WCRP invites you to discuss progress and new challenges in understanding climate variability and change, as part of a coupled physical, biogeochemical, and socio-economic system. We will discuss ways in which we envision improving our understanding of the drivers and interactions that lead to global and regional changes in climate dynamics, in particular oceanic and atmospheric circulations. The profound nonlinearities of these systems continue to present critical emerging questions at a range of scales from local and regional weather to global modes of climate variability.

The mechanisms responsible for radiative, hydrologic, cryospheric and biogeochemical changes determine our ability to quantify the reservoirs and flows of energy, water, carbon, and other climate-relevant compounds. We will discuss how to advance this quantification, within and between the sub-systems of the climate system, as an important check on our evolving understanding of fundamental processes.

WCRP invites you to discuss the latest progress and new challenges in prediction capabilities and research-operation linkages with a specific focus on extremes within a changing climate. Climate variability will continue to challenge our resilience and preparedness to high impact weather and climate extremes in the near term, and accurate climate prediction offers significant opportunities to manage these risks.

In this Town Hall we will discuss the requirements for accurate climate prediction, including the ability to quantify uncertainties, limits of predictability, capacities of operational prediction systems and needed advances in the foundational mathematics of climate predictability. We will discuss the processes responsible for the existence of regional climate hotspots, as well as the potential for crossing thresholds and anticipating events not yet on record. The ways in which the non-stationarity of the Earth system interacts with “fast” (such as hurricanes) and “slow” (such as droughts) extremes will also be explored.

WCRP invites you to discuss the latest progress and new challenges in simulation capabilities in order to assess the response of the climate system to natural and anthropogenic forcings, feedback mechanisms and emergent constraints across Earth System component on multidecadal time scales.

In this Town Hall we will discuss the requirements of future climate projections, including the limits of prediction and associated uncertainties. We will discuss non-linear processes and internal variability, and the system sensitivities to imposed forcing, such as fossil-fuel emissions, land use change, volcanic eruptions, and solar variability, which can inform climate change projections and scenarios. We will also discuss developing ideas on emergent constraints and how to reduce uncertainty in model projections and climate sensitivity. Particular questions arise in relation to how to make a detailed representation of complex interactions between aquifers, vegetation and soil carbon, or between permafrost, glaciers, and ice-sheets as well as human activities influencing the climate system. To advance support of climate services for adaptation, the use of dynamical and statistical downscaling tools to better represent regional and extreme phenomena will be explored.

WCRP invites you to review progress and discuss emerging challenges in climate-society interactions and in generating decision-relevant climate information and knowledge in support of policy and services. Climate information presents tremendous opportunities to collaborate with civil society, governments and private industry to safeguard lives and valued assets. Socio-economic processes have intrinsic roles in the Earth System, and human communities and institutions cannot be separated in any meaningful way from the physical, chemical and biological systems that support them. Fundamental aspects of emergent behaviors can be incorporated into a comprehensive understanding of the coupled Earth system. In this Town Hall we will discuss the technical capabilities that can allow socio-economic processes to be incorporated into integrated assessment models, which can in turn support broader climate scenario simulations.

Climate science is generating a wealth of data which requires distillation from multi records and model simulations into information and knowledge. The transfer of uncertainties along the generation process is very complex but a necessary condition to make informed decisions and manage risk. This Town Hall will discuss the innovative techniques, such as data mining and machine learning, that are required to sort through this vast amount of information, reconcile and explain various outcomes and extract useful knowledge. We will explore the pathways to obtaining actionable climate information, accurate scientific assessments and public communication strategies, all of which require collaborative efforts with multi-sectoral actors in all regions of the globe.