One hundred and thirty thousand years ago, Earth entered a warming transition period, from an ice age to the beginning of the Eemian Interglacial Period. While Neanderthals were recolonizing northern Europe and Homo sapiens were exploring routes beyond the African continent, the planet was home to an impressive megafauna, including mammoths, mastodons, and saber-toothed tigers, during a period when global temperatures were higher than they are today and sea levels were several meters higher than they are now.
What was the climate like during that period in the South Pacific Ocean and in Chile? What processes allowed the planet to reach those temperatures? And, above all, what can that past teach us about the Earth’s future climate? These are some of the questions that Dr. Cyrus Karas, a researcher at Usach, seeks to answer through a Fondecyt Regular project that will study seafloor records off the coast of Chile and in the eastern equatorial Pacific.
The research will reconstruct the oceanic and atmospheric conditions of that era to understand how the oceans, ocean circulation, and both regional and global climates responded to a warming scenario similar to the one we are experiencing today.
“We are studying an important period in the past when the planet was even warmer than it is today. This serves as a window into the future, because if we find conditions similar to those we might experience in the coming decades, we can better understand how the climate system responded and what might happen,” says the researcher.
The research team is analyzing deep-sea sediment cores retrieved from the seafloor off the Chilean coast through to the eastern equatorial Pacific—a strategic route for studying Pacific ocean circulation.
“Chile is situated precisely at a junction where water masses from the polar and tropical regions of the Pacific converge. These water masses form in the Southern Ocean, where they absorb CO₂ from the atmosphere and then travel northward at depth, eventually resurfacing in the equatorial Pacific, where the ocean releases CO₂ back into the atmosphere. That is why it is so important to study this area during the warming leading up to the Eemian interglacial, because it allows us to better understand how the ocean transports carbon dioxide and how that may have influenced current climate change,” says Dr. Karas.
Using sediment cores, the team will analyze various geochemical and physical indicators to reconstruct variables such as ocean temperature, salinity, water mass circulation, and carbon dioxide concentration during this important climatic transition.
The results obtained will subsequently be compared and incorporated into climate models to reconstruct climate change during one of the warmest periods in Earth’s recent history and to assess the role the ocean played in this process.
The project is scheduled to run for four years and involves collaboration with leading international research centers, including the Alfred Wegener Institute for Polar and Marine Research (AWI) and the GEOMAR Helmholtz Center for Ocean Research Kiel, both in Germany. This network will complement the analyses conducted in Chile with specialized geochemical techniques for studying marine sediments, strengthening the team’s ability to reconstruct one of the warmest periods in Earth’s recent history and provide new evidence for understanding current climate change.
Spanning four years, the Fondecyt research project features strategic collaboration with world-class oceanographic institutions, including the Alfred Wegener Institute for Polar and Marine Research (AWI) and the GEOMAR Helmholtz Center for Ocean Research Kiel in Germany. This international network integrates advanced geochemical marine sediment analysis with local Chilean data, building a high-resolution benchmark of Earth's past warming to better inform modern climate change projections.
“Chile is an extraordinary natural laboratory for studying the ocean and climate. We have an extensive coastline and a privileged location for researching these processes, so I hope this project will help generate knowledge that allows us to better understand how the climate system works and make more informed decisions in the face of the changes to come,” concludes the USACH scholar.