HIWAVES3 facilitates a dialogue between climate modelers, impact modelers and partners in different geographical regions with knowledge of local societal relevant meteorological events to construct stories of selected high-impact extreme events, simulated for present-day and future climate conditions. The story includes the origin of the extreme event from a meteorological perspective, its inter-regional linkages, its predictability, its societal impact and how climate change affects its magnitude and probability. Such stories, made available for schools, the general public and governments, are effective communication means, more so than bare numbers about the expected mean temperature increase, precipitation changes in percentages and such. Based on surveys, extreme summer events with large societal impacts, like droughts and floods, will be selected from the recent past for China, India and Europe. Similar events will be identified in large ensembles of global climate simulations. The size of the ensembles allows an analysis of the inter-regional linkages between the Arctic, the Midlatitudes and the Indian Monsoon region through large-scale Rossby waves and other meteorological factors leading to the extreme, like soil-moisture and sea-surface temperature conditions. In addition, a one in a thousand year event in China, India and Europe, although not witnessed in the recent past, will be analysed. The predictability of the event, weeks to months in advance will be assessed through additional simulations. Using empirical methods and process-based models, the impact on crop yields and economy will be estimated as well as the number of premature deaths. Using large ensembles under projected 2050 conditions the effect of climate change on these extremes and their impacts will be analysed. This research material is translated into powerful stories about concrete events that illustrate how climate affects man, man affects climate, how different geographical regions are connected and how extreme the weather might get. The meteorological data of these events will be made available for further impact studies.

Climate is currently changing mostly because of additional greenhouse gases, emitted through human activity, which are heating up the planet. Since future warming of climate is likely to cause damage to societies, governments are coordinating efforts to reduce greenhouse gas emissions to avoid these damaging consequences. However, despite the continuing rises in atmospheric greenhouse gas concentrations, the rate of warming of the Earth's surface has declined somewhat since the 1990s. While it is tempting to find a simple reason for this slowing (or "hiatus") in global surface warming, the climate system is extremely complex and there are many factors which can explain the lumps and bumps in the surface temperature record which also include increases (or "surges") in the rate of warming. The goal of our proposed programme of research is to understand much more fully how all the contributing factors can explain past hiatus and surge (H/S) events and this will ultimately help improve predictions of future climate change over the coming decades and far into the future. The potential causes of H/S events includes: natural (so-called unforced) climate variability, due to complex interplay between the atmosphere, oceans and land; natural climate change due to volcanic eruptions or changes in the brightness of the sun; changes in how heat is moved into the deep oceans due to natural variations or human-caused factors; changes in emissions of gases such as methane due to human activity; limitations in the distribution of temperature observations, such that the hiatus is partly an artefact of imperfect observations. Rather than one single cause it is likely that H/S events are caused by a combination of factors. This is why a large team with a broad range of expertise is required to evaluate the different processes together. Our project, Securing Multidisciplinary UndeRstanding and Prediction of Hiatus and Surge events (SMURPHS) has brought together a comprehensive community of researchers from 9 UK institutes supported by 5 project partners including the Met Office who are experts in the atmosphere, the oceans and the land surface. SMURPHS has 3 broad objectives, achieved through 6 research themes, which exploit theory, observations and detailed computer modelling. Objective 1 is to build a basic framework for interpreting H/S events in terms of energy moving between the atmosphere and ocean and to determine characteristics of and similarities between H/S events. Objective 2 is to understand mechanisms that could trigger H/S events and extend their length, considering both human and natural factors. Objective 3 is to assess whether H/S events can be predicted and what information is needed for near-term prediction of climate over coming decades which is important for how societies adapt to change. To meet these objectives scientists from a range of different disciplines will work on each of these possibilities and communicate their findings across the team. SMURPHS will produce a wide-ranging synthesis of its results. SMURPHS will have many beneficiaries. Beyond the global scientific community, improved understanding of H/S events is important at national and international levels for designing policies to control future greenhouse gas emissions and for effective adaptation to climate change. Intergovernmental Panel on Climate Change (IPCC) assessments have deeply influenced climate policy development at the international and national levels. Scientists involved in SMURPHS have contributed significantly to previous IPCC reports, and SMURPHS science and scientists would contribute significantly to future such assessments.

Biomass burning aerosol (BBA) exerts a considerable impact on regional radiation budgets as it significantly perturbs the surface fluxes and atmospheric heating rates and its cloud nucleating (CCN) properties perturb cloud microphysics and hence affect cloud radiative properties, precipitation and cloud lifetime. It is likely that such large influences on heating rates and CCN will affect regional weather predictions in addition to climatic changes. It is increasingly recognised that biomass burning affects the biosphere but the magnitude of the effects need to quantified. However, BBA is a complex and poorly understood aerosol species because of the mixing of the black carbon with organic and inorganic species. Furthermore, emission rates are poorly quantified and difficult to represent in models. It is now timely to address these challenges as both measurement methods and model capabilities have developed rapidly over the last few years and are now sufficiently advanced that the processes and properties of BBA can be sufficiently constrained by measurements; these can be used to challenge the new aerosol schemes used in numerical weather prediction (NWP) and climate models. Amazonia is one of the most important biomass burning regions in the world, being significantly impacted by intense biomass burning during the dry season leading to highly turbid conditions, and is therefore a key environment for quantifying these processes and determining the influence of these interactions on the weather and climate of the region. Though previous large scale studies of BBA over Amazonia and its radiative impacts have been performed, these are now over a decade old and considerable scientific progress can be made towards addressing all of the above questions given the rapid advance of models and measurements in recent years. We are therefore proposing a major consortium programme, SAMBBA, a consortium of 7 university partners and the UK Met Office, which will deliver a suite of ground, aircraft and satellite measurements of Amazonian BBA and use this data to 1) improve our knowledge of BB emissions; 2) challenge and improve the latest aerosol process models; 3) challenge and improve satellite retrievals; 4) test predictions of aerosol influences on regional climate and weather over Amazonia and the surrounding regions made using the next generation of climate and NWP models with extensive prognostic aerosol schemes; and 5) assess the impact of .biomass burning on the Amazonian biosphere. The main field experiment will take place during September 2012 and is based in Porto Velho, Brazil. At this time of year, widespread burning takes place across the region leading to highly turbid conditions. The UK large research aircraft (FAAM) will be used to sample aerosol chemical, physical and optical properties and gas phase precursor concentrations. Measurements of radiation will also be made using advanced radiometers on board the aircraft and satellite data will also be utilised. The influences of biomass burning aerosols are highly significant at local, weather, seasonal, and climate temporal scales necessitating the use of a hierarchy of models to establish and test key processes and quantify impacts. We will challenge models carrying detailed process descriptions of biomass burning aerosols with the new, comprehensive observations being made during SAMBBA to evaluate model performance and to improve parameterisations. Numerical Weather Prediction and Climate model simulations with a range of complexity and spatial resolution will be used to investigate the ways in which absorbing aerosol may influence dynamics and climate on regional and wider scales. At the heart of the approach is the use of a new range of models that can investigate such interactions using coupled descriptions of aerosols and clouds to fully investigate feedbacks at spatial scales that are sufficiently well resolved to assess such processes.

The goal of ACRoBEAR is to predict and understand health risks from wildfire air pollution and natural-focal disease at high latitudes, under rapid Arctic climate change, and resilience and adaptability of communities across the region to these risks. This will be achieved through integrating satellite and in-situ observations, modelling, health data and knowledge, and community knowledge and stakeholder dialogue.The Arctic has warmed rapidly over recent decades, at around twice the rate of global mean temperature increases, resulting in rapid changes to the high latitude Earth system. Changes in the high latitude terrestrial environment include observed increases in temperature extremes and precipitation patterns, which are leading to increasing trends in boreal wildfire and changes in the distribution of disease-carrying vectors, with evidence for emerging interactions between these changing risks. Recent years (including 2019) have seen unprecedented fire activity at Arctic latitudes, leading to unhealthy air quality in high latitude towns and cities. Vector-borne disease occurrence in these regions is also changing in response to rapid changes in temperature and moisture. Moreover, fire activity is intrinsically linked to changes in vector-borne disease risk through changing the habitat conditions for vectors and their hosts. Environmental, social, and governance factors specific to high latitudes hamper our current ability to understand community resilience and response to these changing risks. ACRoBEAR will tackle these urgent issues in the most rapidly warming region of the planet. To address these research challenges, ACRoBEAR brings together a diverse, international, interdisciplinary team of world-leading research groups and collaborators. The project will benefit from two-way dialogue with community groups and stakeholders throughout, across three key regions (Alaska, Eastern Siberia, Sweden). These groups will take an active part in co-design of specific research deliverables, and contribute local and indigenous knowledge to the development of new understanding within the project. ACRoBEAR aims to connect natural science with local community and stakeholder priorities, and to integrate natural science with local community knowledge and understanding. The ACRoBEAR team comprises world-leading experts in air pollution, climate science, natural-focal disease, social science and governance, landscape fire science, and health science, from across four European countries, Russia, and the United States. The unique interdisciplinary team will allow an end-to-end state-of-the art assessment of community resilience to changes in risk due to wildfire and natural-focal disease at high latitudes as a result of rapid Arctic warming. The planned workflow exploits cross-disciplinary collaboration and knowledge transfer to deliver integrated outcomes. ACRoBEAR will benefit a broad range of local and national-level stakeholders, including local communities, government, health and forestry agencies, and local and national policy makers. ACRoBEAR will deliver substantial impact on local communities, policy makers and health agencies in Arctic nations. Impact will result from providing new understanding to enable implementation of robust measures for mitigating harmful health impacts due to changes in high latitude wildfire and natural-focal disease and development of policy options to enable adaptation and increase resilience, tailored to regional communities and governance structures. The key legacy impact will be a series of web-based data tools and resources, carefully tailored to community and stakeholder needs via continual two-way dialogue throughout the project.

Meeting the Paris climate change commitments will be extraordinarily challenging, and even if they are met, may require extensive global deployment of greenhouse gas removal (GGR) technologies resulting in net negative emissions. If certain major emitters do not meet their Paris commitments and/or wider international cooperation is reduced then the trajectory needed to reduce emissions to Paris levels after a delay will be even more severe, potentially leading to the need for even greater reliance on such net negative emissions technologies. At present, the technical feasibility, economics, implementation mechanisms and wider social and environmental implications of GGR technologies remain relatively poorly understood. It is highly uncertain that GGR technologies can be implemented at the scales likely to be required to avoid dangerous climate change and without causing significant co-disbenefits or unintended consequences. Our GGR proposal presents a unique combination of a multi-scale assessment of the technical performance of GGR technologies with an analysis of their political economy and social license to operate, with a particular focus on how these elements vary around the world and how such considerations impact region-specific GGR technology portfolios. Currently, some portray GGR technologies as a panacea and virtually the only way of meeting aggressive climate targets - an essential backstop technology or a 'bridge' to a low-carbon future. One part of our project is to work with the models of the global economy (integrated assessment models) and better reflect these technologies within those models but also to use models at different scales (global, regional, national, laboratory scales) to understand the technologies better. We also seek to better understand how deployment of these technologies interact with the climate system and the carbon cycle and what the implications are for the timings of wide-scale rollout. By contrast, sceptics have expressed concerns over moral hazard, the idea that pursuing these options may divert public and political attention from options. Some critics have even invoked terms such 'unicorns', or 'magical thinking' to describe the view that many GGR technologies may be illusory. We will seek to understand these divergent framings and explicitly capture what could emerge as important social and political constraints on wide-scale deployment. As with nuclear power, will many environmentalists come to view GGR technologies as an unacceptable option? Understanding the potential scaling up of GGR technologies requires an understanding of social and political concerns as well as technical and resource constraints and incorporating them in engineering, economic and climate models. This aspect of our proposal necessarily brings together social science, engineering and environmental sciences. What is the biggest challenge to scaling up BECCS for example? Is it the creation of the sustainable biomass supply chain, the deployment of CO2 capture technology or the transport and storage infrastructure that is rate limiting? Or is it more likely the social acceptability of this technology? Further, we will provide insight into the value of international and inter-regional cooperation in coordinating GGR efforts. For e.g., would it make more sense for the UK to import biomass, convert it to electricity and sequester the CO2, or would it be preferable pay for this to happen elsewhere? Conversely, how might the UK benefit from utilising our relatively well characterised and extensive CO2 storage infrastructure in the North Sea to store CO2 on behalf of both the UK and others? More generally, we will explore how stakeholders in key regions view the suite of GGR technologies. Finally, we will quantify the option value of GGR - what is the value in early deployment of GGR technologies? How does it provide flexibility in meeting our near term carbon targets?