Satellite data and geomagnetic observatories give us a detailed picture of the modern geomagnetic field and the Sun–Earth system. To look further back, we can turn to geological archives, offshore cores, stratigraphic sequences, cosmogenic radionuclide records (e.g., ¹⁰Be), and geo/paleomagnetic reconstructions. Together, these records allow us to investigate how the Earth’s magnetic field, environmental conditions, and solar activity have changed over centuries, millennia, and longer geological timescales, and to explore the links between them. This long-term perspective is essential for understanding the modern Earth–Sun system, in which the geomagnetic field connects processes ranging from the Earth’s deep interior to the atmosphere and near-Earth space. It also often requires combining magnetic information with other proxies, models, and observations across different timescales. This combination can bring additional benefits, for example, helping to tackle the dating uncertainties that many paleo-sciences face.

This session welcomes studies linking geomagnetism, paleomagnetism, rock and environmental magnetism with solar variability (irradiance), cosmogenic radionuclides, paleoclimate proxies, space climate and other fields. We particularly encourage contributions that combine different geophysical and geological records, proxies, methods or timescales, including links with paleoclimate records, modelling, and modern ground-based and satellite observations. The session aims to bring these communities together and explore the links between geomagnetic, solar and Earth-system variability across different timescales.