Sector-specific and carbon removal targets could limit adverse impacts of climate change and promote sustainability

doi:10.21203/rs.3.rs-5045485/v1

This study explores a new approach in modeling explicit targets for decarbonization of the electricity and transport sectors combined with separate targets for carbon dioxide removal (CDR) based on the current plans and strategies put forward or expected by countries. Additionally, we examine an equitable "fair share" scenario that aligns sectoral decarbonization timelines and CDR liabilities with the respective capabilities of countries. In this "capability" burden-sharing principle, developed countries with the financial means to support their climate change mitigation efforts undertake faster energy transition while developing countries with lower incomes are allowed an extended timeline for decarbonization and are exempted from excessive CDR obligations. Here, we modify a technology-rich multi-sector model in a manner where explicit sectoral emission reduction and CDR targets can be modeled. Our analysis reveals that adopting this sector-specific strategy shows a potential reduction in residual emissions by up to 35%, and a 35-45% decrease in carbon removal requirement. Furthermore, sector-specific decarbonization and carbon removal targets not only help mitigate the adverse impacts of climate change but also promote sustainability by supporting food security and reducing the global demand for water, land, and fertilizer necessary for energy production and negative emissions.

Scientific community and society/Energy and society

Earth and environmental sciences/Climate sciences/Climate change

As global carbon dioxide (CO₂) emissions persistently increase, the remaining carbon budget (RCB)—the total net anthropogenic CO₂ that can still be emitted while limiting global warming to a specific target, such as 1.5°C or 2°C above pre-industrial levels—continues to diminish ^1,2. Based on current emissions, the remaining carbon budget (RCB) to limit global warming to 1.5°C (likelihood of 33-67%) could be entirely exhausted within the next 4-7 years ^1,3. The RCB can be increased or decreased depending on how deeply the world reduces emissions of both CO₂ and non-CO₂ greenhouse gases (GHGs) ⁴. Urgent and deep decarbonization across all sectors is, therefore, imperative to extend the lifespan of the RCB.

Most existing scenarios from integrated assessment models (IAMs) are based on 'backcasting,' ⁵ which involves identifying pathways to meet predefined climate targets, typically using an economy-wide carbon price ^6–11. However, real-world climate policies involve a complex mix of instruments with varying implicit carbon prices across sectors ⁵, which may not align with the most cost-effective pathways suggested by backcast scenarios ^12–14. While an economy-wide approach is cost-effective in theory, it fails to directly address the specific challenges faced by individual economic sectors in terms of technology and decarbonization^15–26. Considering the speed at which the RCB is being depleted, climate policy is needed to reduce emissions now, sector by sector, if global and domestic climate targets consistent with 1.5^oC are to be reached ^21,27. By setting explicit targets for emissions reductions in key sectors, rather than applying a blanket economy-wide policy, policymakers can potentially drive a more rapid and targeted decarbonization process ²¹. Such sector-specific targets include US’ Regional Greenhouse Gas Initiative (RGGI) ²⁸, US and Canada’s carbon-free electricity by 2035 ^29,30, Korea’s carbon neutrality plan ³¹, and the European Green Deal ³²

Existing scenarios indicate that allowing a moderate level of residual emissions in certain sectors, compensated by removals in other sectors, may be more economically viable than striving for hard zero emissions across all sectors ^2,33. Notably, only 5% of the scenarios assessed in Intergovernmental Panel on Climate Change's (IPCC) Sixth Assessment Report (AR6) achieve global net-zero emissions with residual emissions below 5 GtCO₂/yr. The vast majority of scenarios reach similar net-zero targets by permitting an average of 11 GtCO₂/yr of residual emissions ³⁴, which would necessitate balancing these emissions by carbon dioxide removal (CDR) technologies - technologies yet unproven at scale ^2,35–37.

The massive scale of CDR deployment projected by many IAM scenarios, reaching over 10 GtCO₂/yr by mid-century, faces huge uncertainties in terms of technological scale-up, costs, environmental impacts, and availability of geological CO₂ storage capacity ^36,38–40. Furthermore, existing literature shows that future pathways that fail to separate emission reduction and removal efforts put the world on a path of adverse climate change impacts through continued fossil fuel consumption. Such pathways also increase land, water, and fertilizer demands for energy provision and negative emissions, presenting significant consequences for global sustainability ^41–45. There are thus urgent calls to detach CDR and decarbonization targets as a way of ensuring that negative emissions can scale up without undermining significant emission reductions ^46,47. While few countries like South Korea and United Arab Emirates have responded to these calls, many net-zero pledges made by countries including those from major emitters such as the US, China, EU and India do not explicitly separate emission reduction and removal targets ⁴⁸.

This study explores a new approach of modeling separate, explicit targets for decarbonization of the electricity and transport sectors based on the current plans and strategies put forward by countries, combined with separate targets for limiting total CDR deployment to more modest and sustainable levels. We base the sector targets on the emission reduction goals outlined in countries' long-term strategies (LTS) submitted to the United Nations Framework Convention on Climate Change (UNFCCC). For the CDR targets, we model deployment levels aligned with the quantified amount proposed in countries' LTS.

Importantly, any sector-specific mitigation targets and CDR requirements must be implemented through an equity lens. Developed countries with greater historical responsibility for emissions and more resources should be expected to pursue more rapid energy transitions and shoulder a larger burden of the CDR deployment needed to compensate for residual emissions ^49–52. In contrast, low-income countries/regions may need more time to decarbonize critical sectors like electricity and transport as well as bring their plans for future CDR in line with sustainable development priorities. Hence, we also explore an equitable "fair share" scenario that aligns sectoral decarbonization timelines and CDR responsibilities with countries' respective capabilities. Under this "capability" burden-sharing principle, developed nations, equipped with the financial resources to support their climate change mitigation efforts, are expected to accelerate energy transitions in the electricity and transport sectors—two sectors currently accounting for approximately 60% of global CO₂ emissions. In contrast, developing countries with lower incomes are granted an extended transition period to decarbonize these sectors. Similarly, low-income countries or regions that have not been historically responsible for the global climate crisis are exempted from excessive CDR obligations (See Methods and Table 1). Table 1 provides a general summary of the scenarios explored in this study.

Table 1 Scenario description

Scenario	Description	Separate CDR target	Countries/regions considered for sector-specific mitigation efforts	Sector-specific mitigation efforts	Explicit targets for electricity and transport	Explicit target for CDR
Conventional (CONV)	Global 1.5^oC under one uniform carbon price pathway where total GHG emissions peak by 2025. Total net zero GHG is expected by the 2060s	No. Unlimited capacity	None	None	Endogenously determined	Endogenously determined
Sectoral (SECT)	Follows CONV but with separate transport and electricity targets	Yes. Limited to < 1 GtCO₂/yr of novel CDR and less than 7 GtCO₂/yr of gross CDR by 2050	Major emitters	Only major emitters follow their explicitly announced or projected reduction targets for the transport and electricity sectors, as stated in their official LTS or new GHG target communications	-US: 100% decarbonized electricity by 2035 (Publicly announced). 75-100% decarbonized transport by 2050 relative to 2005 (projection in LTS) - China: Net zero electricity before 2050 and zero carbon emission in the transport sector by 2050 (projection in LTS. See Method) - EU: 100% decarbonized electricity before 2035 and 80% decarbonized transport by 2040 relative to 2015 (projection in new EU 2040 GHG target communication)	Per the CDR targets proposed by countries in their LTS submissions as of September 2022, novel CDR grows by factor of 300 from now to 2050 ³⁶. There is thus a gap between actual CDR required for 1.5 ^oC and what countries have proposed. In a high renewables pathway, global novel CDR has to grow by a factor of 450 by 2050 compared to 1700-folds in a high CDR pathway ³⁶. Here, we explicitly model CDR target based on the high renewable pathway
Sector-ambitious (SECT-AMB)	Same as information in SECT	Same as information in SECT	All countries	All countries/regions follow individual targets for their respective electricity and transport sectors based on the mitigation efforts of the major emitters, as assumed from the "SECT" scenario	-For the electricity sector of each region, a 95% emission reduction by 2030 and 100% reduction by 2050 are pursued relative to 2020 levels. -For the transport sector of each region, a 40% emission reduction by 2030 and 100% reduction by 2050 are pursued relative to 2020 levels. (See Method)	Same as information in SECT
Sector-fair (SECT-FAIR)	Same as information in SECT	Same as information in SECT	All countries	Following electricity and transport sector decarbonization similar to that of major emitters could overburden other emerging economies. Each country or region follows a fair and equitable mitigation effort to decarbonize their respective electricity and transport sectors, consistent with limiting global warming to 1.5°C.	Here, the choice of when countries should set explicit targets for zero carbon emissions in the electricity and transport sectors is based on burden sharing principle (capability principle ^49,50). Countries with a GDP (at purchasing power parity) per capita greater than the global average are mandated to set 100% decarbonization targets for their electricity and transport sectors in the near-term. The remaining countries set their targets for a much later date, extending beyond mid-century. See Table 2	Same as information in SECT. However, due to financial burden CDR could pose on emerging economies, the deployment of novel CDR is solely limited to countries with a GDP (at purchasing power parity) per capita greater than the global average (based on capability burden sharing principle) For removals by LULUCF, the deployment ambition of countries with GDP per capita below global average is set 50% less than the ambition of countries with GDP greater than global average

Table 2 Description of sector decarbonization pathways per scenario

Region	Electricity	Transport
	CONV (decarbonization pathway)
All countries and regions	Endogenous	Endogenous

	SECT (based on public announcements or modelled projections in region’s official LTS submission or new GHG target communication)
USA	100% decarbonized by 2035	75-100% decarbonized by 2050 relative to 2005
China	100% decarbonized by 2050	100% decarbonized by 2050
EU-15	100% decarbonized by 2035	80% decarbonized by 2040 relative to 2015
EU-12	100% decarbonized by 2035	80% decarbonized by 2040 relative to 2015
Rest of the world	Endogenous	Endogenous

	SECT-AMB (based on major emitters’ combined ambitions from SECT)
All countries and regions	Each country or region achieves a 95% emission reduction by 2030 relative to their 2020 levels and 100% reduction by 2050	Each country or region achieves a 40% emission reduction by 2030 relative to their 2020 levels and 100% reduction by 2050

	SECT-FAIR (input from climate analytics ⁵³ and re-distributed according to capability burden-sharing principle). Data here shows the modeled year when each country/region achieves zero emissions sector
Middle East	2045	2065
European_Non_EU	2040	2070
Southeast Asia	2040	2070
Central Asia	2040	2060
Africa_Northern	2040	2065
Africa _Western	2040	2055
South Asia	2040	2065
South America_Southern	2040	2050
South America_Northern	2040	2050
European_Eastern	2040	2065
European Free Trade Association	2025	2045
Central America and the Caribbean	2040	2050
Australia_NZ	2040	2050
Africa_Eastern	2025	2050
Africa_Southern	2030	2050
China	2030	2050
India	2040	2060
Indonesia	2040	2060
Japan	2040	2055
Pakistan	2040	2065
South Korea	2040	2050
Argentina	2040	2050
Brazil	2030	2050
Colombia	2035	2065
Mexico	2040	2055
South Africa	2040	2060
Canada	2030	2050
USA	2035	2045
EU-15	2040	2050
EU-12	2040	2050
Russia	2040	2050

Our analysis indicates that adopting a targeted sectoral strategy could substantially accelerate the decarbonization process relative to the conventional pathway, yielding key advantages such as: a 35-45% reduction in the amount of negative emissions deployment required for the climate target and a 0.17°C lower peak in global mean temperature. Furthermore, pursuing the sectoral pathways could extend the time to exhaust the RCB by at least 7 years compared to the time of exhaustion under the conventional economy-wide scenario (Table 3). Moreover, the global adoption of ambitious explicit targets for decarbonizing the electricity and transport sectors, aligned with the ambition levels demonstrated by major emitting economies (SECT-AMB scenario), could provide additional substantial climate benefits compared to scenarios where such ambitions are only carried out by major emitters (SECT scenario). Specifically, this broader implementation could further reduce the negative emissions requirement over the century by approximately 10-20% and fossil fuel and industry CO₂ emissions by close to 10%. Incorporating fair burden-sharing principles further reduces fossil fuel and industry emissions while easing the CDR burden on low-income regions with lower historical responsibility and financial capability to combat climate change mitigation.

Table 3 Summary of key findings according to scenario

Indicator	CONV	SECT	SECT-AMB	SECT-FAIR
Cumulative residual fossil fuel and industry CO₂ emissions from 2020 to 2100 (GtCO₂)	1340	953	892	862
Cumulative total net CO₂ emissions from 2020 to 2050 (GtCO₂) ^a	838	550	544	546
Year to exhaust RCB ^b	Before 2032	Before 2039	Before 2040	Before 2039
Peak and 2100 temperature (^oC)	1.91 and 1.49	1.74 and 1.40	1.73 and 1.40	1.73 and 1.39
Cumulative CDR from 2020 to 2100 (GtCO₂)	993	654	582	539
Cumulative renewables and nuclear in primary energy supply from 2020 to 2100 (PWh)	6982	7950	8357	8317
Cumulative electricity and hydrogen in final energy consumption from 2020 to 2100 (PWh)	7222	7525	7713	7721

RCB: Remaining carbon budget.

^a The 2020-2022 values were harmonized to historical emissions

^b RCB here is based on IPCC’s AR6 ² from 2020 onwards, which is 500 GtCO₂. To estimate the time left for each scenario to completely exhaust the RCB, we yearly interpolated the scenarios to report net emissions annually. Then, the 2020-2022 values were harmonized to historical emissions, after which the cumulative sum of the emissions was calculated to obtain the year when each scenario exceeds the RCB.

Remaining carbon budget, peak warming, and net-negative emissions

This study examines scenarios for limiting global temperature rise to 1.5°C above pre-industrial levels by 2100. The scenarios differ in their pathways and the extent of overshooting the RCB of 500 GtCO₂ for 1.5°C ². The conventional economy-wide pricing scenario results in a significant overshoot, exceeding the RCB from 2020 onwards by 338 GtCO₂, leading to peak warming of 1.91°C by 2055. In contrast, scenarios with explicit sectoral targets and CDR limits (SECT, SECT-AMB, SECT-FAIR) have a relatively limited overshoot, and exceed the RCB by less than 50 GtCO₂, peaking at ~1.74°C by 2045 (Table 3).

Higher overshoots require greater CDR deployment ⁵⁴, and CONV demands nearly 1000 Gt of cumulative CDR to return below 1.5°C after ~75 years of overshoot. The SECT and SECT-AMB scenarios require 582-654 Gt of CDR, with a shorter ~55-year overshoot period. The SECT-FAIR, considering equitable regional mitigation efforts for both sector decarbonization and carbon removal, further reduces the negative emissions requirement compared to SECT and SECT-AMB scenarios.

Emissions, regional CDR distribution and net zero timing

Sector-specific decarbonization and carbon removal targets accelerate the reduction of residual CO₂ emissions compared to the conventional economy-wide scenario (Fig. 1). For example, in the Global North, particularly in North America and Europe, cumulative transport residual emissions are expected to reach about 69-71 GtCO₂ under the conventional (CONV) scenario, compared to 27-42 GtCO₂ under sector-specific scenarios. This trend is consistent for residual emissions from the electricity sector and across other regions. However, in the Global South, particularly in Africa and Asia, compared to SECT-AMB, pursuing equitable sector-specific decarbonization and carbon removal (SECT-FAIR) may slow the reduction of transport and electricity emissions, as these regions require more time to phase out fossil fuel consumption in these sectors.

Additionally, without explicitly targeting decarbonization in the building and industry sectors, residual emissions in these areas remain consistent with those from the conventional scenarios, even when there are varying degrees of reliance on CDR. This highlights the importance of sector-by-sector decarbonization, ensuring no sector is overlooked.

Fig. 2 shows different pathways to net zero CO₂ emissions by mid-century. All scenarios achieve net-zero CO₂ emissions between 2050 and 2055, with sectoral scenarios reaching this milestone a few years earlier than the conventional one (Fig. 2). By 2050, the conventional scenario will be about 6 Gt/yr away from net zero, while sectoral scenarios will be less than 1 Gt away. The conventional pathway reduces residual CO₂ emissions from fossil fuels and industry by 57% from 2015 to 2050 (Fig. 2a). The electricity sector in the conventional scenario sees an 85% reduction, while the transport sector sees a 35% reduction by 2050. LULUCF emissions must decrease from 3.6 GtCO₂/yr in 2015 to -4.3 GtCO₂/yr by 2050 (Fig. 2a).

The SECT scenario (according to modeling design) ensures an additional 15% and 45% decarbonization in electricity and transport, respectively, compared to the conventional scenario. The SECT pathway reduces reliance on “CO₂ removal” by 4 Gt/yr by 2050, prioritizing non-CDR measures like electrification, energy efficiency, and hydrogen. LULUCF removals need to increase by 1 Gt/yr to compensate for limited novel removal approaches (Fig. 2b). The SECT-FAIR scenario, with explicit and equitable targets, achieves an additional 15% decarbonization in transport compared to SECT, but slightly slows down decarbonization in other sectors like buildings, industry, and agriculture. It also avoids 0.7 Gt/yr of LULUCF removals compared to SECT (Fig. 2c). In Fig. 2d, we see that the SECT-AMB scenario, the most ambitious pathway, shows similar decarbonization levels across sectors as SECT-FAIR, highlighting the need for equitable climate action.

All pathways show increased emissions from gas and hydrogen supply due to higher energy demands for zero and low-carbon carriers, with SECT-AMB resulting in the highest emissions growth from gas and hydrogen supply to decarbonize transport by 2050. Detailed discussions in Supplementary Discussion 1.

CDR deployment varies greatly across 1.5°C scenarios, with gross CDR under CONV reaching 10 Gt/yr by 2050, double that of sectoral scenarios. Under CONV, the US, China, and EU contribute 50% of global novel CDR by mid-century, while emerging economies in Africa and Asia (excluding China) contribute 25%. SECT-AMB sees major emitters contributing 45%, while emerging economies' contributions remain around 25% (Fig. 3a). SECT-FAIR shifts 80% of the novel CDR burden to major emitters, with emerging economies focusing on LULUCF negative emissions.

LULUCF removals show significant variation across scenarios (Fig. 3b). Sectoral scenarios rely more on LULUCF removals than CONV due to their lower dependence on novel CDR technologies. An ambitious pathway with all countries setting explicit sectoral and CDR targets leads to the highest LULUCF utilization throughout the century. By 2050 (across all scenarios), the US, EU, and China contribute 10-15% of total LULUCF deployment, while emerging economies in Africa and Asia (excluding China) contribute 30-35%. This suggests that the Global North (including China in this case) may find novel CDR technologies more economically viable, while the Global South leans towards LULUCF removals. Detailed discussions in Supplementary Discussion 2.

Fig. 3a and 3b illustrate the distribution of CDR by region in 2050, while Fig. 4 presents the cumulative gross CDR (both conventional and novel) from 2020 to 2100 by ten major emitters. Fig. 4 highlights the importance of sector-specific targets on a global scale when comparing cumulative CDR under SECT and SECT-AMB scenarios. Although both scenario groups share the same carbon removal upper limit by mid-century (see Table 1 and Methods), the zero (or net zero) transport and electricity targets under SECT apply only to three major emitters (US, China, and EU-27), whereas SECT-AMB targets are applied to all countries. Consequently, worldwide decarbonization beyond the major emitters results in a more significant reduction in residual emissions, thereby decreasing the reliance on negative emissions throughout the century.

For major emitters in the Global North, as well as China, our results indicate a higher CDR obligation under SECT-FAIR compared to the other two sectoral scenarios. This shift can be attributed to the exemption of countries with limited financial capabilities from excessive CDR responsibilities, in line with climate justice principles, which transfers a greater portion of the removal burden to these major emitters.

India's situation is particularly noteworthy, as it records a cumulative net positive (negative sign in Fig. 4) under SECT-FAIR. As a Global South and developing country, India is not obligated to pursue novel CDR under this scenario, and its role in land sector mitigation (i.e., conventional CDR) is limited (see Table 1 and Methods). Consequently, the cumulative gross emissions from India's land-use sector (deforestation) exceed its gross removals (afforestation/reforestation), leading to a cumulative net positive emissions profile over the century.

The analysis indicates that setting explicit sectoral targets for electricity and transport decarbonization, combined with constrained CDR deployment, leads to faster near-term CO₂ emissions reductions compared to conventional economy-wide carbon pricing. From 2020-2050, major emitters like the US and China achieve 95-110% net CO₂ reductions under sectoral scenarios, versus 80-85% under CONV, which relies heavily on future large-scale CDR.

Due to cost-effectiveness under CONV, several regions may prefer future CDR over rapid near-term decarbonization, delaying their domestic net-zero CO₂ emissions beyond this century consistent with findings from Ampah et al. ⁴⁵. In contrast, SECT-AMB enables earlier domestic net-zero due to rapid net emissions reduction and limited reliance on negative emissions. For example, EU-15 reaches net-zero CO₂ by 2095 under CONV, but by 2050-2055 under sectoral scenarios. EU-12 and Indonesia achieve net-zero 10 and 30 years earlier under sectoral scenarios, respectively. South Korea does not reach net-zero in the 21st century under CONV but could by 2065 under SECT-AMB/FAIR. However, regions with high carbon lock-in like India, Pakistan, and South Africa may not attain net-zero CO₂ this century, regardless of the pathway (Fig. 3c). Detailed discussions in Supplementary Discussion 3.

Extended Data Fig. 1 provides a comprehensive comparison of our alternative 1.5°C scenarios with those explored in the IPCC's AR6 in terms of temperature change, effective forcing, positive and net emissions, carbon removal, and geologic carbon storage. A major divergence emerges in novel CDR deployment and geological carbon sequestration under CONV. In the conventional pathway, novel CDR reaches approximately 18 Gt/yr by 2100, comprising 9 Gt/yr from BECCS, 7 Gt/yr from DACCS, and 2 Gt/yr from ERW. In contrast, the sectoral scenarios with capped negative emissions and rapid sectoral decarbonization (electricity and transport) exhibit moderate novel CDR reliance. By 2100, BECCS deployment ranges from 3.5-4.5 Gt/yr, DACCS from 3.5-4.5 Gt/yr, and ERW from 0.8-1.3 Gt/yr across these scenarios.

Impact on primary and final energy use

The sectoral scenarios lead to a substantial reduction in coal demand, mitigating its consumption by up to 85% between 2020 and 2050. This contrasts sharply with the conventional carbon pricing pathway, which only achieves a 70% decrease over the same period. The uniform economy-wide carbon pricing approach adopted in CONV alongside multi-gigatonnes expectations of CDR may not provide sufficient incentives to drive down consumption of fossil fuels in the near term, thereby prolonging the lifetimes of existing infrastructure (Extended Data Fig. 2a). Compared to the CONV scenario, the sectoral scenarios show a more rapid phase-down of fossil fuels in key regions such as North America, Asia, and the European Union, accelerating the transition by an additional 30%, 35%, and 25%, respectively, during the 2020-2050 timeframe (Extended Data Fig 2b). Concurrently, while fossil fuel consumption for primary energy needs in Africa would rise by 35% under the CONV scenario, the sectoral scenarios project a 10-40% reduction in fossil fuel consumption across the African continent between 2020 to 2050.

In 1.5°C pathways, fossil fuel consumption is expected to decrease while electrification (both direct and indirect) increases significantly compared to a reference pathway (No Policy) consistent with approximately 3.5°C. However, the reduction in fossil fuel use and the increase in electrification can be further accelerated under sector-specific decarbonization with limited reliance on carbon removal, as opposed to blanket or economy-wide conventional pathways, as shown in Fig. 5a and 5b. Among all pathways, pursuing equitable decarbonization and removal (SECT-FAIR) or ambitious decarbonization and removal (SECT-AMB) leads to the most rapid phase-down of fossil fuel consumption and the most significant upscaling of electrification and hydrogen use in end-use sectors across various regions.

Pursuing explicit sectoral and separate CDR targets promotes energy efficiency in end-use sectors. Electricity, due to its high exergy, enables more usable work than equivalent amounts of other fuels ⁵⁵, leading to lower total energy demand under sectoral scenarios, especially before mid-century. Between 2020 and 2050, sectoral scenarios provide an additional 10% phase-down in coal and a 40% rise in electrification compared to the conventional pathway (Extended Data Fig. 3). Sectoral scenarios accelerate coal consumption reduction in North America, Asia, and the EU by an additional 25-30% during this period (Extended Data Fig. 4).

By 2050, under the conventional pathway, carbon-based sources, including biomass and fossil fuels, account for 70% of total primary energy consumption, which reduces to 50-55% when explicit targets are set for electricity and transport alongside separate CDR targets. In an ambitious sectoral pathway (SECT-AMB), renewables and nuclear combined could reach 50% of the energy mix by 2050, compared to less than 30% under CONV (Fig. 6). Electricity decarbonization is central to any 1.5°C pathway. Thus, despite higher electrification rates under SECT-AMB and other sectoral pathways, the increase is less than 20% over CONV. SECT-AMB achieves a 40% reduction in transport energy demand compared to CONV, due to rapid electricity/hydrogen deployment and phase-out of fossil fuels in transport. By 2050, lower reliance on CDR and rapid sector decarbonization reduces energy demand for carbon removal. Without explicit targets for industry and buildings, CONV and SECT-AMB result in similar energy demands in these sectors. By 2050, sectoral scenarios achieve an additional 10-17 EJ/yr of hydrogen consumption, primarily for deep-decarbonizing transport. The most significant reduction in energy carriers between CONV and sectoral scenarios occurs in refined liquids (oil refining, biomass liquids, coal-to-liquids, and gas-to-liquids), with a 50% reduction in demand under SECT-AMB compared to CONV. Detailed discussions in Supplementary Discussion 4.

Extended Data Fig. 5 provides a comparison of our 1.5°C scenarios with those explored in the IPCC's AR6, in relation to energy consumption and marginal abatement cost of carbon. The results reveal that due to the delayed implementation of deep near-term mitigation under the conventional economy-wide scenario, its carbon prices during the latter half of the century increases beyond the marginal cost under the sectoral scenarios. This phenomenon can be attributed to the necessity for relatively rapid and deep decarbonization to occur under the CONV scenario during the second half of the century, in order to compensate for the earlier delay. Consequently, this scenario undergoes a swift transition from relatively lower marginal abatement costs until 2060 (at $564/tCO₂ compared to $604-650/tCO₂under the sectoral scenarios). Conversely, the earlier realization of deep decarbonization under the sectoral scenarios presents an opportunity to decelerate the pace of mitigation efforts during the second half of the century (relative to the CONV scenario). This, in turn, leads to a transition from relatively higher near-term carbon prices to comparatively lower prices later in the century from 2065 onwards (CONV’s carbon price in 2100 reaches $985/tCO₂ compared to $626-695/tCO₂ under the sectoral scenarios).

Impact on water, land, and fertilizer demand

With greater reliance on CDR and a slower transition to non-biomass renewable energy sources under the CONV scenario, negative emissions and energy from biomass are expected to remain elevated. This necessitates an expansion in the cultivation of bioenergy crops and the associated use of fertilizer and water (Fig. 7). Notably, in the CONV scenario, regions such as the US, China, and Mexico exhibit significantly higher fertilizer and water demands for bioenergy crop cultivation compared to the sectoral scenarios. For instance, under CONV, cumulative fertilizer and water demands for bioenergy crops reach approximately 300 MtN and 3000 km³, respectively, compared to around 200 MtN and 2000 km³ under SECT-AMB. Consequently, the CONV scenario poses greater risks related to unsustainable fertilizer use and global water scarcity.

We also observe that land allocation for bioenergy crops is generally expected to be higher under the conventional (CONV) scenario compared to the sectoral scenarios. Pursuing a more ambitious sectoral decarbonization globally, with limited reliance on CDR (SECT-AMB), results in the most sustainable use of land for bioenergy crop cultivation among all scenarios (Fig. 8a). In regions such as Africa, Asia, and South America—typically in the Global South—adopting sector-specific decarbonization and equitable carbon removal strategies (SECT-FAIR) provides the best approach for ensuring food security, as land allocation for food in these regions remains relatively higher compared to other scenarios (Fig. 8b). Additionally, the limited reliance on CDR, particularly novel types, under the sectoral scenarios leads to increased land use for afforestation and reforestation, thereby expanding forest areas compared to the CONV scenario, where more novel CDR deployment is expected (Fig. 8c). Conversely, other agrolands, including grass, shrubs, pasture, and arable land, are likely to decrease under CONV as bioenergy cropland expands, compared to the sectoral scenarios (Fig. 8d).

In recent years, there are growing concerns within the scientific community for modelers and policy-makers to consider decarbonization on sector-by-sector basis and explicit separate targets for carbon removal ^21,46,47,56. In this study, we respond to these calls by modeling explicit targets for decarbonizing the electricity and transport sectors coupled with separate CDR deployment trajectories aligned with countries’ LTS submissions or new GHG target communications. The findings demonstrate that this sectoral approach, when coupled with moderate CDR, can yield significant climate benefits compared to conventional economy-wide carbon pricing pathways. Notably, it reduces the required negative emissions deployment over the century by 35-45%, lowers peak warming by 0.17°C, and could extend the time remaining before we exhaust the RCB by at least 7 years. Crucially, we show that that widespread adoption of such explicit sectoral targets by all countries, not just major emitters, could further amplify these advantages, reducing negative emissions needs and lower GHG emissions.

Recent studies highlight the need for all countries/regions to ratchet up their climate ambitions to keep warming below 1.5°C ^57,58. Under a conventional, economy-wide pathway, several regions may find it more economically advantageous to rely heavily on CDR mitigation solutions rather than rapidly reducing emissions. Such an approach could potentially delay the attainment of domestic net-zero CO₂ emissions of several countries beyond this century. However, an ambitious sectoral pathway, coupled with separate CDR targets, would incentivize countries to pursue rapid reductions in net emissions and limit their reliance on negative emissions technologies. This alternative approach would enable several countries to achieve domestic net-zero CO₂ emissions earlier than anticipated under conventional pathways. A more equitable approach to setting targets for sector decarbonization and carbon removal may lead to reduced CDR and emission reduction burden on emerging economies. Under such an equitable pathway, the novel CDR obligations of the US, China, and the EU by mid-century could roughly double compared to conventional and ambitious sectoral scenarios, while Africa and Asia’s (excluding China) obligations reduce from 25% under conventional and ambitious sectoral scenarios to less than 3% under an equitable pathway.

Moreover, these targeted strategies contribute to sustainability by addressing the resource demands associated with energy production and carbon removal. For example, excessive reliance carbon removal strategies under economy-wide scenarios often require extensive land use for bioenergy crops, which can lead to competition with food production and increased pressure on water and fertilizer resources. In contrast, sector-specific decarbonization and carbon removal targets can be designed to minimize these trade-offs. By promoting more sustainable land use practices, these approaches help to protect food security, particularly in vulnerable regions like Africa and Asia, where land is a critical resource for both agriculture and biodiversity. Additionally, sector-specific strategies can lead to a more efficient use of water and fertilizers. As bioenergy crops require significant inputs of both, a conventional approach that heavily relies on these crops for carbon removal can exacerbate global water scarcity and environmental degradation from fertilizer runoff. By limiting reliance on such resource-intensive methods and focusing on decarbonization within specific sectors, these strategies can reduce the overall demand for these resources, thereby contributing to the sustainability of the global water and food systems.

In future LTS submissions, if countries were to set explicit sector emission reduction targets and quantitatively communicate their planned CDR deployment, there could be profound implications for energy consumption. Such ambitious sectoral and moderate CDR targets would drive a substantial reduction in global fossil fuel demand by 2050 and necessitate a significant deployment of clean energy. Beyond CO₂ emission reduction targets in energy sectors, upcoming LTS submissions from countries must carefully evaluate targeted technology adoption and behavioral changes that could significantly mitigate non-CO₂ GHG emissions. Key areas to consider include efficiency improvements ^2,59, lifestyle shifts such as dietary transitions towards plant-based diets ^2,60,61, reduction of food waste at farm and household levels ⁶², as well as improved crop fertilization and paddy rice cultivation practices ³⁴.

Moving forward, our work can be enhanced by quantitatively modeling behavioral changes aimed at delivering fully decarbonized electricity and transport sectors under equity and other burden-sharing principles. While we have provided vital insights to address our initial research questions, further studies that incorporate a diverse ensemble of IAMs could further enhance the robustness of our findings and provide additional insights into co-benefits under such ambitious pathways, such as employment, energy security and universal energy access, and improved urban livability. Future research could also expand beyond the transport and electricity sectors to consider sector-specific targets for buildings and energy-intensive industrial sub-sectors, either in addition to or as separate targets from those for transport and electricity.

The objectives of this study are achieved using a modified version of Global Change Analysis Model (GCAM-TJU), one of the most widely used integrated assessment models. GCAM operates by converting primary energy resources into secondary energy carriers through various energy transformation sectors. Market shares among competing technologies within these sectors are allocated based on either relative cost or absolute cost logits, influenced by technology costs, efficiency, and fuel prices ⁶³. Key inputs determining the cost of a technology include non-energy costs—covering capital, construction, operation, and maintenance expenses—and the efficiency of energy transformation, where more efficient technologies use less fuel per unit of output. Fuel prices, another critical parameter, are determined endogenously within each modeling period, reflecting changes in supply, demand, and resource depletion ^64,65. GCAM achieves market equilibrium by simulating decision-making processes of representative agents across multiple sectors (e.g., regional electricity, refining, land use). These agents base their resource allocation on costs, prices, and other relevant factors, interacting through markets for physical goods (like electricity and agricultural commodities) and services (such as emissions permits). The model iteratively adjusts prices to balance supply and demand across all commodities, including fossil fuels and emissions permits, thus ensuring market equilibrium in each period ⁶⁶. Emission calculations within GCAM are performed by associating CO₂ emissions with the fuel consumption of each technology, based on global average emission coefficients (e.g., CO₂ per gigajoule) for coal, oil, and natural gas. Additionally, emissions from agriculture and land use changes are calculated based on the extent of these changes, the carbon density of ecosystems, and regional growth profiles ⁵⁷. Hector v.2.5.0 is the default climate model within the version of GCAM used in this study. The global historical trends of surface temperature, atmospheric CO₂, and radiative forcing are reproduced by Hector ⁵⁷. Additional details of the model’s land, water, and fertilizer modules are described in detail in the Supplementary Information.

Updates to GCAM

In this study, we have adopted a distinct approach in modelling emission reduction and removal targets. Our goal is to model explicit CO₂ emission reduction targets in the transport and electricity sectors, coupled with separate CDR targets based on current plans announced or projected by countries in their official LTS submissions or new GHG target communications. To achieve this objective, we have utilized a modified version of GCAM version 6.0, GCAM-TJU 6.0 which has the capability to model explicit CO₂ emission reduction targets in different sectors and separate CDR targets.

In the standard and publicly released version of GCAM, the electricity and transport sectors, along with all other sources of CO₂ emissions, are assigned a common "CO2" tag. This approach allows emission reductions across all sectors to be addressed under a least-cost pathway, which may potentially leave significant residual emissions in key sectors unaddressed. In our update, we disentangle the electricity and transport sectors from this common “CO2” tag by creating separate and new tags for these sectors. This approach enables us to achieve specific emission reduction targets in these two particular sectors within a single model run. This is a notable advancement over previous modeling exercises, where researchers relied on reducing emissions in sectors through iterative fuel/technology switching scenarios. Alternatively, previous studies attempt to reduce emissions in sectors by employing a uniform carbon pricing pathway that applies uniformly across all sectors, which often results in large residual emissions in individual sectors.

Furthermore, in the public version of GCAM, once CDR technologies are enabled, the amount of negative emissions deployed is endogenously determined in a cost-effective manner to reach the specified climate target. While this approach may be economically efficient, it could potentially undermine near-term decarbonization efforts by relying heavily on prospective CDR deployment, which may face technological constraints or sustainability concerns. Here, our GCAM-TJU 6.0 allows for the precise setting of limits on novel CDR, ensuring that decarbonization and removal efforts can be pursued simultaneously without the latter undermining the former. This feature addresses concerns about overreliance on prospective CDR deployment and enables the exploration of pathways that balance ambitious sectoral mitigation with moderate CDR strategies.

With the exception of these updates, all other technological, energy, materials and cost assumptions are same as those present in the standard version of the model, and are available in detail in a public GitHub repository ⁶⁵.

Modeling sector decarbonization pathways for CONV, SECT, SECT-AMB, and SECT-FAIR

CONV represents a conventional economy-wide approach that limits warming to 1.5°C, where a uniform carbon price is applied across all sectors of the economy. To achieve this, a constraint is set on GHG emissions. Net GHG emissions peak before 2030 and linearly decline to reach zero by 2060, after which net negative emissions begin and continue until the end of the century to return warming to 1.5°C after a temporal overshoot. Non-CO₂ GHG emissions are converted to CO₂ equivalents using 100-year global warming potentials (GWPs). Importantly, the emission constraint does not include emissions from land-use change. Net emissions from land use are subjected to a carbon tax at a fraction of the carbon price imposed on fossil fuel and industry (FFI) emissions from 2030 to 2100, which increases linearly from about 15% to 100%. This approach not only incentivizes additional emission reductions but also promotes carbon storage through land-use changes, such as afforestation and reforestation ⁶⁷.

Three sectoral scenarios are modeled, following similar modeling assumptions as CONV. One of the two differences between CONV and the sectoral scenarios is that while sectors' emissions are reduced following one market that "holds" the CO₂ emission constraint pathway in CONV, the sectoral scenarios have three separate emission constraint pathways for electricity, transport, and other sources of CO₂emissions.

Under the SECT scenario, a pathway is modeled where only major emitters follow their publicly announced or projected CO₂ emissions reduction targets for their transport and electricity sectors, as explicitly stated in their official LTS or new GHG target communication. Among the major emitters, only the United States has made explicit announcements for electricity sector emission reduction targets in their official LTS. The LTS of the US also includes projected targets for transport emissions ³⁰, while the European Union's new 2040 GHG target communication includes projected targets for transport and electricity emission reductions within the region ⁶⁸. Although mainland China does not have such an announcement or projection in its LTS, in its communication, they include a projected emission reduction target for electricity and transport emissions for Hong Kong, one of its Special Administrative Regions ⁶⁹. Therefore, under the SECT scenario, it is assumed that this target applies to all of China. Consequently, under the SECT scenario, the major emitters considered are the US, EU, and China, and the explicit targets modeled under this scenario are shown in Table 2.

Most countries have yet to include explicit emission reduction targets for their electricity and transport sectors in their LTS. This raises the question: in a 1.5^oC pathway, what would happen to the time to exhaust the RCB, peak warming, residual emissions, and CDR requirement if all countries followed the assumptions from major emitters regarding their announced (or projected) explicit emission reduction targets for the electricity and transport sectors? The SECT-AMB scenario is designed to explore this premise. Under SECT-AMB, all countries follow the level of ambition set by major emitters, assuming they will announce similar targets for their electricity and transport sectors in future LTS submissions. Following the SECT scenario, it is found that collectively, the electricity emissions of the three major emitters (US, EU, and China) reduce by 95% between 2020-2030 and reach a 100% reduction by 2050. Additionally, their transport emissions reduce by 40% between 2020-2030, 65% between 2020-2040 and reach a 100% reduction by 2050. Consequently, under SECT-AMB, the 2030 electricity emission of each country/region is modeled such that it is a 95% reduction from its 2020 level, and continues to decline linearly to reach zero emissions by 2050. Similarly, each country's 2030 and 2040 transport emissions are modeled to be a 37% and 66% reduction from its 2020 levels, respectively, and continue to decline linearly until reaching zero emissions by 2050.

While the SECT-AMB scenario is ambitious and optimistic, following a similar electricity and transport sector decarbonization path as major emitters could overburden developing countries. Equitable pathways must be explored, even in a future where every country is expected to announce explicit emission reduction targets for their electricity and transport sectors. The SECT-FAIR scenario has been included in this study to account for the capabilities of each country and region in financing their domestic climate change mitigation efforts. Under the SECT-FAIR scenario, each country or region announces when it plans to achieve a fully decarbonized electricity and transport sector, following a fair and equitable mitigation effort consistent with limiting global warming to 1.5°C. In this scenario, input data is collected from Climate Analytics' national pathway explorer, which is based on a fair and equitable distribution of mitigation efforts for all countries (their pathways consider equity and fairness principles in conceptualizing its emissions pathways, but does not explicitly align them with any given equity principle. They operationalize the Paris Agreement's goals, which are meant to be achieved "on the basis of equity" and sustainable development for developing countries). The explorer provides national pathways for countries and sector-specific decarbonization benchmarks derived from global IPCC pathways compatible with the Paris Agreement ⁵³. It provides information on exactly when each country is expected to reach a zero-emission electricity and transport sector in a global 1.5°C pathway. Assumptions are made for GCAM regions that are missing or referred to differently in the data from Climate Analytics. For these regions, the fair mitigation effort of the major emitting country within the region is assumed and applied to the entire region. For example, Nigeria's fair mitigation effort is used to represent African_Western for this study

However, the data from Climate Analytics has an upper and lower bound for each country (for example, they project South Africa to reach a zero-carbon electricity sector between 2036-2040). To use this data, a decision had to be made regarding which bound to use for each country. Thus, countries were divided into two groups: those to be modeled based on the lower bound (decarbonize faster) and those to be modeled based on the upper bound (decarbonize later), based on burden-sharing principles. The chosen bound for a country is based on the capability/ability-to-pay burden-sharing principle, where it is assumed that a country with more resources is more capable of financing its own decarbonization strategies. It is assumed that countries with a GDP per capita below the global average would require more time and resources (financial assistance) to decarbonize their sectors, irrespective of their total GDP and cumulative emissions, compared to countries with a GDP per capita higher than the global average ^49,50. The lower bound is applied when the GDP (at purchasing power parity) per capita is greater than the global average. The upper bound is applied when the GDP (at purchasing power parity) per capita is lower than the global average. See Supplementary Table 1 for more details.

While several burden-sharing principles are available, the main goal of this study is to explore the benefits of sector-specific and separate CDR targets, rather than focusing primarily on equitable pathways. As such, the capability burden-sharing principle was utilized, as it is one of the four core equity categories contemplated by the IPCC ⁵⁰.

Modeling separate CDR target

The CONV scenario in this study aligns with several previous studies, where CDR and decarbonization pathways are not separated. In such scenarios, the amount of CDR deployment is determined endogenously within the model. Since it is often more cost-effective to delay emission cuts and offset emissions later through CDR, the presence of these technologies can inadvertently slow down emission reduction efforts ⁷⁰, leading to pathways where the role of CDR, especially before mid-century, becomes exaggerated ⁹. This is particularly concerning given that these technologies have yet to be proven at scale ³⁵. Consequently, there have been urgent calls within the scientific community to detach CDR and decarbonization targets as a means of ensuring that negative emissions can be scaled up without undermining significant emission reduction efforts ^46,47.

In the sectoral scenarios (SECT and SECT-AMB), we detach CDR and decarbonization pathways, an approach that departs from most existing IAM studies. We set a cap on gross CDR, ensuring that the growth of novel CDR technologies is more realistic and achievable under current technological and scientific knowledge, compared to the existing pathways that project CDR at over 10 GtCO₂/yr by mid-century. This cap is achieved by modeling novel CDR based on the gap between the quantified CDR targets stated in countries' LTS and the least requirement for limiting global warming to 1.5°C. According to the CDR targets proposed by countries in their LTS submissions as of September 2022, novel CDR is expected to grow by a factor of 300 from the present day to 2050 ³⁶. Considering that today's novel CDR deployment is only 0.002 Gt/yr ³⁶, this growth rate would result in a novel CDR of around 0.6 Gt/yr by mid-century, representing a gap compared to what is actually required for achieving the 1.5°C target. Smith et al. ³⁶ show that to bridge this gap, novel CDR must rather grow by a factor of 450 between now and 2050 if a high renewable pathway is followed (leading to a novel CDR of 0.9 Gt/yr), or by a factor of 1700 if a high CDR pathway is followed (leading to a novel CDR of 3.4 Gt/yr). Based on these estimates, we cap novel CDR to not exceed 0.9 Gt/yr by 2050, a significant departure from existing studies where the exact cap on negative emissions is solely at the discretion of the authors ^{41–43,71–73}.

For removals by LULUCF under the CONV, SECT, and SECT-AMB scenarios, all countries have equal ambitions, where their land-use emissions are priced at a fraction of the level as the carbon price on FFI, which increase from 15% in 2030 to 100% in 2100.

Equitable CDR distribution is modeled under the SECT-FAIR scenario, based on the capability/ability-to-pay burden-sharing principle following previous studies ^49,50,74. In this scenario, the expectation of 0.9 Gt/yr of novel CDR deployment by 2050 is shared only among countries with a GDP (PPP) per capita greater than the global average. The remaining countries do not partake in the responsibility of deploying novel CDR at any point during this century. However, all countries participate in removals by LULUCF deployment, with the ambition of low-income regions set to less than 50% lower than that of major economies.

Rationale for limiting sectoral scenarios to electricity and transport

In our analysis, we concentrated exclusively on the transport and power sectors. This decision stemmed from our research methodology, wherein the foundational sectoral scenario (SECT) was formulated based on explicit emission reduction targets for sectors announced or projected in the LTS or new GHG emission target communications of major emitting countries. With the exception of the United States, none of the major emitters' LTS included explicit emission reduction targets for the industry and building sectors. Our findings highlight the necessity for all countries to provide such explicit targets for all economic sectors in their future LTS. Nonetheless, our focused exploration of the electricity and transport sectors in this study offers a meaningful contribution toward the attainment of global climate milestones. The power sector is responsible for approximately 40% of global CO₂ emissions ⁷⁵. Developing strategies to fully decarbonize electricity grids is of paramount importance ^76–78. Currently, the most effective method for reducing emissions from the power sector is the rapid expansion of renewable energy, driven largely by the declining costs of renewable energy technologies ^79–81 and incentive programs ^82–84. However, achieving a completely zero-emission electricity grid that remains reliable continues to pose a significant challenge ^85,86. The transport sector also presents its own set of challenges. Its high dependence on oil and the dispersed nature of its emissions makes it one of the most challenging sectors to decarbonize ^87–89. Unlike some other sectors, the transport sector tends to respond more slowly to policies such as carbon taxes ⁶⁷. Together, the power and transport sectors account for over 60% of global emissions today ⁷⁵. Existing pathways designed to limit global warming to 1.5 °C indicate the need for substantial deployment of CDR technologies in both the power sector (in the form of BECCS) ^2,90 and the transport sector ^41,91. This deployment is necessary to offset the relatively large residual emissions from sectors that are hard to decarbonize, such as heavy-duty vehicles, aviation, and shipping.

Acknowledgements

We are grateful to the National Natural Science Foundation of China for supporting the current study with funding numbers 22461142138 & 52176125 received by H.L. H.M was supported by the National Research Foundation of Korea grant RS-2023-00219466.

Author contributions

J.D.A, H.L, C.J, M.Y, H.A., Y.Y., Y.O., and H.M. conceived and designed the research. J.D.A developed the scenarios, conducted the modeling, and wrote the first draft of the paper. J.F, P.K., and H.M. contributed to the modeling tools. S.A, H.A., B.O., M.D., and X.Z., co-led parts of the assessment and contributed to data analysis. H.L, C.J, Y.Y., M.Y, Y.O., and H.M. supervised the research. J.D.A, C.J, H.L, M.Y, Y.Y., P.K., M.D., B.O., X.Z., S.A., J.F., H.A., D.T.H., Y.O., and H.M. contributed to the writing of the article.

Competing Interest

The authors declare no competing interests.

Code and Data availability

GCAM is an open-source community model available at https://github.com/JGCRI/gcam-core/releases.

The version of GCAM and other input files used in this work will be made available in a public GitHub

repository upon publication.

Forster, P. M. et al. Indicators of Global Climate Change 2022: annual update of large-scale indicators of the state of the climate system and human influence. Earth Syst. Sci. Data 15, 2295–2327 (2023).
IPCC. Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. ([P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, 2022).
Lamboll, R. D. et al. Assessing the size and uncertainty of remaining carbon budgets. Nat. Clim. Change (2023) doi:10.1038/s41558-023-01848-5.
IPCC. Climate Change 2021 – The Physical Science Basis: Working Group I Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. FAQ 5.4, Chapter 5. (Cambridge University Press, 2023). doi:10.1017/9781009157896.
Sognnaes, I. et al. A multi-model analysis of long-term emissions and warming implications of current mitigation efforts. Nat. Clim. Change 11, 1055–1062 (2021).
Fujimori, S. et al. SSP3: AIM implementation of Shared Socioeconomic Pathways. Glob. Environ. Change 42, 268–283 (2017).
Calvin, K. et al. The SSP4: A world of deepening inequality. Glob. Environ. Change 42, 284–296 (2017).
van Vuuren, D. P. et al. Alternative pathways to the 1.5 °C target reduce the need for negative emission technologies. Nat. Clim. Change 8, 391–397 (2018).
Strefler, J. et al. Alternative carbon price trajectories can avoid excessive carbon removal. Nat. Commun. 12, 2264 (2021).
Krey, V. et al. MESSAGEix-GLOBIOM Documentation - 2020 release. (2020) doi:10.22022/IACC/03-2021.17115.
Pai, S., Emmerling, J., Drouet, L., Zerriffi, H. & Jewell, J. Meeting well-below 2°C target would increase energy sector jobs globally. One Earth 4, 1026–1036 (2021).
Eskander, S. M. S. U. & Fankhauser, S. Reduction in greenhouse gas emissions from national climate legislation. Nat. Clim. Change 10, 750–756 (2020).
Meckling, J. & Jenner, S. Varieties of market-based policy: Instrument choice in climate policy. Environ. Polit. 25, 853–874 (2016).
Bataille, C., Guivarch, C., Hallegatte, S., Rogelj, J. & Waisman, H. Carbon prices across countries. Nat. Clim. Change 8, 648–650 (2018).
Hafstead, M. Federal Climate Policy 102: Economy-Wide Policy. Resources for the Future https://www.rff.org/publications/explainers/federal-climate-policy-102-economy-wide-policies/ (2021).
Pizer, W., Burtraw, D., Harrington, W., Newell, R. & Sanchirico, J. Modeling Economy-wide vs Sectoral Climate Policies Using Combined Aggregate-Sectoral Models. Energy J. 27, 135–168 (2006).
Martin, G. & Saikawa, E. Effectiveness of state climate and energy policies in reducing power-sector CO2 emissions. Nat. Clim. Change 7, 912–919 (2017).
Vogt-Schilb, A., Hallegatte, S. & De Gouvello, C. Marginal abatement cost curves and the quality of emission reductions: a case study on Brazil. Clim. Policy 15, 703–723 (2015).
Schmidt, J., Helme, N., Lee, J. & Houdashelt, M. Sector-based approach to the post-2012 climate change policy architecture. Clim. Policy 8, 494–515 (2008).
Lutsey, N. & Sperling, D. America’s bottom-up climate change mitigation policy. Energy Policy 36, 673–685 (2008).
Wood, T., Reeve, A. & Ha, J. Towards net zero: Practical policies to reduce industrial emissions. Grathan Inst. (2021).
Grubb, M. Tackling Carbon Leakage: Sector-Specific Solutions for an World of Unequal Carbon Prices. Carbon Trust http://www.carbontrust.com/resources/reports/advice/tackling-carbon-leakage-sector-specific-solutions (2010).
Luderer, G., Pietzcker, R. C., Kriegler, E., Haller, M. & Bauer, N. Asia’s role in mitigating climate change: A technology and sector specific analysis with ReMIND-R. Energy Econ. 34, S378–S390 (2012).
Roelfsema, M. et al. Reducing global GHG emissions by replicating successful sector examples: the ‘good practice policies’ scenario. Clim. Policy 18, 1103–1113 (2018).
Singh, A., Winchester, N. & Karplus, V. J. EVALUATING INDIA’S CLIMATE TARGETS: THE IMPLICATIONS OF ECONOMY-WIDE AND SECTOR-SPECIFIC POLICIES. Clim. Change Econ. 10, 1950009 (2019).
European Commission. Carbon leakage. https://climate.ec.europa.eu/eu-action/eu-emissions-trading-system-eu-ets/free-allocation/carbon-leakage_en (n.d).
Ross Morrow, W., Gallagher, K. S., Collantes, G. & Lee, H. Analysis of policies to reduce oil consumption and greenhouse-gas emissions from the US transportation sector. Energy Policy 38, 1305–1320 (2010).
RGGI. The Regional Greenhouse Gas Initiative (RGGI). https://www.rggi.org/ (2024).
Environment and Climate Change Canada. Exploring Approaches for Canada’s Transition to Net-Zero Emissions . Canada’s Long-Term Strategy Submission to the United Nations Framework Convention on Climate Change. https://unfccc.int/sites/default/files/resource/LTS%20Full%20Draft_Final%20version_oct31.pdf (2022).
United States Department of State & and the United States Executive Office of the President,. The Long-Term Strategy of the United States: Pathways to Net-Zero Greenhouse Gas Emissions by 2050. https://unfccc.int/sites/default/files/resource/US-LongTermStrategy-2021.pdf (2021).
The Government of Republic of Korea. 2050 Carbon Neutral Strategy of the Republic of Korea towards a Sustainable and Green Society. https://unfccc.int/sites/default/files/resource/LTS1_RKorea.pdf (2020).
European Council. European Green Deal. https://www.consilium.europa.eu/en/policies/green-deal/ (2024).
Byers, E., Krey, V., Kriegler, E., Riahi, K. & Schaeffer, R. AR6 Scenario Explorer and Database hosted by IIASA. https://data.ece.iiasa.ac.at/ar6/#/workspaces/2123.
Edelenbosch, O. et al. Reducing Sectoral Hard to Abate Emissions to Limit Reliance of Carbon Dioxide Removal in 1.5°C Scenarios. https://www.researchsquare.com/article/rs-3182402/v1 (2023) doi:10.21203/rs.3.rs-3182402/v1.
Anderson, K. et al. Controversies of carbon dioxide removal. Nat. Rev. Earth Environ. 1–7 (2023) doi:10.1038/s43017-023-00493-y.
Smith, S. M. et al. The State of Carbon Dioxide Removal - 1st Edition. http://dx.doi.org/10.17605/OSF.IO/W3B4Z (2023) doi:10.17605/OSF.IO/W3B4Z.
Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018).
de Coninck, H. & Benson, S. M. Carbon Dioxide Capture and Storage: Issues and Prospects. Annu. Rev. Environ. Resour. 39, 243–270 (2014).
Global CCS Institue. The Global Status of CCS: 2015 Summary Report. (2015).
UNEP. Emissions Gap Report 2023. http://www.unep.org/resources/emissions-gap-report-2023 (2023).
Liu, H. et al. Deployment of hydrogen in hard-to-abate transport sectors under limited carbon dioxide removal (CDR): Implications on global energy-land-water system. Renew. Sustain. Energy Rev. 184, 113578 (2023).
Ampah, J. D. et al. Prioritizing Non-Carbon Dioxide Removal Mitigation Strategies Could Reduce the Negative Impacts Associated with Large-Scale Reliance on Negative Emissions. Environ. Sci. Technol. (2024) doi:10.1021/acs.est.3c06866.
Adun, H., Ampah, J. D., Bamisile, O. & Hu, Y. The synergistic role of carbon dioxide removal and emission reductions in achieving the Paris Agreement goal. Sustain. Prod. Consum. (2024) doi:10.1016/j.spc.2024.01.004.
Hart, P. S., Campbell-Arvai, V., Wolske, K. S. & Raimi, K. T. Moral hazard or not? The effects of learning about carbon dioxide removal on perceptions of climate mitigation in the United States. Energy Res. Soc. Sci. 89, 102656 (2022).
Ampah, J. D. et al. Deployment expectations of multi-gigatonne scale carbon removal could have adverse impacts on Asia’s energy-water-land nexus. Nat. Commun. 15, 6342 (2024).
Höglund, R., Mitchell-Larson, E. & Delerce, S. How to Scale Carbon Removal without Undermining Emission Cuts. https://carbongap.org/how-to-scale-carbon-removal-without-undermining-emission-cuts/ (2023).
McLaren, D. P., Tyfield, D. P., Willis, R., Szerszynski, B. & Markusson, N. O. Beyond “Net-Zero”: A Case for Separate Targets for Emissions Reduction and Negative Emissions. Front. Clim. 1, (2019).
CAT. Climate Action Tracker. https://climateactiontracker.org/ (2023).
Fyson, C. L., Baur, S., Gidden, M. & Schleussner, C.-F. Fair-share carbon dioxide removal increases major emitter responsibility. Nat. Clim. Change 10, 836–841 (2020).
Pozo, C., Galán-Martín, Á., Reiner, D. M., Mac Dowell, N. & Guillén-Gosálbez, G. Equity in allocating carbon dioxide removal quotas. Nat. Clim. Change 10, 640–646 (2020).
Kanitkar, T., Mythri, A. & Jayaraman, T. Equity assessment of global mitigation pathways in the IPCC Sixth Assessment Report. Clim. Policy 0, 1–20 (2024).
Robiou du Pont, Y. et al. Equitable mitigation to achieve the Paris Agreement goals. Nat. Clim. Change 7, 38–43 (2017).
Climate Analytics. 1.5°C national pathway explorer. https://1p5ndc-pathways.climateanalytics.org/ (2023).
Bednar, J. et al. Operationalizing the net-negative carbon economy. Nature 596, 377–383 (2021).
Luderer, G. et al. Impact of declining renewable energy costs on electrification in low-emission scenarios. Nat. Energy 7, 32–42 (2022).
Rogelj, J. et al. A new scenario logic for the Paris Agreement long-term temperature goal. Nature 573, 357–363 (2019).
Iyer, G. et al. Ratcheting of climate pledges needed to limit peak global warming. Nat. Clim. Change 12, 1129–1135 (2022).
Holz, C., Siegel, L. S., Johnston, E., Jones, A. P. & Sterman, J. Ratcheting ambition to limit warming to 1.5 °C – trade-offs between emission reductions and carbon dioxide removal. Environ. Res. Lett. 13, 064028 (2018).
Wohlfarth, K., Worrell, E. & Eichhammer, W. Energy efficiency and demand response – two sides of the same coin? Energy Policy 137, 111070 (2020).
Jarmul, S. et al. Climate change mitigation through dietary change: a systematic review of empirical and modelling studies on the environmental footprints and health effects of ‘sustainable diets’. Environ. Res. Lett. 15, 123014 (2020).
Kim, B. F. et al. Country-specific dietary shifts to mitigate climate and water crises. Glob. Environ. Change 62, 101926 (2020).
Mariam, N., Valerie, K., Karin, D., Angelika, W.-R. & Nina, L. Limiting food waste via grassroots initiatives as a potential for climate change mitigation: a systematic review. Environ. Res. Lett. 15, 123008 (2020).
Bond-Lamberty, B. et al. JGCRI/gcam-core: GCAM 5.4. (2021) doi:10.5281/zenodo.5093192.
Bergero, C. et al. An integrated assessment of a low coal low nuclear future energy system for Taiwan. Energy Clim. Change 2, 100022 (2021).
Bond-Lamberty, B. et al. JGCRI/Gcam-Core: GCAM 6.0. https://zenodo.org/record/6619287 (2022) doi:10.5281/ZENODO.6619287.
Calvin, K. et al. GCAM v5.1: representing the linkages between energy, water, land, climate, and economic systems. Geosci. Model Dev. 12, 677–698 (2019).
Speizer, S. et al. A zero-emissions global transportation sector: Advanced technologies and their energy and environmental implications. ResearchSquare (2023) doi:http://dx.doi.org/10.21203/rs.3.rs-2921936/v1.
European Commission. Europe’s 2040 Climate Target and Path to Climate Neutrality by 2050 Building a Sustainable, Just and Prosperous Society. (2024).
China. China’s Mid-Century Long-Term Low Greenhouse Gas Emission Development Strategy. https://unfccc.int/documents/307765 (2021).
Lenzi, D. The ethics of negative emissions. Glob. Sustain. 1, e7 (2018).
Realmonte, G. et al. An inter-model assessment of the role of direct air capture in deep mitigation pathways. Nat. Commun. 10, 3277 (2019).
Fuhrman, J. et al. Diverse carbon dioxide removal approaches could reduce impacts on the energy–water–land system. Nat. Clim. Change (2023) doi:10.1038/s41558-023-01604-9.
Pradhan, S. et al. Effects of Direct Air Capture Technology Availability on Stranded Assets and Committed Emissions in the Power Sector. Front. Clim. 3, 660787 (2021).
Yang, P. et al. The global mismatch between equitable carbon dioxide removal liability and capacity. Natl. Sci. Rev. 10, nwad254 (2023).
IEA. Global energy-related CO2 emissions by sector. IEA https://www.iea.org/data-and-statistics/charts/global-energy-related-co2-emissions-by-sector (2020).
Jafari, M., Botterud, A. & Sakti, A. Decarbonizing power systems: A critical review of the role of energy storage. Renew. Sustain. Energy Rev. 158, 112077 (2022).
Khan, I. Importance of GHG emissions assessment in the electricity grid expansion towards a low-carbon future: A time-varying carbon intensity approach. J. Clean. Prod. 196, 1587–1599 (2018).
Bistline, J. E. T. & Blanford, G. J. The role of the power sector in net-zero energy systems. Energy Clim. Change 2, 100045 (2021).
He, G. et al. Rapid cost decrease of renewables and storage accelerates the decarbonization of China’s power system. Nat. Commun. 11, 2486 (2020).
Heptonstall, P. J. & Gross, R. J. K. A systematic review of the costs and impacts of integrating variable renewables into power grids. Nat. Energy 6, 72–83 (2021).
Gielen, D. et al. The role of renewable energy in the global energy transformation. Energy Strategy Rev. 24, 38–50 (2019).
Aquila, G., Pamplona, E. de O., Queiroz, A. R. de, Rotela Junior, P. & Fonseca, M. N. An overview of incentive policies for the expansion of renewable energy generation in electricity power systems and the Brazilian experience. Renew. Sustain. Energy Rev. 70, 1090–1098 (2017).
Mercure, J.-F. et al. Reframing incentives for climate policy action. Nat. Energy 6, 1133–1143 (2021).
Richler, J. Solar PV adoption: Incentives and behaviour. Nat. Energy 2, 1–1 (2017).
Papadis, E. & Tsatsaronis, G. Challenges in the decarbonization of the energy sector. Energy 205, 118025 (2020).
Arent, D. J. et al. Challenges and opportunities in decarbonizing the U.S. energy system. Renew. Sustain. Energy Rev. 169, 112939 (2022).
Khanna, N., Lu, H., Fridley, D. & Zhou, N. Near and long-term perspectives on strategies to decarbonize China’s heavy-duty trucks through 2050. Sci. Rep. 11, 20414 (2021).
Woody, M., Keoleian, G. A. & Vaishnav, P. Decarbonization potential of electrifying 50% of U.S. light-duty vehicle sales by 2030. Nat. Commun. 14, 7077 (2023).
Bergero, C. et al. Pathways to net-zero emissions from aviation. Nat. Sustain. (2023) doi:10.1038/s41893-022-01046-9.
Bistline, J. E. T. & Blanford, G. J. Impact of carbon dioxide removal technologies on deep decarbonization of the electric power sector. Nat. Commun. 12, 3732 (2021).
Liu, H. et al. Potential benefits and trade-offs associated with hydrogen transition under diverse carbon dioxide removal strategies. Sci. Bull. (2023) doi:10.1016/j.scib.2023.10.033.

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Sector-specific and carbon removal targets could limit adverse impacts of climate change and promote sustainability

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