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Opinion: The role of AerChemMIP in advancing climate and air quality research
Get PDFThe Aerosol Chemistry Model Intercomparison Project (AerChemMIP) was endorsed by the Coupled Model Intercomparison Project 6 (CMIP6) and was designed to quantify the climate and air quality impacts of aerosols and chemically reactive gases. AerChemMIP provided the first consistent calculation of effective radiative forcing (ERF) for a wide range of forcing agents, which was a vital contribution to the Sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change. It supported the quantification of composition–climate feedback parameters and the climate response to short-lived climate forcers (SLCFs), as well as enabled the future impacts of air pollution mitigation to be identified, and the study of interactions between climate and air quality in a transient simulations. Here we review AerChemMIP in detail and assess the project against its stated objectives, its contribution to the CMIP6 project, and the wider scientific efforts designed to understand the role of aerosols and chemistry in the Earth system. We assess the successes of the project and the remaining challenges and gaps. We conclude with some recommendations that we hope will provide input to planning for future MIPs in this area. In particular, we highlight the necessity of sufficient ensemble size for the attribution of regional climate responses and the need for coordination across projects to ensure key science questions are addressed. Summary data for CMIP6 and AerChemMIP models such as model components, model configurations, and emergent quantities are included
Decarbonising residential heating: local conditions and spatial spillovers driving heat pump uptake
Get PDFAir source heat pumps are the principal means of decarbonising residential heating. What drives local uptake of heat pumps? We present and examine a unique, highly disaggregated, spatial-temporal dataset for heat pump diffusion across Great Britain at the local authority level from 2010 to 2020. We find average total installed cost of 1075 pound/kW and a negative learning rate of -3.3 %, with most installations in owner-occupied houses. Using spatial econometric models, we investigate how local conditions drive heat pump installations. We find early adopting local areas tend to be rural, off the gas grid, with prior use of solid fuel or oil for heating, and participate in renewable and community energy projects. Early adopting areas benefit from a combination of more readily accessible properties, low-carbon energy skills, and local supply chains. We find robust evidence of spatial spillover effects that show early adopting areas serve as deployment test beds, indirectly stimulating deployment in contiguous areas. We reason that spatial spillovers are driven by installer availability and local supply chains materialised around installation activity. We estimate for every three heat pumps installed, one heat pump is subsequently installed in a neighbouring local authority with less advantageous conditions. This implies an important policy trade-off for low-carbon heat between maximising effectiveness (incentivise early adopters) and widening equality of access (support later adopters). Concerted policy action to tackle fragmented supply chains and skills shortages which inflate installation costs of heat pumps relative to gas boilers is also urgently needed
Temporal complexity of terrestrial ecosystem functioning and its drivers
Get PDFThe development of non-linear dynamics theory showed that simple processes can lead to high complexity in the functioning of nature, with ecological studies showing that non-linear dynamics are common across populations of different taxa. However, whether the energy and matter fluxes of entire ecosystems follow non-linear dynamics, and how complex these dynamics are, is still unknown. We investigate the drivers of- and trends in the temporal complexity of ecosystem functioning by calculating the correlation dimension of gross primary production (GPP), ecosystem respiration, and net ecosystem production. We use long-term, eddy-covariance C fluxes from 57 terrestrial ecosystems, including boreal, temperate, and Mediterranean biomes. Generally, ecosystems located under more temporally complex weather also show more complex C fluxes. Causal analyses indicate that larger C fluxes generally cause higher temporal complexity, and larger and temporally complex C fluxes reduce interannual variability, suggesting higher resistance to perturbations. We report a positive trend in GPP complexity over time, which correlates with increasing GPP. This result may indicate that ecosystems are increasingly responsive to endogenous or exogenous stimuli, but the biology underlying these trends is not yet understood. We show that the short-term temporal complexity of ecosystem functioning can elucidate ecosystem properties otherwise missed by longer timescales
Global challenges and the EU’s shifting agri-trade goalposts
Get PDFOver the past quarter of a century, the European Union has transformed itself from a defensive agricultural trade player into the world’s largest agri-food exporter and importer, driven by successive Common Agricultural Policy (CAP) reforms and market-oriented adjustments. This paper traces the evolution of EU agri-trade, highlighting the role of decoupled payments, structural competitiveness, and diversification of trade flows. It assesses the EU’s resilience to recent crises – from COVID-19 to energy shocks and the Ukraine war – while examining growing tensions between trade liberalisation, environmental standards, and geopolitical fragmentation. The analysis stresses the mounting challenges in reconciling climate goals with food security concerns and warns against regressive policy trends that ignore past reform achievements. Ultimately, the paper argues for maintaining evidence-based, market-oriented strategies to preserve the EU’s global leadership in sustainable agri-trade amid rising demands for food sovereignty and strategic autonomy
Out of the black into the green? Modeling the pathways for regional coal transitions
Get PDFCoal is a major contributor to anthropogenic carbon emissions and climate change. Coal mining and combustion are also a leading cause of premature mortality due to local air pollution. On the other hand, coal is central to many regional economies that rely on its mining, power generation, industrial use and exports. With changing climate and rising pollution levels associated with coal, the urgency for coal phase-out has become more prominent in recent years. This has put pressure on coal-dependent regional economies to implement energy transitions in a time bound manner. This paper studies optimal pathways for a coal phase-out within a small, open, regional economy consisting of a coal extraction sector, an energy sector composed of both coal-based and renewable power generation and a final consumption sector that relies on coal and electricity. Taking the perspective of a social planner who maximizes regional welfare and employing optimal control theory, we study the conditions under which coal extraction and fossil power generation are phased out, depending on preferences, cost and price structures. We also provide a systematic analysis of the dynamic processes associated with the transition out of coal of (formerly) coal-based regional economies, including the scope for multiple equilibria that may reflect stalling transitions. Our results will be relevant for regional governments in undertaking a transition away from coal in way that safeguards regional welfare and at the same time contributes to the global climate goals
Global warming amplifies wildfire health burden and reshapes inequality
No full textGlobal warming intensifies wildfires and exacerbates greenhouse gas and pollutant emissions1. However, global projections remain incomplete, hindering effective policy interventions amid uncertain warming futures2. Here, we developed an interpretable machine learning framework to project global burned areas and wildfire emissions. This framework accounts for the impacts of future climate change on fire activity and quantifies associated premature deaths and radiative forcing from fire-induced particulate matter (PM2.5). Here we show that from 2010–2014 to 2095–2099, fire carbon emissions are projected to increase by 23% under the Shared Socioeconomic Pathway (SSP) 2-4.5. Increased fire-related aerosols reduce the 0.06 W m⁻² cooling effect north of 60°N. Projections show a surge in premature deaths from wildfire smoke, reaching 1.40 (95% Confidence Interval: 0.66–2.25) million annually during 2095–2099, roughly 6 times higher than current levels. Africa is projected to experience the greatest rise in fire-related deaths (11-fold), driven by emission changes and an aging population. Europe and the U.S. would experience a 1–2-fold increase under SSP2-4.5, linked to rising fire occurrences in the mid-latitude Northern Hemisphere. Overall, the health burden would become more evenly distributed across nations of differing development levels than present patterns, underscoring the need for coordinated efforts
Sustainable Management of Banked Fluorocarbons as a Cost-Effective Climate Action
No full textFluorocarbon banks present a substantial yet largely untapped opportunity for climate change mitigation within current regulatory frameworks. This potential can be effectively addressed through fluorocarbon lifecycle management (FLM), a strategy grounded in circular economy principles. This study quantifies the mitigation potential of FLM in China from 2025 to 2060, employing a tailored emission modeling framework and country-specific cost analysis. If unmitigated, these banked fluorocarbons could add 0.014 °C to global warming by midcentury. FLM, however, could prevent up to 8.0 Gt CO2-eq of cumulative emissions by 2060, with 93.2% attainable at costs below 10 USD/t CO2-eq─an additional mitigation exceeding 50% of the 13 Gt CO2-eq reductions pledged under the Kigali Amendment in China. Meanwhile, reclamation efforts could redirect up to 4108 kt of fluorocarbons for reuse or repurposing, conserving resources otherwise needed for virgin production. Our findings underscore FLM as a cost-effective approach to bridging the emission gap while advancing global sustainability
Land remains a blind spot in tracking progress under the Paris Agreement due to lack of data comparability
Get PDFLand carbon fluxes are key to the Paris Agreement. However, data comparability issues persist between countries’ land greenhouse gas inventories and mitigation targets, and what land models (bookkeeping and integrated assessments) provide as Paris-aligned benchmarks for land. As a result, the Global Stocktake, aiming to track collective mitigation progress, did not explicitly consider country targets for land. This blind spot leaves countries uninformed of the 2030 gap between their ambitions for mitigation on land and models’ benchmarks. Here we track the contribution and evolution of land-related targets under countries’ 2020 Nationally Determined Contributions, splitting land pledges between reduced emissions and additional sinks. Land retains a quarter of the global mitigation pledges in 2030, mostly relying on external support (−1.5ǂ1.1 GtCO 2 e/yr), of which −0.55 GtCO 2 e/yr are additional sinks. It is crucial that future Global Stocktakes include appropriate comparisons between modelled and country-provided land use net emissions. We here offer some concrete suggestions
Future river exports of nutrients, plastics and chemicals worldwide under climate-driven hydrological changes
Get PDFFuture climate-driven hydrological changes may strongly affect river exports of multiple pollutants to coastal waters. In large-scale water quality models the effects are, however, associated with uncertainties that may differ in space and time but are hardly studied worldwide and for multiple pollutants simultaneously. Moreover, explicit ways to assess climate-driven uncertainties in large-scale multi-pollutant assessments are currently limited. Here, we aim to build trust in future river exports of nutrients (i.e. nitrogen and phosphorus), plastics (i.e. micro and macroplastics), and chemicals (i.e. diclofenac and triclosan) under climate-driven hydrological changes on the sub-basin scale worldwide. We used a soft-coupled global hydrological (VIC) and water quality (MARINA-Multi) model system, driven by five Global Climate Models (GCMs), to quantify river exports of selected pollutants to seas for 2010 and 2050 under an economy-driven and high global warming scenario. Subsequently, we developed and applied a new approach to build trust in projected future trends in coastal water pollution for the selected pollutants. Results reveal that in arid regions, such as the Middle East, East Asia, and Northern Africa, climate-driven uncertainties play a key role in future river exports of pollutants. For African sub-basins, high increases in river exports of pollutants are projected by 2050 under climate-driven hydrological uncertainty. Nevertheless, over 80% of the global sub-basin areas agree on the direction of change in future river exports of individual pollutants for at least three GCMs. Multi-pollutant agreements differ among seas: 53% of the area agrees on increasing river exports of six pollutants into the Indian Ocean by 2050, whereas 17% agrees on decreasing trends for the Mediterranean Sea. Our study indicated that even under climate-driven hydrological uncertainties, large-scale water quality models remain useful tools for future water quality assessments. Yet, awareness and transparency of modelling uncertainties are essential when utilising model outputs for well-informed actions
The growing gap in cognitive skills within and between countries
Get PDFIn this contribution two recent studies on the inequality of trends in cognitive skills are discussed. One uses longitudinal data on tested adult literacy and numeracy in Germany and finds that for the more educated and those in intellectually demanding jobs, skills continue to improve up to higher working ages, while for those with low starting levels and blue-collar jobs, skills start to decline already in the thirties. Another study estimates global level trends in skills in literacy adjusted mean years of schooling and finds a growing gap in skills between countries, despite some convergence in formal educational attainment levels. This article discusses selected possible consequences of this growing inequality in skills within and between countries, and outlines a further research agenda