Strategies for mitigation of climate change: a review

Environmental Chemistry Letters, Journal Year: 2020, Volume and Issue: 18(6), P. 2069 - 2094

Published: July 30, 2020

Abstract Climate change is defined as the shift in climate patterns mainly caused by greenhouse gas emissions from natural systems and human activities. So far, anthropogenic activities have about 1.0 °C of global warming above pre-industrial level this likely to reach 1.5 between 2030 2052 if current emission rates persist. In 2018, world encountered 315 cases disasters which are related climate. Approximately 68.5 million people were affected, economic losses amounted $131.7 billion, storms, floods, wildfires droughts accounted for approximately 93%. Economic attributed 2018 alone almost equal collective incurred over past decade, quite alarming. Furthermore, food, water, health, ecosystem, habitat infrastructure been identified most vulnerable sectors under attack. 2015, Paris agreement was introduced with main objective limiting temperature increase 2 2100 pursuing efforts limit °C. This article reviews strategies abatement, namely conventional mitigation, negative radiative forcing geoengineering. Conventional mitigation technologies focus on reducing fossil-based CO emissions. Negative aiming capture sequester atmospheric carbon reduce dioxide levels. Finally, geoengineering techniques alter earth’s energy budget stabilize or temperatures. It evident that not sufficient meet targets stipulated agreement; therefore, utilization alternative routes appears inevitable. While various presented may still be at an early stage development, biogenic-based sequestration a certain extent mature can deployed immediately.

Language: Английский

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Life cycle assessment of carbon dioxide removal technologies: a critical review

Energy & Environmental Science, Journal Year: 2021, Volume and Issue: 14(4), P. 1701 - 1721

Published: Jan. 1, 2021

This review provides a perspective on how to conduct future Life Cycle Assessment (LCA) studies of carbon dioxide removal technologies in consistent way avoiding common mistakes, which should be addressed aid informed decision making.

Language: Английский

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Assessing the sequestration time scales of some ocean-based carbon dioxide reduction strategies

Environmental Research Letters, Journal Year: 2021, Volume and Issue: 16(10), P. 104003 - 104003

Published: June 16, 2021

Abstract Ocean-based carbon dioxide (CO 2 ) removal (CDR) strategies are an important part of the portfolio approaches needed to achieve negative greenhouse gas emissions. Many ocean-based CDR rely on injecting CO or organic (that will eventually become into ocean interior, enhancing ocean’s biological pump. These not result in permanent sequestration, because currents return injected back surface, where it be brought equilibrium with atmosphere. Here, a model steady state global circulation and mixing is used assess time scales over which interior remains sequestered from There distribution sequestration times for any single discharge location due infinite number pathways connecting at depth sea surface. The resulting probability highly skewed long tail very transit times, making mean much longer than typical scales. Deeper locations sequester purposefully shallower ones median typically decades centuries, approach 1000 years deep North Pacific. Large differences occur both within between major basins, Pacific Indian basins generally having Atlantic Southern Oceans. Assessments made 50 year horizon illustrates that most retained injection depths greater m, several geographic exceptions such as Western Atlantic. Ocean increase upper ecosystem productivity goal exporting more have mainly short-term influence atmospheric levels ∼70% transported surface years. results presented here help plan appropriate can limit climate damage caused by fossil fuel

Language: Английский

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Assessing the influence of ocean alkalinity enhancement on a coastal phytoplankton community

Biogeosciences, Journal Year: 2022, Volume and Issue: 19(23), P. 5375 - 5399

Published: Dec. 1, 2022

Abstract. Ocean alkalinity enhancement (OAE) is a proposed method to counteract climate change by increasing the of surface ocean and thus chemical storage capacity seawater for atmospheric CO2. The impact OAE on marine ecosystems, including phytoplankton communities which make up base food web, largely unknown. To investigate influence communities, we enclosed natural plankton community from coastal Tasmania 22 d in nine microcosms during spring bloom. Microcosms were split into three groups, (1) unperturbed control, (2) unequilibrated treatment where was increased (+495 ± 5.2 µmol kg−1) but CO2 not equilibrium with CO2, (3) equilibrated (+500 3.2 Both treatments have increase inorganic carbon sink 21 %. We found that simulated had significant generally moderate effects various groups heterotrophic bacteria. More pronounced observed diatom silicic acid drawdown biogenic silica build-up reduced at alkalinity. Observed changes affected temporal trends key biogeochemical parameters such as organic matter carbon-to-nitrogen ratio. Interestingly, did noticeably larger (and bacteria) than treatment, even though carbonate chemistry conditions much more severe. This particularly evident occurrence peak bloom experiment, different control. Altogether, inadvertent appear be rather limited relative enormous climatic benefit note, however, detailed widespread investigations responses are required confirm or dismiss this first impression.

Language: Английский

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Ocean alkalinity enhancement – avoiding runaway CaCO₃ precipitation during quick and hydrated lime dissolution

Biogeosciences, Journal Year: 2022, Volume and Issue: 19(15), P. 3537 - 3557

Published: Aug. 1, 2022

Abstract. Ocean alkalinity enhancement (OAE) is a method that can remove carbon dioxide (CO2) from the atmosphere and counteract ocean acidification through dissolution of alkaline minerals. Currently, critical knowledge gaps exist regarding different minerals suitable for OAE in natural seawater. Of particular importance to understand how much mineral be dissolved before secondary precipitation calcium carbonate (CaCO3) occurs, since CaCO3 reduces atmospheric CO2 uptake potential OAE. Using two types proposed OAE, quick lime (CaO) hydrated (Ca(OH)2), we show both (<63 µm diameter) seawater within few hours. No occurred at saturation state (ΩA) ∼5, but form aragonite above an ΩA value 7. This limit lower than expected typical pseudo-homogeneous precipitation, i.e. presence colloids organic matter. Secondary low (∼ 7) was result heterogeneous onto surfaces, most likely added CaO Ca(OH)2 particles. Most importantly, runaway observed, condition where significantly more total (TA) removed initially added. Such could reduce efficiency ∼ 0.8 mol per mole TA down 0.1 TA. Runaway appears avoidable by dilution below threshold 5, ideally hours additions minimise initial precipitation. Finally, simulations suggest same threshold, amount would 3 times higher 5 ∘C 30 ∘C. The maximum addition also increased equilibrating levels (i.e. pCO2 416 µatm) during addition. allow without inducing using its removal potential.

Language: Английский

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Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches – consequences for durability of CO₂ storage

Biogeosciences, Journal Year: 2023, Volume and Issue: 20(4), P. 781 - 802

Published: Feb. 20, 2023

Abstract. According to modelling studies, ocean alkalinity enhancement (OAE) is one of the proposed carbon dioxide removal (CDR) approaches with large potential, beneficial side effect counteracting acidification. The real-world application OAE, however, remains unclear as most basic assumptions are untested. Before large-scale deployment can be considered, safe and sustainable procedures for addition seawater must identified governance established. One concerns stability when added seawater. surface already supersaturated respect calcite aragonite, an increase in total (TA) together a corresponding shift carbonate chemistry towards higher ion concentrations would result further supersaturation, potentially solid precipitation. Precipitation minerals consumes increases dissolved CO2 seawater, thereby reducing efficiency OAE removal. In order address alkaline solution well fine particulate solids, set six experiments was performed using natural around 2400 µmol kgsw−1. CO2-equilibrated bears lowest risk losing due phase formation if (ΔTA) less than reactive solids cause net loss ΔTA > 600 kgsw−1 (e.g. Mg(OH)2). Commercially available (ultrafine) Ca(OH)2 causes, general, TA tested amounts addition, which has consequences suggested use slurries supplied from ships. rapid excessive Ca(OH)2, exceeding threshold loss, resulted massive (> 20 000 kgsw−1) at cost lower resultant high pH values 9.5. Analysis precipitates indicates aragonite. However, unstable phases formed partially redissolve, indicating that fraction may not permanent, important implications application. Our results indicate instead particles avoid formation, unless via solutions shifts system beyond critical supersaturation levels. To inorganic (DIC) reactor techniques considered. These produce equilibrated prior Differing behaviours materials suggest standardized engineered need developed achieve reactors technologies should avoided.

Language: Английский

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The Availability of Limestone and Other Raw Materials for Ocean Alkalinity Enhancement

Global Biogeochemical Cycles, Journal Year: 2022, Volume and Issue: 36(5)

Published: May 1, 2022

Abstract The work assesses the availability and localizations of different raw materials suitable for ocean alkalinity enhancement (OAE), like limestone, olivine, magnesite brucite, since several billion tons rocky are needed to achieve meaningful results carbon sequestration through OAE. Resources carbonates immense widespread around all continents. Availability pure is still very large (outcrop area 4.1 million km 2 ) not a constraint large‐scale development Outcrops within 10 from coastline below bare ground or scrub/shrub, preferred logistics exploitation, account about 70,000 , could provide 5,000 Gt limestone. These values increase by factor 3 8 50 100 coastline, respectively. Potential resources less easily identifiable geological data, estimated in order few hundred only minor contribution ocean‐based removal strategies. A comparison with current level world extraction mineral also provided. annual production be more than 6.6 deposits scattered world, 9% (around 44 yr −1 ), same magnitude as coal (7.3 ). productions (29 Mt olivine (8.4 brucite (1.5 two orders lower.

Language: Английский

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Limits and CO₂equilibration of near-coast alkalinity enhancement

Biogeosciences, Journal Year: 2023, Volume and Issue: 20(1), P. 27 - 43

Published: Jan. 3, 2023

Abstract. Ocean alkalinity enhancement (OAE) has recently gained attention as a potential method for carbon dioxide removal (CDR) at gigatonne (Gt) scale, with near-coast OAE operations being economically favorable due to proximity mineral and energy sources. In this paper we study critical questions which determine the scale viability of OAE. Which coastal locations are able sustain large flux minimal pH ΩArag (aragonite saturation) changes? What is interference distance between adjacent projects? How much CO2 absorbed per unit added? quickly does induced deficiency equilibrate atmosphere? Choosing relatively conservative constraints on ΔpH or ΔOmega, examine limits using ECCO LLC270 (0.3∘) global circulation model. We find that sustainable rate varies over 1–2 orders magnitude different coasts exhibits complex patterns non-local dependencies vary from region region. general, in areas strong currents enables largest fluxes depending direction these currents, neighboring sites can exhibit far 400 km more. At steady state most regional stretches coastline accommodate order 10s 100s megatonnes negative emissions within 300 coast. conclude near-coastal globally several Gt yr−1 drawdown constraints, if effort spread majority available coastlines. Depending location, diverse set equilibration kinetics, determined by interplay gas exchange surface residence time. Most reach an uptake efficiency plateau 0.6–0.8 mol after 3–4 years, there only slow additional uptake. Regions significant downwelling (e.g., around Iceland) should be avoided deployments, such up half CDR lost bottom waters. The ideal locations, reaching molar ratio 0.8, include North Madagascar, California, Brazil, Peru close Southern Tasmania, Kerguelen Patagonia, where appears occur faster than However, some Hawaii) take significantly longer (up 8–10 years) but still eventually achieve high ratios.

Language: Английский

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Life Cycle Assessment of Coastal Enhanced Weathering for Carbon Dioxide Removal from Air

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(15), P. 6169 - 6178

Published: April 3, 2023

Coastal enhanced weathering (CEW) is a carbon dioxide removal (CDR) approach whereby crushed silicate minerals are spread in coastal zones to be naturally weathered by waves and tidal currents, releasing alkalinity removing atmospheric (CO2). Olivine has been proposed as candidate mineral due its abundance high CO2 uptake potential. A life cycle assessment (LCA) of silt-sized (10 μm) olivine revealed that CEW's life-cycle emissions total environmental footprint, i.e., penalty, amount around 51 kg CO2eq 3.2 Ecopoint (Pt) units per tonne captured CO2, respectively, these will recaptured within few months. Smaller particle sizes dissolve even faster; however, their footprints (e.g., 223 10.6 Pt tCO2–1, for 1 μm olivine), engineering challenges comminution transportation, possible stresses airborne and/or silt pollution) might restrict applicability. Alternatively, larger exhibit lower 14.2 tCO2–1 1.6 1000 olivine) could incorporated zone management schemes, thus possibly crediting CEW with avoided emissions. However, they much slower, requiring 5 37 years before the becomes net negative, respectively. The differences between penalties highlight need using multi-issue impact methods rather than focusing on balances alone. When full profile was considered, it identified fossil fuel-dependent electricity main hotspot, followed nickel releases, which may have large marine ecotoxicity. Results were also sensitive transportation means distance. Renewable energy low-nickel can minimize profile.

Language: Английский

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Coccolithophores and diatoms resilient to ocean alkalinity enhancement: A glimpse of hope?

Science Advances, Journal Year: 2023, Volume and Issue: 9(24)

Published: June 14, 2023

It is increasingly apparent that adequately mitigating anthropogenic climate interference will require ocean carbon dioxide removal (CDR) strategies. Ocean alkalinity enhancement (OAE) an abiotic CDR approach aims to increase the ocean’s CO 2 uptake capacity through dispersal of pulverized mineral or dissolved alkali into surface ocean. However, OAE’s effect on marine biota largely unexplored. Here, we investigate impacts moderate (~700 μmol kg −1 ) and high (~2700 limestone-inspired additions two biogeochemically ecologically important phytoplankton functional group representatives: Emiliania huxleyi (calcium carbonate producer) Chaetoceros sp. (silica producer). The growth rate elemental ratios both taxa showed a neutral response alkalinization. While our results are encouraging, also observed precipitation, which removed nutrients from solution. Our findings offer evaluation biogeochemical physiological responses OAE provide evidence supporting need for continued research how strategies affect ecosystems.

Language: Английский

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