4 Mar (CLIM/GEOL) Jared Nirenberg, Cold Seas in a Warmer Past

Speaker: Dr. Jared Nirenberg, Syracuse University

Time: Wed, 4 Mar, 1:30-2:30 pm ET

Location: 131 Innovation Hall and via Zoom (see above)

Title: Earth’s coldest regions in a past warmer world: High-latitude climate evolution during the Miocene

Hosts: Po Ju Chen,  Linda Hinnov

Abstract: The Miocene Epoch (5 to 23 million years ago) was a recent geologic interval when atmospheric greenhouse gas concentrations were similar to end of century projections. In this seminar, I will present novel analyses of deep ocean sediment cores from high-latitude sites to constrain the degree of high-latitude ocean warming as well as the response of polar climate systems, such as ice sheet behavior and terrestrial hydrology, to temperature changes during the Miocene. My work uses molecular biomarkers for proxy reconstructions of ocean surface temperatures and terrestrial precipitation isotopes from sediments recovered from the polar Southern Ocean near East Antarctica as well as the subpolar North Pacific. I will also discuss ongoing work, in collaboration with scientists at GMU, constraining atmospheric dynamics surrounding dramatic Arctic amplification during the Miocene. Together, these studies of polar paleoclimate dynamics during past global warmth have implications for long-term future climate.

Bio: Jared Nirenberg is interested in the climate of Earth's polar regions in the geologic past, about 15 million years ago. To research this, he uses marine sediment cores to analyze biomarkers, which are molecules produced by ancient organisms preserved in these sediments. From these geochemical analyses, Jared is reconstructing polar temperatures in the past when Earth's climate was much warmer than today, as a potential analogue for a future warmer world.