Air conditioning (AC) has emerged in the 1950s United States as an effective way to cope with heat stress. It has since then massively spread across North America, Japan and urban China, but very little in the developing world. Despite providing important benefits, it generates greenhouse gas emissions by using electricity and leaking hydrofluorocarbons (HFCs), thereby adding a dangerous positive feedback loop into the climate system. Moreover, it is suspected to have adverse effects on health (by decreasing physical activity) and diverting resources away from traditional heat-proof habitat. The global expansion of AC is expected to take a new, dramatic turn with the combination of global warming, income rise and urbanization. This confluence of factors is expected to be most critical in African countries, were AC ownership rates are currently below 1%. Despite the importance of the challenge, AC is virtually unstudied in African contexts. There is thus an urgent need to fill this gap and provide policy recommendations for sustainable cooling in Africa. The AFRICOOLING project is committed to seizing this timely research opportunity. To do so, it will take an integrated demand- supply-policy approach to cooling and explore blind spots in it in three inter-related work packages (WP). On the demand side, research into the adoption of cooling technologies has focused on temperature and income as the main determinants. A broader set of factors needs to be investigated, including health, behaviors, attitudes, new electricity pricing schemes, and, crucially, dynamic effects such as heat waves. To address this gap, WP1 will consist in conducting comprehensive household surveys (N=400 in each) in Mombasa and Mwingi in Kenya and Abidjan in Côte d'Ivoire. The same households will be surveyed every year so as to build a 4-year dataset fit for capturing a broad range of effects. The team will benefit from field support from the University of Nairobi, Institut Polytechnique Houphouët-Boigny (INP-HB) and Institut de Recherche pour le Développement (IRD). On the supply side, research has focused on long-term price and efficiency adjustments in AC retail in the United States. In an attempt to generate broader insights, the coordinator has started assembling a high-frequency database of cooling products in 13 African countries in June 2019. E-commerce data are collected for 13,000 cooling products (AC, fans, refrigerators) and a control group of other products (smartphone, rice, etc.) on a daily basis. In WP2, this work will be continued so as to provide 6 years of data by the end of the project. In addition, on-site visits will be conducted in Kenyan and Ivorian retail stores and at street corner merchants to complement the online data with offline ones. On the policy side, research has documented very few conventional policies such as energy efficiency labels for AC across Africa. Meanwhile, non-conventional policies such as import bans on second- hand appliances have been documented in Ghana. Yet more policies are supposed to be adopted under the international framework of the Kigali Amendment to the Montreal Protocol, imposing HFC phase-downs. In WP3, a more systematic analysis of African cooling policies will be conducted and complemented with interviews with stakeholders in the Kigali Amendment to identify the key factors of policy effectiveness at both the global and domestic levels. The results from the different WPs will be integrated into a final WP generating contrasted cooling pathways and making policy recommendations for promoting the more sustainable ones. The project will gather an interdisciplinary team of 11 highly qualified experts from the coordinator's close circle and beyond, and allow him to hire a PhD student and a three-year postdoc. Following the highest ethics standards, it will produce extensive, novel and highly valuable datasets that will be made broadly accessible.

The aim of the Theia/OZCAR Information System (IS) is to make all the continental surfaces in-situ data visible and easy to access and to facilitate their discovery on a single portal managed by the French data pole “Theia”. The project will start with the OZCAR (French network of Critical Zone observatories) Research Infrastructure (RI), before extending to data from other sources (research programs, non-labeled observatories). The IS is currently developed, based on data exchange standards (INSPIRE, OGC) and is committed to implementing the FAIR principles, especially to prepare the French community to integrate European RI such as eLTER-RI (European Long Term Ecological Research), recently accepted on the European roadmap and whose French mirror eLTER-France includes the OZCAR RI. The IS will also allow data DOI assignment with rich metadata. The OZCAR RI coordinates 21 labeled observatories which manage some sixty sites in France and abroad (North and West Africa, Asia, South America, Arctic) ranging from a few hectares to several hundred km². These observatories collect in situ long-term data from continental areas, some of which start as early as 1960. The initial practices and objectives of the observatories are different, which has led to the choice of different sampling protocols and measuring sensors. In the current census there are more than 300 variables measured by OZCAR observatories (including both physical variables and chemical species). In situ data are mainly point time series, but also gridded data, vector data, or 2D profiles. The complexity of Theia/OZCAR IS does not lie in the total amount of data stored (around 10 TB), but in the variety of data and metadata needed to contextualize them (variables, objects of interest, acquisition methods); and the heterogeneity of existing distributed information systems to describe and disseminate data from each observatory. To develop the Theia/OZCAR IS it was chosen, in agreement with the experience of the Earth System RI, to leave the data close to the producers, to ensure their quality. The observatories will continue to distribute their data in the IS they have developed, while a pivot model with rich metadata based on standards, has been defined to ensure the flow of information between the observatories and the Theia/OZCAR IS, which implements the FAIR principles. This iterative approach creates a network and allows to rely on the complementary skills of the observatories IT Teams in term of data management. A data portal prototype, focused on point time series, is available and a third of the observatories have already implemented information flows with the Theia/OZCAR IS. The FairTOIS project aims to consolidate and enrich the implementation work of the FAIR principles started two years ago on 3 aspects: (1) data discovery through standardized variable names and object of interest, as well as access to data; (2) development of data interoperability; and (3) dissemination of FAIR data principles in the Continental Surfaces community via the OZCAR RI. All of these developments will be carried out, as for current developments, in connection with the Earth System RI and data poles of other disciplines, to ensure the interoperability of systems and data. The work done will also allow the French community to be a source of proposals for the construction of the eLTER IS, having already a shared vision of the management of a much wider data panel than the one currently treated in eLTER.

CASPA (Climate-relevant Aerosol Sources and Processes in the Arctic) aims to gain new fundamental insights into processes governing the formation and distribution of anthropogenic aerosols originating from local, relative to remote, sources to reduce uncertainties in model predictions of aerosol impacts on Arctic climate. The focus is on winter and early spring when anthropogenic emissions contribute most to the widespread pollution Arctic Haze. Aerosols are important short-lived climate forcers in the Arctic, a region undergoing unprecedented changes, due to rapid warming. Improved understanding is crucial given potential risks from already significant and increasing local anthropogenic emissions. Modelling correctly the compositional mix and vertical distributions of Arctic aerosols in the lower atmosphere is important for quantification of direct and indirect radiative effects. Individual chemical and physical processes driving the formation and evolution of aerosols in the Arctic are not sufficiently constrained by the few available observations, especially in the wintertime when our knowledge is very poor. For instance, formation mechanisms of secondary aerosols, such as sulphate or organics, remain rather puzzling in cold, dark/dim wintertime Arctic conditions. The acute lack of relevant process-level data is partly responsible for very diverse and often poorly simulated Arctic aerosols. This hampers our ability to correctly assess impacts of local and remote anthropogenic emissions on Arctic aerosols and climate. CASPA addresses important knowledge gaps via 3 inter-related scientific objectives (work packages) to improve characterisation, understanding and model treatments of processes governing 1) sources and formation (oxidation) pathways for Arctic aerosols, 2) the role of Arctic boundary layer transport and mixing on the formation and vertical distributions of aerosols, leading to 3) improved simulation of local, relative to remote, anthropogenic sources on Arctic-wide aerosol distributions and their impacts on climate. A combination of collection of new data (precursor gases, oxidants, aerosols, dynamics) and chemical-aerosol-climate modelling will be used leading to improved Arctic aerosol and climate predictive capabilities. New data will be collected as part the first major, international Arctic field campaign examining wintertime aerosols (IGAC-Future Earth/IASC) PACES-ALPACA. We will deploy state of the art instrumentation in January-February 2022 in Alaska to characterise inorganic/organic aerosols, vertical layering and mixing of aerosols and precursors (ground-based, radar, in-situ profiles, masts) at sites influenced by local emissions and Arctic Haze. Filters will be collected for novel laboratory isotope analyses giving insights into aerosol formation rates. All these field data will be analysed, in combination with multi-scale modelling, in order to evaluate and improve process-level treatments in local, regional (Alaska) and Arctic wide (hemispheric) model simulations. The improved model will be used to quantify local, relative to remote, source contributions and their radiative effects. CASPA brings together 6 complementary French groups working on atmospheric chemistry, dynamics and geochemistry, working in close collaboration with international PACES teams. Science results will be communicated to the wider modelling community, stakeholders, including policy makers (Arctic Council, IPCC) and the public via outreach activities, also involving industry collaborators.

Over a large part of Antarctica, the surface mass balance (SMB) is controlled by a few extreme events, resulting in a high natural variability of this parameter. In particular, extreme moisture intrusions linked to Southern Ocean Atmospheric Rivers (ARs) have been recently demonstrated to be major sources of both snow accumulation, heating and surface melt. Despite their key role, there is a general omission of AR variability, and more broadly of extreme events, in studies of past and future Antarctic climate and SMB. ARCA will assess the impact of ARs on the surface mass balance of Antarctica and will explore to what extent past AR activity can be recorded in ice cores. To reach this goal, ARCA is organized in 4 working packages. 1) ARCA will use recent novel numerical methodologies for identifying ARs applied to global and regional circulation models (GCMs and RCMs respectively). New algorithms will be applied to historical, present and future climate simulations. 2) ARCA will provide new field measurements of water stable isotopes and chemistry composition of snow precipitation and air masses from Adelie and Wilkes Lands, and 3) apply a regional scale modeling of water stable isotopes to interpret the signal observed in the field. 4) ARCA will finally revisit data from existing ice cores (aerosol content, e.g. sea salt, insoluble particles, water isotopes). Following this methodology, ARCA proposes to: 1) understand how natural variability and external forcings control the AR activity. 2) quantify AR moisture and heat transport towards Antarctica and their impacts on the SMB of Antarctica. 3) describe AR impact on the isotopic and aerosol contents of air masses transported through East Antarctica, 4) analyze the processes (e.g., moisture origin, sublimation of hydrometeors) producing characteristic signals in air masses during ARs, 5) estimate the induced bias in ice core records in regards to past temperature reconstructions. 6) Evaluate (qualitatively) past AR variability and the resulting bias in current estimates of past millenium climate in Antarctica. The ARCA project will deliver products that describe AR climatology and variability (occurrence maps, statistics), their atmospheric moisture signature (time-series of isotopes and aerosol content), and their impacts on Antarctic climate and SMB (through maps of induced melting and accumulation). Results will be presented for the 20th and 21st centuries, aiming in particular at projecting observationally constrained impacts of ARs on the SMB. ARCA will define a multi proxy approach to define how past AR could be retrieved in ice cores and provide a metric using water isotopic composition in ice cores to qualitatively define periods of higher and lower AR activity over the past millennium. Finally, ARCA will define the regions of Adelie and Wilkes Lands where ice cores should be drilled to best capture the AR and their influence in past climate variability. The ARCA consortium presents recognized experts from the IGE, LSCE and LOCEAN in particular in atmospheric modeling with polar-Regional Circulation Models and General Circulation Models, AR detection and estimation surface mass balance for Antarctica. The project will also rely on the broad expertise of the group in the interpretation of water isotopes and aerosol contents in air samples and ice cores.

Shipping is an essential transport infrastructure, with 80% of our goods undergoing overseas transport. However shipping emissions have impacts on climate change and on air quality, through the emission of gaseous (SO2, NOx, CO2, VOCs…) and particulate (PM) pollutants, particularly important for highly populated coastal areas. Since the 90s, regulations for emissions started to evolve, leading to the current limitations of fuel sulphur content (0.5%) and the application of Tier I - III standards for emissions. It is however likely than further changes need to be implemented to move towards more sustainable practices, particularly in harbors. But it is currently highly challenging to estimate the impact of shipping emissions on urban air quality, due, amongst others, to the transient nature of shipping plumes, the differences between vessels and fuels used, and the lack of understanding of the chemical evolution of the pollutants, which currently hamper accurate modelling of current and future changes. The project SHIPAIR therefore proposes to tackle some of these challenges through an interdisciplinary approach, combining online (& off-line) measurements with real-time shipping data through the automatic identification system and novel modelling approaches. Two field campaigns will inform not only on the pollutants emitted, but also on their evolution during transport and on their oxidation potential (OP). The first measurement campaign is an intensive (3 weeks) field campaign in the harbor of Dunkirk. Measurements on two locations, one near-field and one close to the urban border, of a comprehensive suite of pollutants (gas and particulates, including on-line metal speciation) will allow a better estimate of their evolution, their influence on the OP and on urban AQ. Furthermore, the deployment of a photochemical flow reactor will allow to assess the secondary aerosol formation potential of the plumes. The second measurement campaign will take place during one year in an urban monitoring site in Marseille, focusing on the deconvolution of different source contributions, in particular to the OP. The deployment for the first time of a novel online instrument to measure OP with a 20-minute time resolution over a long time period (3-4 months), will produce a unique, high resolution data set. The data obtained through these campaigns will be analyzed using state-of-the-art positive matrix factorization (PMF) in order to disentangle different source contributions. For the local AQ networks (AASQA) involved in SHIPAIR, a major challenge in predicting AQ in port cities, is the unequal access and use of information. To counter this difficulty, the 3 AASQAs will work closely together to harmonize and standardize their modelling approach in close collaboration with the port authorities. The emission inventories used will be enlarged based on literature and ongoing projects. Another difficulty in modelling the AQ of urban center close to harbors, lays in the resolutions of the models and their limited representation of atmospheric processes, affecting notably the accuracy of prediction for ultra-fine particles and the chemical composition of PM. SHIPAIR proposes to develop a new dispersion modelling framework for ship plumes in urban areas, based on a “plume-in-grid” and a “street-in-grid” approach. Furthermore, the model will integrate the treatment for metallic compounds in the SSH-aerosol module, allowing to investigate the contribution of metals to the OP. This new modelling framework will be evaluated against the measurement dataset from the campaigns and the AASQAs. Finally, SHIPAIR will compare the impact of shipping emissions determined by the different methodologies (PMF and model with and without shipping emission) for different harbors (Dunkirk, Marseille and Le Havre). After validation first runs of scenarios for future trends will be implemented by each AASQA to evaluate the impact of local mitigation strategies.