Investigating connections between the geomagnetic field and climate change

Research indicates galactic cosmic rays (GCR) can contribute to the influence of clouds on Earth’s past climate (e.g. Carslaw et al., 2002). Water vapor coalescing around an aerosol initiates the formation of a cloud.  An increase in aerosols leads to a decrease in droplet size and an increase in cloud liquid water, which makes clouds brighter and blocks sunlight from reaching the earth’s surface, providing a cooling affect (Marsh and Svensmark, 2000). GCR’s provide ions for the production of aerosols, which influences the overall albedo of a cloud. In addition to being modulated by the solar magnetic field, GCRs are modulated by earth’s magnetic field, implicating that solar activity and earth’s magnetic field are correlated with changes in climate. The purpose of this research is to test whether changes in the geomagnetic field (e.g. paleointensity) affect variations in climate as observed through proxy measurements of d¹⁸O records.  Variations in the d¹⁸O from speleothem records at multiple latitudinal locations are used as signals of climate change through precipitation.  Paleointensity data compiled from multiple studies in the GEOMAGIA50 database (Korhonen et al., 2008) are used.  Paleointensity and d¹⁸O data are averaged over time using a running-window approach.  This research suggests that a correlation between variation in earth’s magnetic field and climate change exists and that studying the paleointensity of the geomagnetic field can help us better understand climate change in the past.