This year marks the 250th anniversary of the birth of Alexander von Humboldt (1769-1859), the intrepid explorer of the Andes and other regions in the world, and the most famous scientist of his time. Alexander von Humboldt is perhaps best known for his radical new vision of nature as a complex and interconnected global force, thereby becoming the founder of the field of biogeography and laying the ground for modern Earth-System Science approaches. It seems fitting to pay tribute to Alexander von Humboldt’s legacy by reviewing the state of the art in studies of the coupled lithosphere – atmosphere – hydrosphere – biosphere system with a focus on the Andean mountain belt. The Andes have become one of the main natural laboratories in the world to explore these questions and many recent studies have addressed its tectonic and geodynamic evolution, but also the two-way couplings between surface uplift, climatic evolution and biodiversity in the Andes and its foreland. This Union Session will bring together world-leading specialists on these questions with the aim to shed light on both suspected and unexpected couplings in the system.

Over the whole Earth history, the climate has encountered tipping points, shifting from one regulated system to the other. This tilting motion affects both climate and the carbon cycle and has played a major role in the evolution of the Earth climate, at all timescales. Earth History has been ponctuated by large climate changes and carbon cycle reorganizations, from large climate variations occurring in deep times (snowball events, terrestrialisation, Mesozoic and early Cenozoic warm episodes, quaternary glacial cycles…) to past and on-going abrupt events. Many potential triggers of those climate and carbon cycle shifts have been proposed and tested through modeling studies, and against field data, such as those directly or indirectly linked with tectonics (plate motion, orogenesis, opening/closing of seaways, weathering…) and orbital forcing. Given that the Earth climate is currently experiencing an unprecedented transition under anthropogenic pressure, understanding the mechanisms behind the scene is crucial.

Our aim is to point out the most recent results concerning how a complex system as the climate of the Earth has undergone many tipping points and what is the specificity of the future climate changes. Therefore, within this session, we would like to encourage talks discussing advances in our record and modeling of the forces triggering and amplifying the changes of Earth climate and carbon cycle across spatial and temporal scales.

In today’s changing world we need to tap the potential of every talented mind to develop solutions for a sustainable future. The existence of under-representation of different groups (cultural, national and gender) remains a reality across the fields of science, technology, engineering, and mathematics (STEM fields) around the world, including the geosciences. This Union Symposium will focus on remaining obstacles that contribute to these imbalances, with the goal of identifying best practices and innovative ideas to overcome obstacles.

EGU is welcoming six high-level speakers from the funding agencies and research centres on both sides of the Atlantic related to geosciences to present efforts and discuss initiatives to tackle both implicit and explicit biases. Speakers are:

Jill Karsten, AGU Diversity and Inclusion Task Force (confirmed)
Erika Marín-Spiotta, University of Wisconsin - Madison (confirmed)
Daniel Conley, Lund University (confirmed)
Giulio di Toro, University of Padua (confirmed)
Liviu Matenco, Utrecht University (confirmed)
Barbara Romanowicz, European Research Council (confirmed)

Atmospheric composition matters to climate, weather forecasting, human health, terrestrial and aquatic ecosystems, agricultural productivity, aeronautical operations, renewable energy production, and more. Hence research in atmospheric composition is becoming increasingly cross-cutting and linked to many disciplines including climate, biogeosciences, hydrology, natural hazards, computer and data sciences, socio-economic studies and many others. There is a growing need for atmospheric composition information and an improved understanding of the processes that drive changes in the composition and resulting impacts. While atmospheric composition research is advancing rapidly, there is a need to pay more attention to the translation of this research to support societal needs. Although translational research is a major focus of the health sciences and meteorology, it is in a relatively early stage in atmospheric composition. In this Union Symposium, we plan to highlight the need for, and to illustrate exciting advances in the translation of atmospheric composition research to support services. We will build upon work within the World Meteorological Organization and other communities related to the closer linkages of weather, atmospheric composition, and climate research and related services. We will also articulate the needs for advances in observing systems, models and a better understanding of fundamental processes. This session will also serve as a celebration of the 30 year anniversary of the WMO Global Atmosphere Watch programme and an opportunity for the broader community to envision partnerships needed to facilitate the effective translation of atmospheric composition research.