows clean transitions. By 2050, unabated fossil fuels exceed 30% of Asia’s primary energy under HIGH versus <10% under MODERATE/LOW; at least an additional ~70 EJ/yr of coal and natural gas are consumed in end-use sectors under HIGH compared to MODERATE/LOW. Final energy in HIGH is only 5% below REFERENCE by 2050, versus ~35% reductions under MODERATE/LOW.
• Marginal abatement costs (carbon prices) are lower under HIGH due to reliance on CDR (notably DACCS as a backstop), and considerably higher under MODERATE/LOW, which require earlier, deeper decarbonization.
• Sectoral transitions: Under HIGH, no Asian country exceeds 15% electrified transport share by 2050 (e.g., Central Asia 12.9%, Japan 8.64%, China 4.5%, India 3.75%); under MODERATE/LOW, electrified transport shares can reach 42–47% in leading regions, with China and India ~25–35%. Building final energy drops more under MODERATE/LOW (e.g., by 2050: Central Asia ~38.8%, South Asia ~50%, China ~34%) than under HIGH (~22–25%). Renewables’ primary energy shares in 2050 are higher under MODERATE (China 33%, India 45%) than HIGH (China 17%, India 27%).
• Emissions: Total positive GHG emissions in 2050 are lower under MODERATE (11 GtCO₂e/yr) and LOW (13) than HIGH (16). Excluding biogenic CO₂, GHGs in 2050 are ~12.95 (HIGH), 5.38 (MODERATE), and 5 GtCO₂e/yr (LOW). Under HIGH, residual fossil fuel and industry (FFI) emissions by 2050 exceed 2 GtCO₂/yr (industry) and 3 GtCO₂/yr (transport), versus <0.5 GtCO₂/yr each under MODERATE/LOW. Regional positive emissions >1 GtCO₂/yr by 2050 include China, India, Middle East, Southeast Asia under both HIGH and LOW (with different magnitudes).
• Negative emissions distribution: Under HIGH, gross removals by 2050 are concentrated in China (~6 GtCO₂/yr), India (~1.8), Middle East (~0.9). Under MODERATE, these fall to ~1.2, 0.5, and 0.08 GtCO₂/yr respectively. Country preferences vary: DACCS dominates in China, Central Asia, Middle East; BECCS and biochar are relatively prominent in India and Southeast Asia; ERW significant in China, India, Southeast Asia; DORCS is least favored due to cost.
• Net-zero timing and foreign CDR: HIGH can delay domestic net zero; several countries may opt to purchase foreign CDR credits rather than achieve domestic net-zero CO₂ by 2050. Under MODERATE/LOW, purchasing foreign CDR becomes economically unattractive, and countries advance or maintain domestic net-zero timing before 2050.
• Stranded assets and investments: Premature retirements of fossil power (without CCS) are 1100 GW (HIGH), 1260 GW (MODERATE), 1305 GW (LOW). Cumulative stranded costs (2015–2050) reach ~$9.5 trillion in LOW, roughly double HIGH. From 2046–2050, new decarbonization capacity and investments are ~916 GW and $2.6T (HIGH) vs ~2322 GW and $7.6T (LOW). Solar provides 30–35% of new capacity; cost shares led by solar and nuclear (20–30% each).
• Land, water, fertilizer: HIGH allocates more land annually to bioenergy crops than MODERATE/LOW; food and non-food cropland allocations are slightly higher under HIGH. Under HIGH, BECCS water for bioelectricity CCS reaches ~3.6 km³/yr by 2050 (vs ~1.7 under MODERATE); electricity-generation water use in MODERATE/LOW is ~76–80 km³/yr (vs ~64 in HIGH); DACCS water is ~15 km³/yr by 2050 under HIGH and avoided in MODERATE/LOW. Fertilizer demand for bioenergy crops is higher under HIGH due to greater bioenergy land. Across 2025–2050, LOW shows the largest percent increases in bioenergy cropland in several countries (e.g., South Korea >3000%), reflecting more bioenergy use without CCS; other agro-land types (crops, grass, shrubs, pasture) decline across scenarios, with least-severe reductions under MODERATE.
• Air pollution co-benefits are higher when CDR reliance is minimized due to faster phase-down of fossil use and inefficient practices.

The results demonstrate that expecting multi-gigatonne CDR enables continued fossil fuel use, raises residual emissions, and slows sectoral decarbonization, thereby jeopardizing timely domestic net-zero attainment and elevating energy–land–water trade-offs. Modeling scenarios that explicitly cap CDR while holding emissions reductions constant shows that lower CDR reliance accelerates electrification, renewables uptake, and efficiency, yielding lower positive emissions and greater air quality co-benefits. However, some CDR remains necessary to counterbalance hard-to-abate residuals by mid-century. Policy relevance is high: separating CDR and emissions reduction targets prevents substitution and moral hazard, aligns with equity and development goals, and reduces the risk that unproven large-scale CDR fails to materialize. Countries should emphasize rapid decarbonization now and deploy CDR as a complementary tool, choosing approaches suited to local resource, infrastructure, and cost contexts, while being mindful of land and water constraints.

Overreliance on CDR in Asia risks carbon lock-in, delayed transitions, increased residual emissions, and greater stress on land, water, and fertilizer systems. Moderate-to-low reliance coupled with ambitious decarbonization accelerates clean energy transitions, reduces positive emissions, brings air pollutant co-benefits, and makes domestic net zero by 2050 more attainable without resorting to foreign CDR purchases. Policymakers should set separate targets for emissions reductions and CDR, prioritize proven mitigation options, and scale CDR realistically as a complement for residual emissions. Future research should refine regional CDR suitability assessments, improve representation of novel CDR technologies in IAMs (including costs, resource use, and constraints), evaluate equity-based CDR allocation, and explore economic and social impacts of accelerated transitions under limited CDR reliance.

The study focuses on Asia under a single socioeconomic pathway (SSP2) and uses stylized scenarios with explicit caps on CDR availability and deployment timing. Novel CDR technologies (e.g., DACCS, ERW, DORCS, biochar) are represented with assumptions and remain characterized by cost and scalability uncertainties. Some results (e.g., island regions) are not shown in maps. Sensitivity analyses are provided in supplementary materials, but real-world policy, technology, and equity constraints may differ from modeled assumptions.