Program day 4

Convenors: Delphine Farmer - Colorado State University, USA; Alex Archibald - University of Cambridge, UK

Session description : Advances in understanding changes in the chemical composition of the atmosphere and interactions between changing composition and climate. This includes processes governing stratospheric ozone, atmospheric aerosols, and interactions with climate, but not air pollution.

Keynote speaker:

• "Imprints of climate variability and global change on tropospheric ozone trends", Arlene Fiore - Massachusetts Institute of Technology, USA - Remotely
• "The changing environmental impacts of fluorinated gases: Considering climate impacts and persistent product formation", Cora Young - York University, Canada
• "Climate driven interactions between the terrestrial biosphere and atmospheric composition", Catherine Scott - Leeds University, UK - Remotely
• "Key processes for bottom-up understanding of aerosol-cloud interactions and their implications of aerosol forcing: Highlights from the FORCeS project", Ilona Riipinen - Stockholm University, Sweden - Remotely

• "The importance of aerosol particles from Tropical latitudes in ice-cloud formation and climate", Louis Ladino - Universidad Nacional Autonoma de Mexico, Mexico

Convenors: Julie Arblaster - Monash University, Australia; Isla Simpson - UCAR, USA; Xiuqun Yang - Nanjing University, China

Session description: Contributions that assess climate and weather changes with an emphasis on understanding the underlying climate physics that generate such events. This covers changes in large scale atmospheric or oceanic circulation, as well as regional/local circulation changes such as storms and eddies.

• "Understanding changes in the North Atlantic Ocean circulation and the associated impacts on climate", Rong Zang - NOAA/GFDL, USA - Remotely
• "Atmospheric Circulation Adjustment Mediates Climate Changes between Tropics and Polar Region", Xichen Li - Institute of Atmospheric Physics, China
• "Global impact of recent Southern Ocean cooling", Sarah Kang - Ulsan National Institute of Science and Technology, Republic of Korea

Convenors: Adriaan Perrels - Finnish Meteorological Institute, Finland; Cocou Jaures Amegnaglo - University of Ghana, Ghana

Session description : Policy dialogue: common space for scientists and policy developers. Science diplomacy for climate action and sustainable development. Future climate scenarios and regional mitigation. Regional forcing, socio-economic drivers of regional climate change. Regional climate responses to mitigation actions (such as negative emissions, carbon dioxide removal (CDR), solar radiation modification (SRM) etc), including quantitative impact analyses. Regional climates and process responses under climate overshoot. Earth system response to strong mitigation with negative emissions. Climate services and systemic change. Informing science-based adaptation strategies.

Keynote speakers:

• "Assessing the ability to meet basic needs under mitigation pathways - considerations of fairness and climate justice in future climate scenarios", Keith Williges - University of Graz, Austria
• "Climate Scientists as climate negotiators for UNFCCC processes", Palmira Cuéllar - UnADM, Mexico

Convenors: Tufa Dinku - International Research Institute for Climate and Society (IRI), USA; Pablo Borges de Amorim - Gesellschaft für Internationale Zusammenarbeit (GIZ) , Brazil; Amanda Grossi - Columbia Climate School, USA

Session description : Understanding what constitutes good capacity development. Accommodating heterogenous development needs. Developing scientists’ capacity to understand decision context. Developing regionally appropriate good practices guidance. Institutional and individual capacity development. Developing regional research activities for experiential learning. Transdisciplinary collaboration.

Keynote speaker:

• "Institutional capacity building on spatial and temporal climate change analysis using CORDEX regional climate models over South Asia", Mandira Singh Shrestha - ICIMOD, Nepal
• "From Research to Practice: Integrating Climate Information into Agricultural Extension Systems in East, Southern, and West Africa", Amanda Grossi - Columbia University, USA

Convenors: Helene Seroussi - Dartmouth Engineering, USA; Timothy Naish - Victoria University of Wellington, New Zealand

Session description : Antarctic and Arctic regions
Advances in understanding and modelling atmosphere, ocean, cryosphere and terrestrial processes and interactions governing climate variability and change in polar regions. This includes sea-ice and permafrost.

Keynote speakers:

• "The polar tempest: remote sensing and modelling of how sea ice geometry drives polar air-sea interactions", Christopher Horvat - The University of Auckland, New Zealand - Remotely
• "Whither Antarctic Sea Ice?", James Renwick - Victoria University of Wellington, New Zealand - Remotely

Convenors: Eleanor Blyth - UK Centre for Ecology & Hydrology, UK; Anna Sörensson - Centro de Investigaciones del Mar y la Atmósfera (CIMA), Argentina; Aihui Wang - Institute of Atmospheric Physics (IAP), China

Session description : Processes involving land-air interactions, including the cycling of energy, water, carbon and momentum and boundary-layer dynamics and feedbacks. Four regional themes will be explored: (i) wet-tropical systems including rainfall-recycling and the impact of deforestation, (ii) processes that dominate semi-arid regions including small and large-scale atmospheric response to soil moisture dynamics, (iii) temperate systems including the important of agriculture and forestry on the physical climate system, and (iv) cold climate systems including the importance of snow cover. There will also be a focus on four emerging issues: (a) the role of vegetation and irrigation on monsoon systems, (b) key processes around wetlands, permafrost, peat soils and methane production, (c) understanding the response of ecosystems to slow changes in temperature, water and CO2 levels and (d) a focus on the impact of climate extremes and related phenomena such as fire on the atmosphere land interactions.

Keynote speakers:

• "Soil moisture persistence and its impact on multi-day storm predictability at the mesoscale – an illustration from the Sahel", Chris Taylor - UKCEH, UK
• "Strong soil moisture-atmosphere interactions on the Tibetan Plateau and its behind energy mechanism", Xianhong Meng - Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, China
• "Dry land surfaces and their effect on atmospheric circulation", Francina Dominguez - Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, USA - Remotely

Convenors: Masa Kageyama - Laboratoire des sciences du climat et l'environnement (IPSL-LSCE), France; Cristiano Chiessi - Universidade de Sao Paolo, Brazil; Kira Rehfeld - Tuebingen university, Germany

Session description : Advances in the evaluation of climate sensitivity, feedbacks and regional climate change based on paleoclimate data. Improving the understanding of climate variability and response to external forcing on different time scales using paleoclimate data. Using paleoclimate modeling and data to improve climate parametrizations.

Keynote speaker:

• "The spatiotemporal extent of the Green Sahara during the Last Glacial Period: Potential implications for early human populations", Yassine Ait Brahim - VI Polytechnic University, Morocco

Convenors: Daniela Jacob - Helmholtz-Zentrum Hereon, Germany; Asunción Lera St.Clair - Digital Assurance Research Center, Norway; Simon Marsland - CSIRO, Australia; Roché Mahon - Caribbean Regional Climate Center, Barbados; Mzime Murisa - START International, Zimbabwe

Session description: Growing climate impacts are leading to an ever-increasing demand for relevant climate knowledge and translation to inform decision and policy contexts. The climate knowledge user community has diverse needs across many different scales and cultures coupled with complexity of power relationships among societies, especially when comparing resource rich and poor nations. The science-policy interface requires transdisciplinary approaches to develop climate services through knowledge codesign, coproduction, and codelivery informing anticipatory adaptation to future challenges. We welcome perspectives on this rapidly developing and important area.

Keynote speakers:

• "Principles for co-producing climate services: practical insights from FRACTAL", Alice McClure - Climate System Analysis Group, University of Cape Town, South Africa
• "Transformation through transdisciplinarity", Heide Hackmann - University of Pretoria, South Africa
• "Co-production in Climate Services", Lucy Mtilatila - Malawi Government Information and Services, Malawi - Remotely

Convenors: Tannecia Stephenson - The University of the West Indies at Mona, Jamaica; Arona Diedhiou - Institut de Recherche pour le Développement (IRD), France; Mouhamadou Bamba Sylla - African Institute of Mathematical Sciences (AIMS), Rwanda

Session description : Assessment of climate change at regional level, including regional drivers and response. Focus on changes in dynamics, variability, predictability, and uncertainty. Studies with a focus on Africa are encouraged.

Keynote speaker:

• "Regional climate change assessments - where we are and future outlook", Erika Coppola - ICTP, Italy
• "A decade of CORDEX-Africa: Achievements, challenges and opportunities", Chris Lennard - University of Cape Town, South Africa
• "Global warming impacts on tropical cyclones: climate-scale statistics and event case studies", Chunyong Jung - Argonne National Laboratory, USA

Convenors: Douglas Maraun - University of Graz, Austria; Marjolijn Haasnoot - DELTARES, The Netherlands

Session description : Climate projections are uncertain because of unknown future forcings, model inadequacies and irreducible internal variability. This holds in particular for extreme events, tipping points and more generally low likelihood high impact events. Their occurrence may be plausible, we may even know that they are really possible, and we may have strong evidence that they become more likely with higher global warming. But these events are often not well captured by climate models and the associated uncertainties might be difficult to quantify. Despite uncertainty - or because of uncertainty – considering such events is relevant for adaptation decision making because of the high impacts and potentially transformative adaptation measures which take time to plan and implement. In this session, we aim to discuss uncertainties in climate projections, various approaches used to represent these uncertainties and the relevance and approaches to deal with them in adaptation decision making.

Keynote speakers:

• "Co-construction of knowledge for addressing climate change impacts and adaptation in Sénégal, West Africa", Amadou Thierno Gaye - Université Cheikh Anta Diop Dakar, Senegal
• "Projections or reality for decision makers: either/or, or both?", Judy Lawrence - Victoria University of Wellington, New Zealand - Remotely
• "Improving climate resilience of society using well-designed weather impact scenarios", Bart van den Hurk - DELTARES, The Netherlands