Climate Change Mitigation Policies Research Articles

Underestimation of Thermogenic Methane Emissions in New York City.

Recent studies have shown that methane emissions are underestimated by inventories in many US urban areas. This has important implications for climate change mitigation policy at the city, state, and national levels. Uncertainty in both the spatial distribution and sectoral allocation of urban emissions can limit the ability of policy makers to develop appropriately focused emission reduction strategies. Top-down emission estimates based on atmospheric greenhouse gas measurements can help to improve inventories and inform policy decisions. This study presents a new high-resolution (0.02 × 0.02°) methane emission inventory for New York City and its surrounding area, constructed using the latest activity data, emission factors, and spatial proxies. The new high-resolution inventory estimates of methane emissions for the New York-Newark urban area are 1.3 times larger than those for the gridded Environmental Protection Agency inventory. We used aircraft mole fraction measurements from nine research flights to optimize the high-resolution inventory emissions within a Bayesian inversion. These sectorally optimized emissions show that the high-resolution inventory still significantly underestimates methane emissions within the New York-Newark urban area, primarily because it underestimates emissions from thermogenic sources (by a factor of 2.3). This suggests that there remains a gap in our process-based understanding of urban methane emissions.

The largest European forest carbon sinks are in the Dinaric Alps old-growth forests: comparison of direct measurements and standardised approaches

BackgroundCarbon (C) sink and stock are among the most important ecosystem services provided by forests in climate change mitigation policies. In this context, old-growth forests constitute an essential reference point for the development of close-to-nature silviculture, including C management techniques. Despite their small extent in Europe, temperate old-growth forests are assumed to be among the most prominent in terms of biomass and C stored. However, monitoring and reporting of C stocks is still poorly understood. To better understand the C stock amount and distribution in temperate old-growth forests, we estimated the C stock of two old-growth stands in the Dinaric Alps applying different assessment methods, including direct and indirect approaches (e.g., field measurements and allometric equations vs. IPCC standard methods). This paper presents the quantification and the distribution of C across the five main forest C pools (i.e., aboveground, belowground, deadwood, litter and soil) in the study areas and the differences between the applied methods.ResultsWe report a very prominent C stock in both study areas (507 Mg C ha− 1), concentrated in a few large trees (36% of C in 5% of trees). Moreover, we found significant differences in C stock estimation between direct and indirect methods. Indeed, the latter tended to underestimate or overestimate depending on the pool considered.ConclusionsComparison of our results with previous studies and data collected in European forests highlights the prominence of temperate forests, among which the Dinaric Alps old-growth forests are the largest. These findings provide an important benchmark for the development of future approaches to the management of the European temperate forests. However, further and deeper research on C stock and fluxes in old-growth stands is of prime importance to understand the potential and limits of the climate mitigation role of forests.

Eco-efficient asphalt recycling for urban slow mobility

Cycling infrastructures contribute to advancing zero-impact transport systems, aligning with the European Commission’s proactive climate change mitigation policies. This paper explores the potential of innovative and sustainable pavements for cycling paths with mixtures composed of road-milling materials. This investigation involves low-environmental-impact bituminous-based mixtures differing from recipe, mixing method, and laying. Up to 100% secondary aggregates are used as alternative materials to design the Grande Raccordo Anulare delle Biciclette (GRAB), a 44-km cycling ring in Rome. According to the European standard EN 15804, their “from cradle to gate” life cycle analysis allows a comprehensive assessment and comparison of the environmental impact. Core and additional environmental impact categories and resource use indicators were quantified using primary data from asphalt producers and secondary data from the Ecoinvent database in the SimaPro software. Within the H2020 InfraROB project (grant agreement no. 955337), which aims at enhancing road infrastructure integrity, performance, and safety through autonomous robotic solutions and modularization, experimental sections have been constructed using a cold-mixed asphalt composed entirely of recycled asphalt and a rejuvenating additive. The results underscore the potential of the examined low-impact approach in conserving Earth’s resources, ensuring long-lasting infrastructure for vulnerable urban populations and fostering sustainable environmental management.

Navigating climate change complexity and deep uncertainty: approach for building socio-ecological resilience using qualitative dynamic simulation

The consequences of climate change on different sectors of society are interrelated. The threats posed by rising global temperatures, intensifying extreme weather events, and shifting climatic patterns are becoming increasingly evident all around the world. Policymakers face the daunting task of assessing climate change risks, encompassing impacts and response strategies, to guide sustainability transformations. In this study, we introduce a four-step qualitative Decision Making Under Deep Uncertainty (DMDU) approach in the context of Climate Change Impact Assessments (CCIA). Our goal is to enhance the integration of CCIA into spatial planning, particularly in the Global South, using qualitative system dynamics simulation. Emphasizing the value of qualitative DMDU, we explore vulnerability and resilience through a lens of multi-sectoral and multi-scalar socio-ecological processes. We exemplify our approach by applying CCIA to the coastal zone of Yucatán, Mexico, accounting for social and environmental heterogeneity across the four Regions in which it is administered. Results identify the optimal allocation of climate change mitigation and adaptation policies to address specified resilience in each Region, all of which are required to achieve the overall resilience of the coastal zone. We argue that our qualitative DMDU approach provides an analytical platform to address the trade-offs inherent in the ranking of multiple vulnerabilities related to achieving general resilience.

Progress and challenges in remotely sensed terrestrial carbon fluxes

ABSTRACT Accurate evaluation of terrestrial carbon balance is essential for designing climate change mitigation policies, and capabilities of remote sensing techniques in monitoring carbon fluxes are widely recognized for their great contributions to regional and global carbon budget accounting. In this review, we synthesized satellite-based data and methodologies to estimate the main flux components of terrestrial carbon balance and their uncertainties over the past two decades. The global gross primary production (GPP) during the period 2001–2022 is 134 ± 14 PgC yr−1, and nearly half of them occurs in tropical forest regions such as South America and Africa. Less than 2% of global GPP is converted into a net carbon sink of 2.28 ± 1.12 PgC yr−1 using satellite-based atmospheric inversion during 2015–2020, and this sink is comparable to the stock change-based estimate (2.49 PgC yr−1) but twice as large as model-based estimate (1.08 ± 0.78 PgC yr−1). By decomposing satellite-derived net carbon balance into different terms including satellite-derived carbon emissions from land-use change and wildfires (3.55 PgC yr−1), we inferred that ~ 43% of global GPP would be respired through soil microbes (57.1 PgC yr−1), but which is higher than the previous bottom-up estimate (39–46 PgC yr−1). We then propose that an accurate remote sensing of terrestrial carbon balance requires to enhance representations of photosynthetic responses to rising CO2 and disturbances, develop satellite-constrained belowground carbon dynamics and separate natural fluxes from anthropogenic CO2 emissions, by integrating multi-source satellite sensors in orbit, revolutionized remote sensing capabilities with focused field campaigns in data-scarce regions.

Quantifying methane emissions from United States landfills.

Methane emissions from solid waste may represent a substantial fraction of the global anthropogenic budget, but few comprehensive studies exist to assess inventory assumptions. We quantified emissions at hundreds of large landfills across 18 states in the United States between 2016 and 2022 using airborne imaging spectrometers. Spanning 20% of open United States landfills, this represents the most systematic measurement-based study of methane point sources of the waste sector. We detected significant point source emissions at a majority (52%) of these sites, many with emissions persisting over multiple revisits (weeks to years). We compared these against independent contemporaneous in situ airborne observations at 15 landfills and established good agreement. Our findings indicate a need for long-term, synoptic-scale monitoring of landfill emissions in the context of climate change mitigation policy.

Climate Change Mitigation in Agriculture beyond 2030: Options for Carbon Pricing and Carbon Border Adjustment Mechanisms

SummaryIn the EU's climate policy, agriculture is covered as an Effort‐Sharing (ESR) sector, i.e. a sector beyond the Emission Trading System and LULUCF. Despite ambitious climate targets for the ESR sectors and an emerging focus on the need for agriculture to make a substantial contribution to climate change mitigation, agriculture has contributed much less to achieving climate targets than other ESR sectors in most EU Member States. A more radical mitigation instrument is required since the potential to increase climate efficiency in EU agriculture is limited. Carbon pricing is considered an effective instrument and is widely adopted in other sectors worldwide. Options on how to reduce related carbon leakage are discussed. Our recommendations for efficient climate change mitigation policy in agriculture are threefold. First, the agricultural sector needs more precise guidance and clear climate targets. Second, although preventing all conflicts between climate change mitigation actions and other policy goals is impossible and inefficient, a policy could minimise adverse effects. Third, since agricultural GHG emissions can only be minimised and compensated by negative emissions in other sectors, well‐defined intersectoral coordination is required.

Determinants and their spatial heterogeneity of carbon emissions in resource-based cities, China

Global climate change associated with increased carbon emissions has become a global concern. Resource-based cities, by estimations, have emerged as major contributors to carbon emissions, accounting for approximately one-third of the national total. This underscores their pivotal role in the pursuit of carbon neutrality goals. Despite this, resource-based cities have long been neglected in current climate change mitigation policy discussions. Accordingly, using exploratory spatial data analysis and Geographical Weighted Regression method, this study investigates the determinants of carbon emissions and their spatial pattern in 113 resource-based cities in China. It can be concluded that: (1) The proportion of carbon emissions from resource-based cities in the national total has shown a marginal increase between 2003 and 2017, and the emissions from these cities have not yet reached their peak. (2) A relatively stable spatial pattern of “northeast high, southwest low” characterizes carbon emissions in resource-based cities, displaying significant spatial autocorrelation. (3) Population size, economic development level, carbon abatement technology, and the proportion of resource-based industries all contribute to the increase in carbon emissions in these cities, with carbon abatement technology playing a predominant role. (4) There is a spatial variation in the strength of the effects of the various influences.

The Role of Renewable Energies for Sustainable Energy Governance and Environmental Policies for the Mitigation of Climate Change in Nigeria

In response to the escalating global challenges posed by climate change, this research investigates the role of renewable energies in shaping sustainable energy governance and environmental policies for climate change mitigation in Nigeria. The study underscores the pivotal relationship between renewable energies and governance structures, emphasizing the need for innovative policy approaches. In Nigeria, a country grappling with a surge in energy demand, particularly in densely populated urban areas, this research delves into the current state of renewable energy adoption, technological aspects, and the policy and regulatory frameworks governing its integration. The study scrutinizes the technological aspects of solar, wind, hydropower, and biomass energy in Nigeria, exploring advancements in solar photovoltaic, hydropower, bioenergy, and geothermal technologies. Additionally, it dissects the nation's policy landscape, assessing key initiatives such as the National Energy Policy, the National Policy and Guidelines on Renewable Electricity, and Feed-in Tariffs. Furthermore, the research examines the alignment of environmental policies with renewable energy goals, highlighting the importance of targets, incentives, and regulatory frameworks. It also scrutinizes incentives for sustainable practices in Nigeria, including investment tax credits, the Renewable Energy Development Fund, and concessional import duty rates for renewable equipment. The study assesses the impact of renewable energy initiatives in Nigeria, gauging investment trends, ongoing projects, and the effectiveness of policy frameworks. It also delves into the economic, social, and environmental co-benefits of renewable energy projects, emphasizing their role in job creation, investment attraction, and reduction in energy costs. Finally, the research evaluates the effectiveness of renewable energy initiatives in reducing the nation's carbon footprint and fostering environmental sustainability. It highlights progress in achieving climate change mitigation goals through increased renewable energy capacity, policy frameworks, and off-grid electrification initiatives.

How Does VR Affect Emotional Appeal and Persuasiveness of Gain Versus Loss-Framed Messages?

Can virtual reality (VR) lead to more desirable persuasion effects than videos in communicating the science of contentious issues like climate change? And, will these effects differ between messages that offer hope versus fear? We addressed these questions with a 2 (Modality: Desktop VR vs. Unidirectional video) × 2 (framing: Gain vs. Loss) between-subjects experiment ( N = 130), and found that VR triggered more fearful responses, which in turn led to more persuasive outcomes. It also increased individuals’ attitudes toward climate change mitigation policy when the experience was loss-framed, but backfired when the experience was gain-framed. Theoretical and practical implications are discussed.

Is carbon footprint reduction always preferred over offsetting? An analysis of tourists' preferences in the Mallorca region

This research is devoted to the analysis of tourists’ preferences for climate change (CC) mitigation policies in the Mallorca region. The stated choice experiment, used for evaluation, was designed combining a set of alternatives, characterised by carbon footprint reduction and offset policies, taking into account the existence of environmental direct benefits, but also indirect benefits that improve tourist experience or co-benefits derived from the location of policy projects. Economic welfare in form of willingness to pay (WTP) was estimated, and the alternatives were compared using compensating variation values. The study's findings validate the prevailing preference for carbon reduction policies over offsetting measures, except when the first don't have co-benefits and the latter are implemented locally. In the latter case, there is no significant difference in WTP between reducing the carbon footprint and locally offsetting it. Results not only contributes to the ongoing economic debate surrounding CC mitigation policies but also provides key information for designing mitigation schemes in diffuse emission sectors such as tourism.

Using climate financing wisely to address multiple crises

A convergence of several risk drivers creates the compound crises we see across the globe today. At the same time, the global humanitarian community and national institutions in affected countries are increasingly resource constrained. In this context, existing financing mechanisms should be evaluated for their potential to create synergies between social protection, peace, and inclusion objectives on the one hand and climate resilience outcomes on the other. The existing international architecture of climate change mitigation and adaptation policy and financing holds, in principle, the potential to address not only its main purpose of climate action, but also to contribute to development outcomes and address multiple risk drivers. Examples of this exist, but for these mutual benefits to emerge, and for climate finance to contribute more significantly to crises prevention, the agendas must become more aligned. Aligning several factors may enable coherence: i) Timeframes, from short-term response to multi-year programming; ii) Planning and targeting, moving towards conflict-sensitive area-based approaches and universal access to services; iii) Institutional arrangements and partnerships, coordinated national planning and jointly implemented local action.

Economic Policies for Climate Change Mitigation in the United States

Economic Policies for Climate Change Mitigation in the United States

THE FAIRNESS CONTROVERSY OVER CBAM AND ITS POLICY IMPLICATIONS

The idea of a carbon border adjustment mechanism (CBAM) has aroused fervent discussion recently. It is proposed as an effective tool to address the competitiveness loss and carbon leakage induced by unilateral carbon policies. Yet on the brink of this policy being rolled out, its ethical justification seems insufficiently clarified. CBAM implementation would provoke a huge fairness controversy. This paper illustrates the main ethical challenges impeding CBAM’s fairness perception. Two stand out in particular: The first is the lack of a global consensus on appropriate climate equity principles. This means that there is no basis for determining the fairness of CBAM’s burden shifting impact. The second is that CBAM is likely to undermine the procedural justice of the current quantity-oriented responsibility distribution regime under the Paris Agreement. We conclude that CBAM is not well-suited for solving the free-rider problem of the current climate change mitigation policies and emphasize that incentivizing innovation is key for an ambitious mitigation strategy.

The distributive politics of the green transition: a conjoint experiment on EU climate change mitigation policy

ABSTRACT In the fight against climate change, the European Union has developed a new growth strategy to transform Europe into the first climate-neutral continent by 2050. To support EU member states in their transition towards greener economies, climate change mitigation policies are being implemented at the EU-level. However, such policies can be designed in different ways, and gaining citizens’ support is crucial for the political feasibility of the European green transition. Drawing on data from an original conjoint experiment conducted in Germany (N = 5,796), this article investigates how policy design shapes public support for EU climate change mitigation. To this end, the study theoretically and empirically distinguishes four policy dimensions that address the distributive politics of the European green transition: sectoral scope, social spending, financing structure and cross-country distribution. The results confirm that all four policy dimensions significantly impact public support. Specifically, the study reveals that support is greatest for EU policy packages that target financial support at the renewable energy sector, include social investment policies, are financed by increasing taxes on the rich, and distribute resources across EU member states based on population size. Furthermore, citizens’ sensitivity to the policy design varies slightly by income position, left-right ideology and climate attitudes.

Interplay of Climate Change and Air Pollution- Projection of the under-5 mortality attributable to ambient particulate matter (PM2.5) in South Asia

Ambient fine particulate matter (PM2.5) pollution is a leading health risk factor for children under- 5 years, especially in developing countries. South Asia is a PM2.5 hotspot, where climate change, a potential factor affecting PM2.5 pollution, adds a major challenge. However, limited evidence is available on under-5 mortality attributable to PM2.5 under different climate change scenarios. This study aimed to project under-5 mortality attributable to long-term exposure to ambient PM2.5 under seven air pollution and climate change mitigation scenarios in South Asia. We used a concentration-risk function obtained from a previous review to project under-5 mortality attributable to ambient PM2.5. With a theoretical minimum risk exposure level of 2.4 μg/m3, this risk function was linked to gridded annual PM2.5 concentrations from atmospheric modeling to project under-5 mortality from 2010 to 2049 under different climate change mitigation scenarios. The scenarios were developed from the Aim/Endues global model based on end-of-pipe (removing the emission of air pollutants at the source, EoP) and 2 °C target measures. Our results showed that, in 2010–2014, about 306.8 thousand under-5 deaths attributable to PM2.5 occurred in South Asia under the Reference (business as usual) scenario. The number of deaths was projected to increase in 2045–2049 by 36.6% under the same scenario and 7.7% under the scenario where EoP measures would be partially implemented by developing countries (EoPmid), and was projected to decrease under other scenarios, with the most significant decrease (81.2%) under the scenario where EoP measures would be fully enhanced by all countries along with the measures to achieve 2 °C target (EoPmaxCCSBLD) across South Asia. Country-specific projections of under-5 mortality varied by country. The current emission control strategy would not be sufficient to reduce the number of deaths in South Asia. Robust climate change mitigation and air pollution control policy implementation is required.

Spatiotemporal patterns and drivers of the urban air pollution island effect for 2273 cities in China

Air pollution levels tend to be higher in urban areas than in surrounding rural areas, and this air pollution has a negative effect on human health. However, the spatiotemporal patterns of urban–rural air pollution differences and the determinants of these differences remain unclear. Here, we calculate the Urban Air Pollution Island (UAPI) intensity for PM2.5 and PM10 on a monthly, seasonal, and annual scale for 2273 cities in China from 2000 to 2020. Subsequently, we analyze the influence of urban characteristics using a combined approach of a two-way fixed effects model and a spatial Durbin model. Results show a strong downward trend in the UAPI intensity since 2013, with reductions ranging from 42 % to 61 % until 2020, for both pollutants and in summer as well as winter. Consistently, the proportion of the cities experiencing the UAPI phenomenon decreased from 94.5 % to 77.3 % for both PM2.5 and PM10. We find a significant influence of urban morphology on UAPI. Specifically, urban sprawl, polycentric development, and an increase in urban green spaces are associated with a reduction in UAPI, while dense urban areas intensify it. Our study also reveals a robust inverted U-shaped relationship between stages of economic development and UAPI. Moreover, economic development and air pollution itself show spillover effects that oppose their direct impacts. These results suggest that urban and regional planning and more ambitious climate change mitigation policies could be more effective strategies for mitigating air pollution in cities than end-of-pipe control.

Political trust and climate policy choice: evidence from a conjoint experiment

Abstract Why do citizens support or reject climate change mitigation policies? This is not an easy choice: citizens need to support the government in making these decisions, accept potentially radical behavior change, and have altruism across borders and for future generations. A substantial literature argues that political trust facilitates citizen support for these complex policy decisions by mitigating the cost and uncertainty that policies impose on individuals and buttressing support for government intervention. We test whether this is the case with a pre-registered conjoint experiment fielded in Germany in which we vary fundamental aspects of policy design that are related to the cost, uncertainty, and implementation of climate change policies. Contrary to strong theoretical expectations and previous work, we find no difference between those with low and high trust on their support for different policy attributes, assuaging the concern that low and declining trust inhibits climate policymaking.

The Impact of South Africa’s Carbon Tax Policy on Carbon Leakages on its Top Five African Trading Partners

The carbon leakage phenomenon, whereby decreased carbon emissions in locations with strict constraints on carbon emissions may be offset to some extent by increased carbon emissions in locations with less strict constraints on emissions, has the potential to undermine efforts to mitigating carbon emissions. As such the objective of this study was to use a natural experiment model to estimate the extent of carbon leakage associated with South Africa’s Carbon Tax on the combined carbon emissions of its top five trading African partners (Mozambique, Namibia, Botswana, Nigeria and Eswatini). This was a highly essential study and arguably a first of its kind, to infer causal impact of the carbon tax on carbon leakages using a single group interrupted time-series analysis regression discontinuity design. Results from the study showed that in the long-run, the carbon tax has decreased carbon emission in South Africa by 4.42 percent while increasing carbon emissions in South Africa’s trading partners by 1.003 percent. This shows evidence of a carbon leakage because of the carbon tax, and it is recommended that policymakers should consider trade restrictions to prevent the import of carbon-intensive commodities or institute universal, instead of unilateral, climate change mitigation policies.

The Impact of Climate Forcing Biases and the Nitrogen Cycle on Land Carbon Balance Projections

AbstractEarth System Models (ESMs) project that the terrestrial carbon sink will continue to grow as atmospheric CO2 increases, but this projection is uncertain due to biases in the simulated climate and how ESMs represent ecosystem processes. In particular, the strength of the CO2‐fertilization effect, which is modulated by nutrient cycles, varies substantially across models. This study evaluates land carbon balance uncertainties for the Canadian Earth System Model (CanESM) by conducting simulations where the latest version of CanESM's land surface component is driven offline with raw and bias‐adjusted CanESM5 climate forcing data. To quantify the impact of nutrient limitation, we complete simulations where the nitrogen cycle is enabled or disabled. Results show that bias adjustment improves model performance across most ecosystem variables, primarily due to reduced biases in precipitation. Turning the nitrogen cycle on increases the global land carbon sink during the historical period (1995–2014) due to enhanced nitrogen deposition, placing it within the Global Carbon Budget uncertainty range. During the future period (2080–2099), the simulated land carbon sink increases in response to bias adjustment and decreases in response to the dynamic carbon‐nitrogen interaction, leading to a net decrease when both factors are acting together. The dominating impact of the nitrogen cycle demonstrates the importance of representing nutrient limitation in ESMs. Such efforts may produce more robust carbon balance projections in support of global climate change mitigation policies such as the 2015 Paris Agreement.