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Abstract

The geomagnetic field shields our habitat against solar wind and galactic cosmic rays. Since the magnetic shielding influences cosmic ray induced ionization of the atmosphere on centennial time-scales, it might have effects on cloud formation and consequently climate. In order to identify possible links between geomagnetic variations and climate change, which are controversially discussed, good global geomagnetic field reconstructions on multi-centennial to millennial time-scales are a prerequisite to interpret records of climate change. Scientists from GFZ together with collaborators from the US, Switzerland and Great Britain have worked on millennial scale magnetic field models for nearly 10 years. A first model spanning the past 10 kyrs, the Holocene, was published last year. The resolution and accuracy of the model is still limited due to data distribution and quality, but higher resolution models for the past 3 kyrs are feasible and have been published previously. These models provide continuous descriptions of dipole moment and tilt variations through the Holocene and of the global field intensity distribution, which all are relevant to estimate the magnetic shielding effect.