Foraminifera (see image) record the conditions of the water that they lived in when they were alive and building their shells (as known as tests). While at the University of Illinois Urbana-Champaign, I used forams deposited in a paleo-lagoon environment on Christmas Island to discover how hydroclimate shifted from 4500 – 1700 calendar years before present. I then used this data to extrapolate how the El Niño Southern Oscillation, the largest source of interannual climate variability on earth, behaved at this time.

Paleoclimate proxies give us access to climate data when we were not making observations and recordings of how the climate was shifting