Technical ReportPDF Available

The State of Carbon Dioxide Removal - 1st Edition

Authors:
  • German Institute for International and Security Affairs (SWP)

Abstract and Figures

A global, independent scientific assessment of Carbon Dioxide Removal
Content may be subject to copyright.
... The majority of historical and anticipated CDR comes from vegetation and soils, and especially in forests. However, levels of CDR have been declining because of a combination of changes in forest conditions and land uses [3][4][5]. Future levels of land-based CDR will be determined by a combination of policies, forest biology, and market-driven demands for land in various uses. Projections of policy effects need to account for land-use and forest changes and how these two dynamics interact. ...
... We use FIA plot data to define the current distribution of forest attributes (F m vectors), transition matrixes (T m , Eq. 5), and the forest carbon stock density coefficients (d m , Eq. 6). 4 FIA inventory records include estimates of forest carbon stock based on measured tree biomass and a set of ancillary variables for six carbon pools (live-tree biomass, downed dead wood, standing dead trees, understory vegetation, forest floor and litter, and soil organic carbon; see Woodall et al. 2015). We use the CARBON function in the R package rFIA [28] to query the FIA databases for the 48 conterminous states for plot estimates of per acre carbon stocks along with identifiers for age (which we convert to age class 1…L) and forest class (m). ...
... Using this regression approach rather than average observed densities addresses data missing for some age classes and high variability in older average densities linked to small samples. The predicted carbon density curves (Table S1) are summarized in Fig. 2. The highest density of carbon is found in mature forests in the 4 In some cases, individual plots may span more than one forest stand, defining "condition" components of the plot. We use condition records to generate estimates. ...
Article
Full-text available
Background Carbon dioxide removal from the atmosphere (CDR) is a critical component of strategies for restricting global warming to 1.5°C and is expected to come largely from the sequestration of carbon in vegetation. Because CDR rates have been declining in the United States, in part due to land use changes, policy proposals are focused on altering land uses, through afforestation, avoided deforestation, and no-net-loss strategies. Estimating policy effects requires a careful assessment of how land uses interact with forest conditions to determine future CDR. Results We evaluate how alternative specifications of land use-forest condition interactions in the United States affect projections of CDR using a model that mirrors land sector net emission inventories generated by the US government (EPA). Without land use change, CDR declines from 0.826 GT/yr in 2017 to 0.596 GT/yr in 2062 (28%) due to forest aging and disturbances. For a land use scenario that extends recent rates of change, we compare CDR estimated based on net changes in land use (Net Change model) and estimates that separately account for the distinct CDR implications of forest losses and forest gains (Component Change model). The Net Change model, a common specification, underestimates the CDR losses of land use by about 56% when compared with the Component Change models. We also estimate per hectare CDR losses from deforestation and gains from afforestation and find that afforestation gains lag deforestation losses in every ecological province in the US. Conclusions Net Change approaches substantially underestimate the impact of land use change on CDR and should be avoided. Component Change models highlight that avoided deforestation may provide up to twice the CDR benefits as increased afforestation—though preference for one policy over the other would require a cost assessment. The disparities in the CDR impacts of afforestation and deforestation indicate that no-net-loss policies could mitigate some CDR losses but would lead to overall declines in CDR for our 45-year time horizon. Over a much longer period afforestation could capture more of the losses from deforestation but at a timeframe inconsistent with most climate change policy efforts.
... 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][39][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. ...
... In a high renewables pathway, global novel CDR has to grow by a factor of 450 by 2050 compared to 1700folds in a high CDR pathway 36 . ...
... 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. ...
Preprint
Full-text available
This study proposes a new policy pathway for countries' long-term mitigation strategies to achieve better impacts on global climate change targets and sustainable development goals. Shifting away from the conventional economy-wide policies, we use a new modeling approach and dataset to propose pathways that follow explicit timelines for completely decarbonized transport and electricity sectors alongside carbon dioxide removal (CDR) targets. Here, we also consider equitable pathways where relative to developed countries, less developed countries with limited financial resources to support their mitigation efforts are allowed to attain completely decarbonized transport and electricity emissions later and are exempted from excessive CDR obligations. Our analysis reveals that adopting this sector-specific and CDR strategy could lead to a potential reduction in residual emissions by up to 35% and a 35–45% decrease in carbon removal requirements. Furthermore, compared to economy-wide policies, our proposed strategy could reduce staple food prices, mitigation costs, water and fertilizer demands for bioenergy crop cultivation by up to 23%, 10%, 35%, and 30%, respectively.
... Given the need for large scale carbon dioxide removal (CDR) to meet the temperature goals of the Paris Agreement [1,2], direct air capture (DAC) of CO 2 is gaining increasing attention and receiving growing private sector investment, advanced procurement commitments, and public policy support. DAC is energy intensive given the low concentration (< 0.1%) of CO 2 in ambient air, but offers relatively strong verification of removals (when combined with permanent geologic storage) and limited land constraints to scale. ...
... In the previous section, we incorporated such policies and prevented retirement of existing nuclear generation in ERCOT in our capacity expansion to 2035. 1 In the case of new nuclear plants, high capital costs (well above $5000/kW for recent projects in the U.S. and Europe) have meant that new nuclear capacity is economically unattractive. Indeed, when assuming a capital costs for new reactors of roughly $5000/kW (from [21]), our capacity expansion results in no new nuclear plants built in this case study (which lacks any binding carbon constraints; see Fig. 2). ...
Article
Direct air capture (DAC) of carbon dioxide (CO2) is energy intensive given the low concentration (<0.1%) of CO2 in ambient air, but offers relatively strong verification of removals and limited land constraints to scale. Lower temperature solid sorbent based DAC could be coupled on-site with low carbon thermal generators such as nuclear power plants. Here, we undertake a unique interdisciplinary study combining process engineering with a detailed macro-energy system optimization model to evaluate the system-level impacts of such plant designs in the Texas electricity system. We contrast this with using grid power to operate a heat pump to regenerate the sorbent. Our analysis identifies net carbon removal costs accounting for power system impacts and resulting indirect CO2 emissions from DAC energy consumption. We find that inefficient configurations of DAC at a nuclear power plant can lead to increases in power sector emissions relative to a case without DAC, at a scale that would cancel out almost 50% of the carbon removal from DAC. Net removal costs for the most efficient configurations increase by roughly 18% once indirect power system-level impacts are considered, though this is comparable to the indirect systems-level emissions from operating grid-powered heat pumps for sorbent regeneration. Our study therefore highlights the need for DAC energy procurement to be guided by consideration of indirect emission impacts on the electricity system. Finally, DAC could potentially create demand pull for zero carbon firm generation, accelerating decarbonization relative to a world without such DAC deployment. We find that DAC operators would have to be willing to pay existing or new nuclear power plants roughly 3080/tCO2or30–80/tCO2 or 150–400/tCO2 respectively, for input energy, to enable nuclear plants to be economically competitive in least cost electricity markets that do not have carbon constraints or subsidies for nuclear energy.
... Here, we assess how states rely on CDR in their climate strategies, and the risks associated with this dependence. Disclosure of CDR dependence, where it exists, is primarily limited to use of removals to 30 counterbalance residual emissions and reach net zero, rather than to withdraw overshoot emissions (or 1 We adopt the definitions of novel and conventional CDR from Geden, Smith and Cowie (2024). Accordingly, Direct Air Carbon Capture and Storage (DACCS), Bioenergy Carbon Capture and Storage (BECCS), biochar, enhanced rock weathering and ocean alkalinity enhancement are classed as 'novel', and afforestation, reforestation, agroforestry, forest management, soil carbon sequestration, peatland and coastal wetland restoration and durable wood products are 'conventional'. ...
Preprint
Full-text available
Achieving the Paris Agreement’s long-term temperature goal of limiting global warming well-below 2°C while pursuing efforts to limit it to 1.5°C requires rapid and sustained reductions in greenhouse gas emissions and CO2 to be withdrawn from the atmosphere and safely stored. However, pathways consistent with the Paris long-term temperature goal span a wide range of emission reductions in coming years: the IPCC indicates 34-60% cuts in greenhouse gas (GHG) emissions in 2030 relative to 2019. This range is a major source of policy uncertainty. A key determinant of the rate at which emissions must be reduced this decade is the extent to which CO2 removal (CDR) is relied on to withdraw emissions from the atmosphere. Nearly a decade after the adoption of the Paris Agreement, we evaluate the dependence on CDR of 71 states, primarily in their near and long-term climate strategies submitted to the UNFCCC by May 2024, and the associated risks. Our analysis finds substantial ambiguities in how states plan to meet their climate targets. A feature of this ambiguity is that states expect to rely heavily on novel and conventional CDR options to meet their climate goals, and in some cases, rely on removals delivered in other states’ territories. Pathways that overshoot 1.5°C and use CDR to remove emissions produced in excess of the 1.5°C-aligned carbon budget will result in more severe climate change impacts and higher risks of crossing planetary tipping points. Moreover, states’ disclosed reliance on CDR is highly exposed to risks to its delivery, and non-delivery of planned CDR would raise global temperatures further, worsening impacts of climate change. Our findings provide a basis for enhanced scrutiny of states’ targets. The risks associated with heavy reliance on CDR to meet climate goals indicate that states should prioritise pathways that minimise overshoot and the reliance on CDR to reach net-zero CO2 emissions.
... Radical and frequently contested climate intervention technologies such as carbon removal and solar geoengineering are attracting increasing attention from researchers, investors, and policymakers as the adverse impacts of climate change are increasingly evident [1][2][3] . ...
Article
Full-text available
Climate intervention technologies such as carbon dioxide removal and solar geoengineering are becoming more actively considered as solutions to global warming. The demographic aspects of the public serve as a core determinant of social vulnerability and the ability for people to cope with, or fail to cope with, exposure to heat waves, air pollution, or disruptions in access to modern energy services. This study examines public preferences for 10 different climate interventions utilizing an original, large-scale, cross-country set of nationally representative surveys in 30 countries. It focuses intently on the demographic dimensions of gender, youth and age, poverty, and income as well as intersections and interactions between these categories. We find that support for the more engineered forms of carbon removal decreases with age. Gender has little effect overall. Those in poverty and the Global South are nearly universally more supportive of climate interventions of various types.
... Some level of carbon dioxide removal (CDR) will be required to balance residual emissions at the point of net zero, though both the scale of CDR and the amount of residual emissions remain contested 2 . Multiple studies now assess the current and pledged level of CDR in government and corporate climate pledges for net zero [3][4][5] . Yet these assessments focus on quantifying removals in terms of tonnes of CO 2 , which leaves open the question of what form these removals will take. ...
Article
Full-text available
Achieving net-zero climate targets requires some level of carbon dioxide removal. Current assessments focus on tonnes of CO2 removed, without specifying what form these removals will take. Here, we show that countries’ climate pledges require approximately 1 (0.9–1.1) billion ha of land for removals. For over 40% of this area, the pledges envisage the conversion of existing land uses to forests, while the remaining area restores existing ecosystems and land uses. We analyse how this demand for land is distributed geographically and over time. The results are concerning, both in terms of the aggregate area of land, but also the rate and extent of land use change. Our findings demonstrate a gap between governments’ expected reliance on land and the role that land can realistically play in climate mitigation. This adds another layer to the observed shortcomings of national climate pledges and indicates a need for more transparency around the role of land in national climate mitigation plans.
Chapter
Full-text available
Humanity is in a race to reduce carbon dioxide levels in the atmosphere. Emissions must be reduced while also accelerating net carbon dioxide removal (CDR). Historically, carbon removal has been shouldered by “green” and “blue” nature—land, coastal areas, and ocean. With the world’s growing population, impacts from climate change, and increasing urbanization, it is clear nature cannot handle all the CDR needed. Natural systems are under threat, risking their ability to maintain the same rate of carbon sequestration. Man-made technology must deliver more. The IPCC Assessment Report 6 (AR6) highlights a mix of nature- and technology-based CDR solutions that will be needed. Here, we look at a new CDR solution for the construction industry, which is responsible for 38% of global CO 2 emissions. Since climate change is only increasing demand for construction, we must reimagine how and what we build with. We need building technologies that can help keep their own industry’s emissions in check while also reducing CO 2 from the atmosphere. This is where “grey carbon” comes in. Like its blue and green cousins, grey carbon offers net carbon removal from man-made technology and presents a pathway that delinks pollution and development. Here, we use a case example of how the Bahamas is turning to a grey carbon building product to respond to housing demand and climate adaptation. We describe the science behind this CDR technology and apply financial valuation techniques to calculate the monetary value that could be derived from the grey carbon credits. We show how grey carbon delivers climate, nature, and community benefits from the following: CO 2 avoidance and removal during production, longer-term carbon removal as the materials continue to weather, ocean protection through reduced brine waste, and social benefits from the sale of grey carbon credits. We show that a 1250 ft ² home built with this cement can deliver 170.94 tCO 2 e credits over 20 years for a present value of 38,145perhomeand38,145 per home and 57.22 million for 1500 homes. We conclude that grey carbon can mitigate emissions from the built world while also helping to deliver a future in which the biosphere and Technosphere, blue, green, and grey climate solutions, coexist as allies for human well-being and climate stabilization.
Article
Full-text available
The climate mitigation potential of terrestrial carbon dioxide removal (tCDR) methods depends critically on the timing and magnitude of their implementation. In our study, we introduce different measures of efficiency to evaluate the carbon removal potential of afforestation and reforestation (AR) and bioenergy with carbon capture and storage (BECCS) under the low-emission scenario SSP1-2.6 and in the same area. We define efficiency as the potential to sequester carbon in the biosphere in a specific area or store carbon in geological reservoirs or woody products within a certain time. In addition to carbon capture and storage (CCS), we consider the effects of fossil fuel substitution (FFS) through the usage of bioenergy for energy production, which increases the efficiency through avoided CO2 emissions. These efficiency measures reflect perspectives regarding climate mitigation, carbon sequestration, land availability, spatiotemporal dynamics, and the technological progress in FFS and CCS. We use the land component JSBACH3.2 of the Max Planck Institute Earth System Model (MPI-ESM) to calculate the carbon sequestration potential in the biosphere using an updated representation of second-generation bioenergy plants such as Miscanthus. Our spatially explicit modeling results reveal that, depending on FFS and CCS levels, BECCS sequesters 24–158 GtC by 2100, whereas AR methods sequester around 53 GtC on a global scale, with BECCS having an advantage in the long term. For our specific setup, BECCS has a higher potential in the South American grasslands and southeast Africa, whereas AR methods are more suitable in southeast China. Our results reveal that the efficiency of BECCS to sequester carbon compared to “nature-based solutions” like AR will depend critically on the upscaling of CCS facilities, replacing fossil fuels with bioenergy in the future, the time frame, and the location of tCDR deployment.
Article
Full-text available
Zdając sobie sprawę ze znaczenia, jakie ma usuwanie dwutlenku węgla dla realizacji globalnych i unijnych celów klimatycznych, Komisja Europejska we wniosku ogłoszonym 30 listopada 2022 r. zaproponowała ramy prawne certyfikacji dobrowolnego usuwania dwutlenku węgla (CDR). Starania Unii Europejskiej o stworzenie systemu certyfikacji CDR są ważną inicjatywą w tym zakresie, ale wiążą się z kluczowymi wyzwaniami, które powinny zostać pokonane w trakcie trwających procesów legislacyjnych. Cel opracowania stanowi ocena treści rzeczonego projektu rozporządzenia z punktu widzenia jego skuteczności jako narzędzia klimatycznego.
Article
Full-text available
Despite the importance of carbon dioxide removal (CDR) in most climate change mitigation scenarios that limit warming to well below 2°C, the study of CDR is still a nascent field with basic questions to be resolved. Crucially, it is not known how much CDR is currently deployed at a global scale, nor how that compares to mitigation scenario estimates. Here, we address this problem by developing an estimate of global current CDR activity. We draw on national greenhouse gas inventory data combined with CDR registries and commercial databases to estimate that global anthropogenic activity presently generates ~1985 MtCO2yr-1 of atmospheric removals. Almost all of these - 1983 MtCO2yr-1- are removals from land-use, land-use change and forestry (LULUCF). Non-land-management CDR projects such as bioenergy with carbon capture and storage (BECCS), direct air capture with carbon capture and storage (DACCS) and biochar remove only about 2 MtCO2yr-1.We compare this estimate with Shared Socioeconomic Pathways (SSPs) projections of CDR deployed in “well-below 2°C” mitigation pathways. In so doing we demonstrate current CDR deployment would need to grow exponentially to keep the world aligned with most “well-below 2°C” scenarios, which see CDR deployment growing between 75 and 100% per year between 2020 and 2030, adding ~300-2500 MtCO2 in total CDR capacity. To conclude we discuss uncertainties related to our estimates, and suggest priorities for the future collection and management of CDR data, particularly related to the role of the land sink in generating CDR.
Article
Full-text available
The deployment of carbon dioxide removal is essential to reach global and national net-zero emissions targets, but little attention has been paid to its practical deployment by countries. Here, we analyse how carbon dioxide removal methods are integrated into 41 of the 50 Long-term Low Emission Development Strategies submitted to the United Nations Framework Convention on Climate Change (UNFCCC), before 2022. We show that enhancing forest and soil carbon sinks are the most advocated strategies but are only explicitly quantified in 12. Residual emissions by 2050 are only quantified in 20 strategies and most of them use forests to achieve national net-zero targets. Strategies that quantify both residual emissions and carbon dioxide removal identify national constraints, such as wildfire risks to forests and limited geological CO 2 storage capacity. These strategies also highlight the need for international cooperation. Taken together, we suggest that the UNFCCC should urgently strengthen its reporting requirements on long-term national climate strategies.
Article
Full-text available
Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodologies to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFOS) are based on energy statistics and cement production data, while emissions from land-use change (ELUC), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly, and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO2 sink (SLAND) is estimated with dynamic global vegetation models. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the year 2021, EFOS increased by 5.1 % relative to 2020, with fossil emissions at 10.1 ± 0.5 GtC yr-1 (9.9 ± 0.5 GtC yr-1 when the cement carbonation sink is included), and ELUC was 1.1 ± 0.7 GtC yr-1, for a total anthropogenic CO2 emission (including the cement carbonation sink) of 10.9 ± 0.8 GtC yr-1 (40.0 ± 2.9 GtCO2). Also, for 2021, GATM was 5.2 ± 0.2 GtC yr-1 (2.5 ± 0.1 ppm yr-1), SOCEAN was 2.9 ± 0.4 GtC yr-1, and SLAND was 3.5 ± 0.9 GtC yr-1, with a BIM of -0.6 GtC yr-1 (i.e. the total estimated sources were too low or sinks were too high). The global atmospheric CO2 concentration averaged over 2021 reached 414.71 ± 0.1 ppm. Preliminary data for 2022 suggest an increase in EFOS relative to 2021 of +1.0 % (0.1 % to 1.9 %) globally and atmospheric CO2 concentration reaching 417.2 ppm, more than 50 % above pre-industrial levels (around 278 ppm). Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2021, but discrepancies of up to 1 GtC yr-1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extratropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set. The data presented in this work are available at 10.18160/GCP-2022 (Friedlingstein et al., 2022b).
Article
Full-text available
Rapidly decarbonizing the global energy system is critical for addressing climate change, but concerns about costs have been a barrier to implementation. Most energy-economy models have historically underestimated deployment rates for renewable energy technologies and overestimated their costs. These issues have driven calls for alternative approaches and more reliable technology forecasting methods. Here, we use an approach based on probabilistic cost forecasting methods that have been statistically validated by backtesting on more than 50 technologies. We generate probabilistic cost forecasts for solar energy, wind energy, batteries, and electrolyzers, conditional on deployment. We use these methods to estimate future energy system costs and explore how technology cost uncertainty propagates through to system costs in three different scenarios. Compared to continuing with a fossil fuel-based system, a rapid green energy transition will likely result in overall net savings of many trillions of dollars—even without accounting for climate damages or co-benefits of climate policy.
Article
Full-text available
Countries and companies with net-zero emissions targets are considering carbon removal strategies to compensate for remaining greenhouse gas emissions. Soil carbon sequestration is one such carbon removal strategy, and policy and corporate interest is growing in figuring out how to motivate farmers to sequester more carbon. But how do farmers in various cultural and geographic contexts view soil carbon sequestration as a climate mitigation or carbon removal strategy? This article systematically reviews the empirical social science literature on farmer adoption of soil carbon sequestration practices and participation in carbon markets or programs. The article finds thirty-seven studies over the past decade that involve empirical research with soil carbon sequestering practices in a climate context, with just over a quarter of those focusing on the Global South. A central finding is co-benefits are a strong motivator for adoption, especially given minimal carbon policies and low carbon prices. Other themes in the literature include educational and cultural barriers to adoption, the difference between developing and developed world contexts, and policy preferences among farmers for soil carbon sequestration incentives. However, we argue that given the rising profile of technical potentials and carbon credits, this peer-reviewed literature on the social aspects of scaling soil carbon sequestration is quite limited. We discuss why the social science literature is so small, and what this research gap means for efforts to achieve higher levels of soil carbon sequestration. We conclude with a ten-point social science research agenda for social science on soil carbon—and some cautions about centering carbon too strongly in research and policy.
Article
Full-text available
The restoration of tropical forests has become a popular nature-based solution for climate change mitigation, protection of biodiversity and improving the livelihoods of local populations. The Bonn Challenge and the UN Decade on Ecosystem Restoration underscore the international momentum of the restoration movement, with many countries committing to restore millions of hectares of deforested and degraded land in the next decade. Brazil and Indonesia are among the ones with the most ambitious restoration commitments globally. Since both their economies are highly dependent on the export of agricultural commodities, reconciling economic growth with environmental sustainability will be a major policy challenge. In this paper, we i) identify the main restoration targets and the policies supporting their implementation in both countries, ii) provide a descriptive overview of these restoration-supportive policies, and iii) discuss the main challenges that Brazil and Indonesia face in the implementation of their restoration commitments. We find that Brazil has an explicit and dedicated strategy to achieve its restoration target, but that recent political developments have weakened environmental governance in the country, affecting the implementation of its restoration commitment. In the case of Indonesia, we find that the government has rather focused and progressed on the restoration of peatlands and mangroves, whereas its commitment to restore forestlands has yet to benefit from a dedicated plan that allows to coordinate policies and agencies’ efforts towards the achievement of its restoration target.
Book
Greenhouse gas removal (GGR) technologies can remove greenhouse gases such as carbon dioxide from the atmosphere. Most of the current GGR technologies focus on carbon dioxide removal, these include afforestation and reforestation, bioenergy with carbon capture and storage, direct air capture, enhanced weathering, soil carbon sequestration and biochar, ocean fertilisation and coastal blue carbon. GGR technologies will be essential in limiting global warning to temperatures below 1.5°C (targets by the IPCC and COP21) and will be required to achieve deep reductions in atmospheric CO2 concentration. In the context of recent legally binding legislation requiring the transition to a net zero emissions economy by 2050, GGR technologies are broadly recognised as being indispensable. This book provides the most up-to-date information on GGR technologies that provide removal of atmosphere CO2, giving insight into their role and value in achieving climate change mitigation targets. Chapters discuss the issues associated with commercial development and deployment of GGRs, providing potential approaches to overcome these hurdles through a combination of political, economic and R&D strategies. With contributions from leaders in the field, this title is an indispensable resource for graduate students and researchers in academia and industry, working in chemical engineering, mechanical engineering and energy policy.
Article
Meeting goals for ‘net zero’ emissions may require the removal of previously emitted carbon dioxide from the atmosphere. One proposal, enhanced rock weathering, aims to speed up the weathering processes of rocks by crushing them finely and spreading them on agricultural land. Public perceptions of enhanced rock weathering and its wider social and environmental implications will be a critical factor determining its potential; we use six 2-day deliberative workshops in England, Wales and Illinois to understand public views. Consideration of enhanced rock weathering deployment in tropical countries led participants to frame it from a social justice perspective, which had been much less prevalent when considering Western agricultural contexts, and generated assumptions of increased scale, which heightened concerns about detrimental social and environmental impacts. Risk perceptions relating to ‘messing with nature’ became amplified when participants considered enhanced rock weathering in relation to ‘iconic’ environments such as the oceans and rainforest.