Marine EM & climate change

Earth's salty oceans are electrically conductive fluid passing through Earth's variable main magnetic field-- so they induce electric currents and magnetic fields of their own. Marine magnetic fields depend on the given ocean flow's transport and electrical conductivity (which in turn depends on temperature and salinity). Thus, monitoring marine magnetic fields can be a method for studying our oceans' changing transport, temperature, and salinity.

Below: figure from Schnepf 2017.