From EBIT to SEBIT(Sustainable EBIT):Sustainable Performance Accounting(SPA)Using the Example of CO_(2) Accounting

Corporate sustainability reporting has become increasingly important in recent years.However,conventional approaches reach their limits when it comes to quantifying and measuring the actual sustainability performance of a company.This article presents a new approach:Sustainable Performance Accounting(SPA),which is based on an extension of bookkeeping by including ESG bookkeeping.SPA enables companies to systematically measure and manage their sustainability performance.The article provides an overview of the basics of SPA methodology and uses a comprehensive example showing how SPA can be implemented in practice.The article is aimed at interested readers from science and practice as well as decision-makers who are interested in future-oriented sustainability reporting.

Comparing the climate change mitigation potentials of alternative land uses:Crops for biofuels or biochar vs.natural regrowth

Using biomass from dedicated crops for energy production and natural vegetation regrowth are key elements in future climate change mitigation scenarios.However,there are still uncertainties about the mitigation potentials that can be achieved by the different land-based systems and how they perform relative to each other.In this study,we use harmonized future land use datasets to identify global land areas dedicated to second generation bioenergy crop production in 2050 under different climate scenarios.We then assess the global climate change mitigation potentials of using biomass for producing bioethanol with(BECCS)or without carbon capture and storage,biochar,or a synthetic fuel(e-methanol).For the latter,the electricity required to produce hydrogen for e-methanol synthesis is sourced from either wind power or the projected average electricity mix in 2050.Mitigation potential from natural regrowth on the identified land is also quantified.For all the cases,we modelled emissions of greenhouse gases from the life-cycle stages and use parameterized models to estimate local biomass growth rates.The identified land areas range from 1.95 to 13.8 million hectares and can provide from 30 to 178 mega ton(Mt)dry biomass annually from dedicated crops.Climate change mitigation potentials range from 11 to 257 MtCO_(2)-eq.yr^(−1),depending on technological option and land availability.The largest mitigation is delivered by BECCS,but e-methanol can achieve similar findings when hydrogen is sourced from wind power.If hydrogen is produced from grid electricity,e-methanol can result in net positive emissions.E-methanol can also deliver more final energy than bioethanol(4.04 vs.1.27 EJ yr^(−1)).Natural vegetation regrowth can generally achieve higher mitigation than bioethanol,but less than biochar.An optimal combination of BECCS and natural vegetation regrowth can achieve a larger mitigation,up to 281 MtCO_(2)-eq.yr^(−1),indicating that integrated solutions can help to achieve successful land management strategies for climate change mitigation.

Modified Ramsey Rule, Optimal Carbon Tax and Economic Growth

In contrast to the overlapping-generations model, it is allowable to discount the future utility in a dynasty model without the ethical difficulty related to intergenerational conflicts. Much precedent research uses Ramsey-type optimal growth theory in order to estimate the social discount rate. However, one must note that almost all the formulations neglect the existence of negative intertemporal externalities. This problem is vital when one analyzes the global warming problem mainly caused by the excess concentration of carbon dioxide (CO2). This is because an adjoining effect of capital accumulation exists besides the improvement of product capacity, which is reflected in the rate of interest (or equivalently, the marginal productivity of capital). That is, one cannot neglect a negative externality to the future productivity that originates from the excess emissions of CO2. Accordingly, following the optimal growth theory, the effective social discount rate should be heightened by a proportional carbon tax to suppress future excess consumption/ emissions than in the case of the existing analyses, which exclude such an intertemporal external diseconomy.

Response of ocean acidification to atmospheric carbon dioxide removal

Artificial CO_(2)removal from the atmosphere(also referred to as negative CO_(2)emissions)has been proposed as a potential means to counteract anthropogenic climate change.Here we use an Earth system model to examine the response of ocean acidification to idealized atmospheric CO_(2)removal scenarios.In our simulations,atmospheric CO_(2)is assumed to increase at a rate of 1%per year to four times its pre-industrial value and then decreases to the pre-industrial level at a rate of 0.5%,1%,2%per year,respectively.Our results show that the annual mean state of surface ocean carbonate chemistry fields including hydrogen ion concentration([H^(+)]),pH and aragonite saturation state respond quickly to removal of atmospheric CO_(2).However,the change of seasonal cycle in carbonate chemistry lags behind the decline in atmospheric CO_(2).When CO_(2)returns to the pre-industrial level,over some parts of the ocean,relative to the pre-industrial state,the seasonal amplitude of carbonate chemistry fields is substantially larger.Simulation results also show that changes in deep ocean carbonate chemistry substantially lag behind atmospheric CO_(2)change.When CO_(2)returns to its pre-industrial value,the whole-ocean acidity measured by[H^(+)]is 15%-18%larger than the pre-industrial level,depending on the rate of CO_(2)decrease.Our study demonstrates that even if atmospheric CO_(2)can be lowered in the future as a result of net negative CO_(2)emissions,the recovery of some aspects of ocean acidification would take decades to centuries,which would have important implications for the resilience of marine ecosystems.

Eco-engineering approaches for ocean negative carbon emission

The goal of achieving carbon neutrality in the next 30-40 years is approaching worldwide consensus and requires coordinated efforts to combat the increasing threat of climate change.Two main sets of actions have been proposed to address this grand goal.One is to reduce anthropogenic CO2emissions to the atmosphere,and the other is to increase carbon sinks or negative emissions,i.e.,removing CO2from the atmosphere.Here we advocate eco-engineering approaches for ocean negative carbon emission(ONCE),aiming to enhance carbon sinks in the marine environment.An international program is being established to promote coordinated efforts in developing ONCE-relevant strategies and methodologies,taking into consideration ecological/biogeochemical processes and mechanisms related to different forms of carbon(inorganic/organic,biotic/abiotic,particulate/dissolved) for sequestration.We focus on marine ecosystem-based approaches and pay special attention to mechanisms that require transformative research,including those elucidating interactions between the biological pump(BP),the microbial carbon pump(MCP),and microbially induced carbonate precipitation(MICP).Eutrophic estuaries,hypoxic and anoxic waters,coral reef ecosystems,as well as aquaculture areas are particularly considered in the context of efforts to increase their capacity as carbon sinks.ONCE approaches are thus expected to be beneficial for both carbon sequestration and alleviation of environmental stresses.

Fight for carbon neutrality with state-of-the-art negative carbon emission technologies

After the Industrial Revolution,the ever-increasing atmospheric CO_(2)concentration has resulted in significant problems for human beings.Nearly all countries in the world are actively taking measures to fight for carbon neutrality.In recent years,negative carbon emission technologies have attracted much attention due to their ability to reduce or recycle excess CO_(2)in the atmosphere.This review summarizes the state-of-the-art negative carbon emission technologies,from the artificial enhancement of natural carbon sink technology to the physical,chemical,or biological methods for carbon capture,as well as CO_(2)utilization and conversion.Finally,we expound on the challenges and outlook for improving negative carbon emission technology to accelerate the pace of achieving carbon neutrality.

Biomass residue to carbon dioxide removal:quantifying the global impact of biochar

The Climate Change Conference of Parties(COP)21 in December 2015 established Nationally Determined Contributions toward reduction of greenhouse gas emissions.In the years since COP21,it has become increasingly evident that carbon dioxide removal(CDR)technologies must be deployed immediately to stabilize concentration of atmospheric greenhouse gases and avoid major climate change impacts.Biochar is a carbon-rich material formed by high-temperature conversion of biomass under reduced oxygen conditions,and its production is one of few established CDR methods that can be deployed at a scale large enough to counteract effects of climate change within the next decade.Here we provide a generalized framework for quantifying the potential contribution biochar can make toward achieving national carbon emissions reduction goals,assuming use of only sustainably supplied biomass,i.e.,residues from existing agricultural,livestock,forestry and wastewater treatment operations.Our results illustrate the significant role biochar can play in world-wide CDR strategies,with carbon dioxide removal potential of 6.23±0.24%of total GHG emissions in the 155 countries covered based on 2020 data over a 100-year timeframe,and more than 10%of national emissions in 28 countries.Concentrated regions of high biochar carbon dioxide removal potential relative to national emissions were identified in South America,northwestern Africa and eastern Europe.

SEQUESTERING ORGANIC CARBON IN SOILS THROUGH LAND USE CHANGE AND AGRICULTURAL PRACTICES:A REVIEW

Climate change vigorously threats human livelihoods,places and biodiversity.To lock atmospheric CO_(2)up through biological,chemical and physical processes is one of the pathways to mitigate climate change.Agricultural soils have a significant carbon sink capacity.Soil carbon sequestration(SCS)can be accelerated through appropriate changes in land use and agricultural practices.There have been various meta-analyses performed by combining data sets to interpret the influences of some methods on SCS rates or stocks.The objectives of this study were:(1)to update SCS capacity with different landbased techniques based on the latest publications,and(2)to discuss complexity to assess the impacts of the techniques on soil carbon accumulation.This review shows that afforestation and reforestation are slow processes but have great potential for improving SCS.Among agricultural practices,adding organic matter is an efficient way to sequester carbon in soils.Any practice that helps plant increase C fixation can increase soil carbon stock by increasing residues,dead root material and root exudates.Among the improved livestock grazing management practices,reseeding grasses seems to have the highest SCS rate.

Establishment of green graphite industry:Graphite from biomass and its various applications

Resource-and energy-efficient biomass exploitation for green graphite production is one of the most effective strategies for satisfying graphite demand while minimizing energy consumption and carbon emissions.This study investigated green graphite production from biomass waste and its applications to establish a green graphite industry.Biomass pyrolysis and catalytic graphitization of biochar were studied first to produce green graphite.The optimized green graphite exhibited a reversible capacity of 264 mA h/g and 97%capacity retention over 100 cycles in a half-cell.Green graphite electrodes with a resistivity lower than 5μΩm were fabricated by using organic fraction bio-oil as a green binder.Other green graphite applications,including printing,conductive printing,pencils,and refractories,were also achieved.The overall process of graphite anode and electrode synthesis from biomass waste and short-rotation energy crops was modeled.Approx.95 kg of battery graphite or 109 kg of metallurgical graphite electrodes can be produced per ton of biomass with low primary energy consumption and carbon footprint.Prominently,the modeling result and life cycle assessment demonstrated that,for the production of battery graphite from biomass waste,net-negative-CO_(2)emissions(−0.57 kg CO_(2)-eq/kg graphite powders)with net-negative-primary energy consumption(−28.31 MJ/kg graphite powders)was achieved.

A green route for hydrogen production from alkaline thermal treatment(ATT)of biomass with carbon storage

Hydrogen,a green energy carrier,is one of the most promising energy sources.However,it is currently mainly produced from depleting fossil fuels with high carbon emissions,which has serious negative effects on the economy and environment.To address this issue,sustainable hydrogen production from bio-energy with carbon capture and storage(HyBECCS)is an ideal technology to reduce global carbon emissions while meeting energy demand.This review presents an overview of the latest progress in alkaline thermal treatment(ATT)of biomass for hydrogen production with carbon storage,especially focusing on the technical characteristics and related challenges from an industrial application perspective.Additionally,the roles of alkali and catalyst in the ATT process are critically discussed,and several aspects that have great influences on the ATT process,such as biomass types,reaction parameters,and reactors,are expounded.Finally,the potential solutions to the general challenges and obstacles to the future industrial-scale application of ATT of biomass for hydrogen production are proposed.

Achievements,challenges and global implications of China’s carbon neutral pledge

China has been committed to achieving carbon neutrality by 2060.China’s pledge of carbon neutrality will play an essential role in galvanising global climate action,which has been largely deferred by the Covid-19 pandemic.China’s carbon neutrality could reduce global warming by approximately 0.2–0.3°C and save around 1.8 million people from premature death due to air pollution.Along with domestic benefits,China’s pledge of carbon neutrality is a“game-changer”for global climate action and can inspire other large carbon emitters to contribute actively to mitigate carbon emissions,particularly countries along the Belt and Road Initiative(BRI)routes.In order to achieve carbon neutrality by 2060,it is necessary to decarbonise all sectors in China,including energy,industry,transportation,construction,and agriculture.However,this transition will be very challenging,because major technological breakthroughs and large-scale investments are required.Strong policies and implementation plans are essential,including sustainable demand,decarbonizing electricity,electrification,fuel switching,and negative emissions.In particular,if China can peak carbon emissions earlier,it can lower the costs of the carbon neutral transition and make it easier to do so over a longer time horizon.China’s pledge of carbon neutrality by 2060 and recent pledges at the 26th UN Climate Change Conference of the Parties(COP26)are significant contributions and critical steps for global climate action.However,countries worldwide need to achieve carbon neutrality to keep the global temperature from growing beyond the level that will cause catastrophic damages globally.