Short-lived Climate Pollutants Research Articles

Quantifying air quality co-benefits to industrial decarbonization: the local Air Emissions Tracking Atlas

IntroductionMany decarbonization technologies have the added co-benefit of reducing short-lived climate pollutants, such as particulate matter (PM), nitrogen oxides (NOx), and sulfur dioxide (SO2), creating a unique opportunity for identifying strategies that promote both climate change solutions and opportunities for air quality improvement. However, stakeholders and decision-makers may struggle to quantify how these co-benefits will impact public health for the communities most affected by industrial air pollution.MethodsTo address this problem, the LOCal Air Emissions Tracking Atlas (LOCAETA) fills a data availability and analysis gap by providing estimated air quality benefits from industrial decarbonization options, such as carbon capture and storage (CCS). These co-benefits are calculated using an algorithm that connects disparate datasets that separately report greenhouse gas emissions and other pollutants at U.S. industrial facilities.ResultsVersion 1.0 of LOCAETA displays the estimated primary PM2.5 emission reduction co-benefits from additional pretreatment equipment for CCS on industrial and power facilities across the state of Louisiana, as well as the potential for VOC and NH3 generation. The emission reductions are presented in the tool alongside facility pollutant emissions information and relevant air quality, environmental, demographic, and public health datasets, such as air toxics cancer risk, satellite and in situ pollutant measurements, and population vulnerability metrics.DiscussionLOCAETA enables regulators, policymakers, environmental justice communities, and industrial and commercial users to compare and contrast quantifiable public health benefits due to air quality impacts from various climate change mitigation strategies using a free and publicly-available tool. Additional pollutant reductions can be calculated using the same methodology and will be available in future versions of the tool.

Socio-environmental Opportunities for Organic Material Management in California's Sustainability Transition.

Contemporary resource management is doubly burdened by high rates of organic material disposal in landfills, generating potent greenhouse gases (GHG), and globally degraded soils, which threaten future food security. Expansion of composting can provide a resilient alternative, by avoiding landfill GHG emissions, returning valuable nutrients to the soil to ensure continued agricultural production, and sequestering carbon while supporting local communities. Recognizing this opportunity, California has set ambitious organics diversion targets in the Short-Lived Climate Pollutant Law (SB1383) which will require significant increases (5 to 8 million tonnes per year) in organic material processing capacity. This paper develops a spatial optimization model to consider how to handle this flow of additional material while achieving myriad social and ecological benefits through compost production. We consider community-based and on-farm facilities alongside centralized, large-scale infrastructure to explore decentralized and diversified alternative futures of composting infrastructure in the state of California. We find using a diversity of facilities would provide opportunity for cost savings while achieving significant emissions reductions of approximately 3.4 ± 1 MMT CO2e and demonstrate that it is possible to incorporate community protection into compost infrastructure planning while meeting economic and environmental objectives.

Need of a Dedicated Programme on Short-Lived Climate Pollutants (SLCP) in South Asia

Need of a Dedicated Programme on Short-Lived Climate Pollutants (SLCP) in South Asia

Climate Change, Air Pollution, and Human Health in the Kruger to Canyons Biosphere Region, South Africa, and Amazonas, Brazil: A Narrative Review

Climate Change, Air Pollution, and Human Health in the Kruger to Canyons Biosphere Region, South Africa, and Amazonas, Brazil: A Narrative Review

Development of ambitious and realistic targets to reduce short-lived climate pollutant emissions in nationally determined contributions: case study for Colombia

Limiting global temperature increases to below 1.5 °C requires reductions in Short-Lived Climate Pollutants (SLCPs), like methane, black carbon, and hydrofluorocarbons (HFCs), which is rarely reflected in targets within Nationally Determined Contributions (NDCs). Colombia’s 2020 NDC is explored as a case study for how Governments can integrate SLCP mitigation targets into climate change commitments. Methane and HFC mitigation contribute approximately 9% of Colombia’s GHG reduction commitment, and a separate target is included to reduce black carbon emissions by 40% by 2030 compared to 2014 levels. These targets are shown to be ambitious, due to the inclusion of a new black carbon target, realistic due to the identification of mitigation measures to achieve them, and additional to CO2 mitigation. Analysis of the planning process establishing these targets emphasises the importance of long-term planning to obtain agreement between coordinating institutions and implementing institutions on the utility of SLCP targets, and capacity-building within national institutions.

단기체류 기후변화 유발물질 중 대류권 오존에 대한 고찰

단기체류 기후변화 유발물질 중 대류권 오존에 대한 고찰

Navigating Legal Culture: A Critical Analysis of India's Legislative Response to Short-Lived Climate Pollutants and Transformative Constitutionalism

Navigating Legal Culture: A Critical Analysis of India's Legislative Response to Short-Lived Climate Pollutants and Transformative Constitutionalism

Impacts of coal use phase-out in China on the atmospheric environment: (2) public health and global radiative forcing

In the second of two companion papers, we quantify the potential ultimate benefits for public health and radiative forcing from the phase-out of coal use in China. With the baseline year of 2015, we estimate that the premature deaths and disability-adjusted life years (DALYs) in China will be reduced by 375,000 persons and 8.90 × 106 years (GEMM model), which is 41.7% and 54.5% of the total number of premature deaths and DALYs caused by PM2.5 from anthropogenic sources, effectively improving the health of the population. The provinces with the most significant decreases in fatalities and disabilities are concentrated in large coal-consuming provinces. Regarding age distribution, the phase-out of coal use will effectively extend the life expectancy of the elderly, especially in the age group of 65–89 years. Health benefits’ growth rate upsurges notably once more than half of coal is phased out. Based on the Parallel Offline Radiative Transfer (PORT) model, the global annual average radiative forcing due to changes in short-lived climate pollutants (SLCPs), including sulfate, black carbon, organic carbon, and O3 associated with the phase-out of coal use, is 0.34 W m−2, -0.048 W m−2, 0.00064 W m−2, and 0.00055 W m−2, respectively. The complete phase-out of coal use in China also reduces the emission of long-lived climate pollutants (LLCPs) and causes negative radiative forcing. Among them, the global annual average radiative forcing of CO2, CH4, and N2O is −0.0073 W m−2, -5.48 × 10−5 W m−2, -1.60 × 10−5 W m−2. If the lifetimes of pollutants are considered, the total global reduction in heat uptake is −2.29 × 107 J m−2 over 100 years, dominated by the decrease of CO2, which will slow the rate of global warming and thus may reduce the probability of extreme weather events. This report will incentivize relevant policymakers to remove coal significantly to achieve carbon neutrality.

Production of a Database on Short-Lived Climate Pollutants (SLCP) and the Elaboration of Projection Scenarios of these Emissions Using the LEAP Software - The Case of Morocco

Short-lived climate pollutants (SLCPs) have significant effects on climate, human health, and the environment. In Morocco, steps are being taken to reduce SLCP emissions, but effective policymaking requires a thorough understanding of emission sources and trends. In this paper, we present a study on the production of a database on SLCP emissions in Morocco, as well as the development of scenarios to project these emissions using LEAP software. The results of this analysis allow us to better understand the emissions sources and evaluate the impact of different emission reduction policies.

Modelling large-scale hydrogen uptake in the Mexican refinery and power sectors

Due to the emissions reduction commitments that Mexico compromised in the Paris Agreement, several clean fuel and renewable energy technologies need to penetrate the market to accomplish the environmental goals. Therefore, there is a need to develop achievable and realistic policies for such technologies to ease the decision-making on national energy strategies. Several countries are starting to develop large-scale green hydrogen production projects to reduce the carbon footprint of the multiple sectors within the country. The conversion sectors, namely power and refinery, are fundamental sectors to decarbonise due to their energy supply role. Nowadays, the highest energy consumables of the country are hydrocarbons (more than 90%) causing a particular challenge for deep decarbonisation. The purpose of this study is to use a multi-regional energy system model of Mexico to analyse a decarbonisation scenario in line with the latest National Energy System Development Program. Results show that if the country wants to succeed in reducing 22% of its GHG emissions and 51% of its short-lived climate pollutants emissions, green hydrogen could play a role in power generation in regions with higher energy demand growth rates. These results show, regarding the power sector, that H2 could represent 13.8 GW or 5.1% of the total installed capacity by 2050, while for the refinery sector H2 could reach a capacity of 157 PJ/y, which is around 31.8% of the total share, and it is mainly driven by the increasing demands of the transport, industry, and power sectors. Nevertheless, as oil would still represent the largest energy commodity, CCS technologies would have to be deployed for new and retrofitted refinery facilities.

Provenance of Aerosol Black Carbon over Northeast Indian Ocean and South China Sea and Implications for Oceanic Black Carbon Cycling.

Aerosol black carbon (BC) is a short-lived climate pollutant. The poorly constrained provenance of tropical marine aerosol BC hinders the mechanistic understanding of extreme climate events and oceanic carbon cycling. Here, we collected PM2.5 samples during research cruise NORC2016-10 through South China Sea (SCS) and Northeast Indian Ocean (NEIO) and measured the dual-carbon isotope compositions (δ13C-Δ14C) of BC using hydrogen pyrolysis technique. Aerosol BC exhibits six different δ13C-Δ14C isotopic spaces (i.e., isotope provinces). Liquid fossil fuel combustion, from shipping emissions and adjacent land, is the predominant source of BC over isotope provinces "SCS close to Chinese Mainland" (53.5%), "Malacca Strait" (53.4%), and "Open NEIO" (40.7%). C3 biomass burning is the major contributor to BC over isotope provinces "NEIO close to Southeast Asia" (55.8%), "Open NEIO" (41.3%), and "Open SCS" (40.0%). Coal combustion and C4 biomass burning show higher contributions to BC over "Sunda Strait" and "Open SCS" than the others. Overall, NEIO near the Bay of Bengal, Malacca Strait, and north SCS are three hot spots of fossil fuel-derived BC; the first two areas are also hot spots of biomass-derived BC. The comparable δ13C-Δ14C between BC in aerosol and dissolved BC in surface seawater may suggest atmospheric BC deposition as a potential source of oceanic dissolved BC.

Influence of biomass burning on ozone levels in the Megalopolis of Central Mexico during the COVID-19 lockdown

The massive reductions in anthropogenic emissions resulting from the COVID-19 lockdown provided a unique opportunity to evaluate the effect of mitigation measures aiming to abate air pollution. In Mexico, the total lockdown period took place during the dry-hot season when biomass burning activity is enhanced. Here, we investigate the role of biomass burning emissions on regional ozone levels in the Megalopolis of Central Mexico. The studied period covers the lockdown phases 2 and 3, and the first month of the New Normal.We applied a factor separation technique and process analysis to estimate the pure and synergistic contributions of emission reductions under lockdown and that from biomass burning to daily ozone maximum concentrations in 7 metropolitan areas of different states in the Megalopolis. The results revealed that biomass burning plumes likely masked the effect of massive reductions from mobile emissions, impacted the PBL development during phase 3 and favored transition and mixed NOx-limited and VOC-limited regional regimes. This contributed to increased ozone production in the middle to lower PBL by changing the regional background levels which potentially could bias high ozone production efficiency estimations.Given the Megalopolis contribution to economic and societal development at national scale, our study suggests that ozone mitigation measures during the dry-hot season targeting mainly mobile emissions will likely be offset by biomass burning plumes. A regional and synergic policy aiming to control biomass burning would help to reduce the occurrence of high ozone levels in Central Mexico with the co-benefit of tackling short-lived climate pollutants.

Metrics for the emissions of F-gas refrigerants

This paper examines the metrics used to account for the contribution to global warming from fluorinated gases (f-gases) mainly used as refrigerants for cooling. F-gases are key to climate mitigation discussion as they a) are critical to delivering the surging demand for air conditioners which is expected to triple by 2050, b) have strong Global Warming Potential (GWP) as high as 12,000 kgCO2-eq (for e.g., HFC-23) and c) are targeted by international policy agreements such as the Montreal Protocol and Kigali Amendment. F-gases exacerbate atmospheric warming when leaked from cooling equipment, or during other phases of their life cycle. Thus far, the way these gases impact global warming is mostly reported based on their CO2-equivalent emissions with a time horizon of 100 years. However, the problem is that f-gases have significantly different lifespans and the GWP100 does not account for these variations. The debate on metrics to account for warming of other short-lived climate pollutants (SLCP), such as methane is already ongoing. Here, we provide the first step to open such debate for short-lived f-gases. We address this, first, with a critical review of the available metrics for carbon foot-printing of f-gases and present a gap analysis between the existing carbon foot printing metrics and the need to better understand warming from f-gases. Second, we use an atmospheric model to illustrate how the incumbent metric (CO2-equivalent calculated using GWP100), misrepresent the warming of an exemplary f-gas refrigerant (HFC-134a). The model outputs novel profiles of atmospheric concentration, radiative forcing, and temperature, in three scenarios. Scenario A models the response to a positive step change in emissions of the HFC, while Scenario B is the inverse. Scenario C models a reduction of 85% by 2036 of emissions according to targets for high-emitting countries set in the Kigali Amendment. The modelling results evidence that the commonly used CO2-equivalent with its GWP100 does not represent the atmospheric responses, and particularly the warming of the exemplary short-lived HFC. Through the literature review, however, we identify many other metrics available that could be applied for f-gases, and particularly GWP* is recommended to examine in future works. In summary, the paper offers insights into which metrics can best help to identify the effects of f-gases in terms of reducing global warming in a rapid timeframe, and how CO2-equivalents should not be used as proxy for atmospheric warming in policy discussions.

Methane emissions from California dairies estimated using novel climate metric Global Warming Potential Star show improved agreement with modeled warming dynamics

IntroductionCarbon dioxide (CO2) and methane (CH4) are two of the primary greenhouse gases (GHG) responsible for global warming. The “stock gas” CO2 accumulates in the atmosphere even if rates of CO2 emission decline. In contrast, the “flow gas” CH4 has an e-folding time of about 12 years and is removed from the atmosphere in a relatively short period of time. The climate impacts of cumulative pollutants such as CO2 and short-lived climate pollutants (SLCP) such as CH4 are often compared using Global Warming Potential (GWP), a metric that converts non-CO2 GHG into CO2-equivalent emissions. However, GWP has been criticized for overestimating the heating effects of declining SLCP emissions and conversely underestimating the heating impact of increasing SLCP emissions. Accurate quantification of the temperature effects of different CH4 emissions scenarios is particularly important to fully understanding the climate impacts of animal agriculture, whose GHG emissions are dominated by CH4.MethodsA modified GWP metric known as Global Warming Potential Star (GWP*) has been developed to directly quantify the relationship between SLCP emissions and temperature change, which GWP cannot do. In this California dairy sector case study, we contrasted GWP- versus GWP*-based estimates of historical warming dynamics of enteric and manure CH4 from lactating dairy cattle. We predicted future dairy CH4 emissions under business-as-usual and reduction scenarios and modeled the warming effects of these various emission scenarios.ResultsWe found that average CO2 warming equivalent emissions given by GWP* were greater than those given by GWP under increasing annual CH4 emissions rates, but were lower under decreasing CH4 emissions rates. We also found that cumulative CO2 warming equivalent emissions given by GWP* matched modeled warming driven by decreasing CH4 emissions more accurately than those given by GWP.DiscussionThese results suggest that GWP* may provide a more accurate tool for quantifying SLCP emissions in temperature goal and emissions reduction-specific policy contexts.

Present global warming: a justifiable and stable metric for evaluating short-lived climate pollutants

The impacts of short-lived climate pollutants (SLCPs) such as methane are typically described using metrics that compare their climate impacts to carbon dioxide’s climate impact. The metrics consider a climate pollutant’s atmospheric heat-trapping effectiveness and atmospheric lifetime. Here we introduce an alternative metric called the Present Global Warming (PGW), which uses economic exponential discount modelling to characterize short-term and long-term effects simultaneously, resulting in a justifiable, familiar, and stable metric for evaluating SLCPs. We recommend quantifying the climate impacts of methane emissions using 2.5% annual discounting—consistent with the discount rates recently proposed in academic work and traditionally used in climate policy—corresponding to methane PGW2.5% = 50. In this context, one ton of emitted methane has the same climate impact as 50 tons of emitted carbon dioxide.

Identifying cross-sectoral policy synergies for decarbonization: Towards short-lived climate pollutant mitigation action in Costa Rica

Decarbonization is a process that transforms economies to lower greenhouse gas (GHG) emissions per unit of economic output, aiming towards net-zero GHG emissions. This process could also reduce short-lived climate pollutant (SLCP) emissions, including black carbon and methane. They have relatively short atmospheric lifetimes but have large radiative forcing and impact human health. Therefore, reducing SLCPs can improve air pollution and help mitigate climate change. Costa Rica was one of the first countries to have a decarbonization plan, and many others have stated their goal to reach net-zero emissions by around mid-century. However, reducing SLCP emissions as an economy decarbonizes is not guaranteed, and few examples in the literature have assessed how decarbonization impacts SLCPs. This paper estimates the SLCP emission reductions from Costa Rica's decarbonization plan. Through a value chain analysis and the identification of implementation barriers, the paper also evaluates which policy instruments can advance SLCP mitigation in multiple sectors, creating implementation synergy. We find that mitigation measures, by 2050, in the transport, agricultural, solid waste, and industrial sectors avoid 25.2 kt of black carbon emissions (23 times the 2018 emissions) and 2167 kt of methane (15 times the 2018 emissions). However, the country faces financial and governance challenges in each sector that will need overcoming to implement the intended mitigation measures. We identify a comprehensive environmental tax reform, the overhauling of urban regulatory plans, the strengthening of institutional capabilities, and low-carbon investment with favorable financing as crucial cross-sectoral policy synergies that will advance the implementation of SLCP mitigation.

4. Arctic

Regional initiatives relevant to Arctic environmental protection in the past year occurred mainly through the Arctic Council. The twelfth ministerial meeting of the Arctic Council was held on 20 May in Reykjavík, Iceland, and the Council’s six working groups continued their cooperative projects and publications. Documentation from the ministerial meeting and working group meetings may be found on the Council’s website (<http://www.arctic-council.org>). International activities of further note occurred in other venues. These activities included working through the International Maritime Organization (IMO) to ban the carriage for use as fuel of heavy fuel oil by ships in Arctic waters; advancing implementation of the Agreement to Prevent Unregulated High Seas Fisheries in the Central Arctic Ocean; promoting environmental cooperation through the Barents Euro-Arctic Council; and convening the fourteenth Conference of Parliamentarians of the Arctic Region. The Reykjavík Declaration 2021, issued on the occasion of the twelfth ministerial meeting, gave considerable attention to climate change. The declaration expresses utmost concern regarding the Arctic warming at a rate of three times the global average over the past fifty years and recognizes that the deposition of black carbon in the Arctic accelerates the melting of snow and ice. The declaration reiterates the need for enhanced action to meet the long-term temperature goal and implementation of the Paris Agreement by reducing emissions of greenhouse gases and short-lived climate pollutants. The declaration approves the report, Expert Group on Black Carbon and Methane: Summary of Progress and Recommendations 2021, supports the collective and aspirational goal to reduce black carbon emissions by 25–33 percent below 2013 levels by 2025, and strongly encourages observer states to commit to similar reduction goals. The need for additional action and measures to significantly reduce methane emissions was noted.

Integration of Short-Lived Climate Pollutant and air pollutant mitigation in nationally determined contributions

ABSTRACT Limiting global temperature increases to 1.5 °C while respecting ‘the right to health’ requires substantial reductions in Short-Lived Climate Pollutants (SLCPs), including methane, black carbon and hydrofluorocarbons, and co-emitted air pollutants. This study evaluates the inclusion of SLCP and air pollutant mitigation within Nationally Determined Contributions (NDCs) that were submitted between 2015 and 2022. Between pre- and post-2020 NDCs, explicit reference to SLCPs and air pollutant mitigation as priorities more than doubled, indicating a rise in policy attention to these pollutants. There was also a large increase in the percentage of countries including methane and HFCs within the scope of their overall GHG reduction targets, and three countries include explicit black carbon reduction targets. With respect to policy, there was a 45% increase in the number of specific mitigation measures included in NDCs post-2020. Hence, the number of countries with implicit reductions in SLCPs and other air pollutants covered in their NDCs is now also substantially larger compared to pre-2020, due to greater inclusion of mitigation measures that reduce SLCPs and air pollutants alongside (other) GHGs.

A simulation study on the climatic responses to short-lived climate pollutants changes from the pre-industrial era to the present

Short-lived climate pollutants (SLCPs) including methane, tropospheric ozone, and black carbon in this work, is a set of compounds with shorter lifetimes than carbon dioxide (CO2) and can cause warming effect on climate. Here, the effective radiative forcing (ERF) is estimated by using an online aerosol–climate model (BCC_AGCM2.0_CUACE/Aero); then the climate responses to SLCPs concentration changes from the pre-industrial era to the present (1850–2010) are estimated. The global annual mean ERF of SLCPs was estimated to be 0.99 [0.79–1.20] W m−2, and led to warming effects over most parts of the globe, with the warming center (about 1.0 K increase) being located in the mid-high latitudes of the Northern Hemisphere (NH) and the ocean around Antarctica. The changes in annual mean surface air temperature (SAT) caused by SLCPs changes were more prominent in the NH [0.78 (0.62–0.94) K] than in the Southern Hemisphere [0.62 (0.45–0.74) K], and the global annual mean value is 0.70 K. By looking at other variable responses, we found that precipitation had been increased by about 0.10 mm d−1 in mid- and high-latitudes and decreased by about 0.20 mm d−1 in subtropical regions, with the global annual mean value of 0.02 mm d−1. Changes in SLCPs also influenced atmospheric circulation change, a northward shift in the Intertropical Convergence Zone was induced due to the interhemispheric asymmetry in SAT. However, it is found in this work that SLCPs changes had little effect on global average cloud cover, whereas the local cloud cover changes could not be ignored, low cloud cover increase by about 2.5% over high latitudes in the NH and the ribbon area near 60°S, and high cloud cover increased by more than 2.0% over northern Africa and the Indian Ocean. Finally, we compared the ERFs and global and regional warming effects of SLCPs with those induced by CO2 changes. From 1850 to the present, the ERF of SLCPs was equivalent to 66%, 83%, and 50% of that of CO2 in global, NH, and SH mean, respectively. The increases in SAT caused by SLCPs were 43% and 55% of those by CO2 over the globe and China, respectively.

Multi-type emission factors quantification of black carbon from agricultural machinery based on the whole tillage processes in China

Black carbon (BC), as one of the short-lived climate pollutants, is becoming more prominent contribution from non-road mobile source, especially for agricultural machinery (AM) in China. However, the understanding of BC emissions from AM is still not clear, and the BC emission factors (EFs) are also limited. In this study, we conducted real-world measurements on twenty AM to investigate the instantaneous BC emission characteristics and quantify BC EFs under the whole tillage processes. We find the instantaneous BC emissions and fuel consumptions are obvious differences and present good synchronization under different tillage processes. Multi-type (CO2-, fuel-, distance-, time-, and area-based) EFs of BC are developed, which are significantly affected by different tillage processes and emission standards of the used AM. While AM conducting rotary tillage, ploughing, harvest corn and harvest wheat on the same area of land, total BC emissions by using the China III emission standard AM will be reduced by 56%, 36%, 88%, and 87% than those by using China II emission standard AM, respectively. Furthermore, for corn and wheat production under the whole tillage processes, BC EFs are 16.90 (6.03–39.12) g/hm2 and 18.18 (5.91–38.69) g/hm2, CO2 EFs are 112.64 (72.07–195.98) g/hm2 and 103.72 (71.47–167.02) g/hm2, respectively. We estimate the BC and CO2 emissions from wheat and corn productions based on the average area-based EFs. The large fluctuation ranges of BC and CO2 emissions in different tillage processes and the whole processes can reflect that the use of AM in China is uneven. It also indicates that there is a large space for BC and CO2 emission reduction and optimization. Therefore, more attention should be paid to the control of BC and CO2 emissions from AM. We believe that the recommended multi-type EFs are applicable for the quantification of BC emissions from AM in China and other countries.