The late Miocene is an interesting historical period for paleoclimatologists since it underwent substantial climatic and ecological changes that helped shape our current climate. The world's surface waters have significantly cooled, according to tracers used to reconstruct past temperatures, but it is unclear how much of this cooling occurred in the tropics and how much of it was brought on by atmospheric Carbon Dioxide (CO2). We suggest a new reconstruction of sea surface temperatures from the Eastern equatorial Indian ocean (foraminifera) based on the temperature dependent ratio of magnesium to calcium discovered in fossil zooplankton shells.
