James C. Zachos

The 2016 Milutin Milanković Medal is awarded to James C. Zachos for his groundbreaking contributions to documenting and understanding climate change throughout the Cenozoic.

From the early days of his career to the present, James Zachos has been at the scientific forefront of palaeoclimatology and palaeoceanography. His work deciphering climate archives from deep‐sea sediments completely reshaped our views of long‐term climate change as well as rapid climate transitions during the past 65 million years.

In his earlier years, Zachos contributed significantly to the understanding of biological and carbonate pumps in the ocean in the aftermath of the Cretaceous–Palaeogene boundary mass extinction event. His work on Antarctic glaciation across the Eocene–Oligocene transition, and its effect on climate and global carbon cycle resulted in landmark papers.

In the early 90’s, Zachos was amongst the first to see the opportunities presented by the importance of a rapid episode of climate and carbon cycle change now called the Palaeocene-Eocene Thermal Maximum. As the Chief Scientist on Ocean Drilling Program (ODP) Leg 208 and lead author on a 2005 Science paper, he showed how deep‐sea carbonate dissolution was influenced by a massive carbon release during the Palaeocene-Eocene Thermal Maximum. Zachos has been not only instrumental in generating crucial data for the Palaeocene-Eocene Thermal Maximum event, but also in the writing of ODP proposals to address the right scientific questions. He also compiled teams of people with complementary expertise to answer these questions.

His seminal work on a multi-site compilation of stable isotopes measurements throughout the Cenozoic resulted in an iconic graph, now known as the “Zachos curve”, which has become the standard view on climate change throughout the Cenozoic. His high-resolution measurements enabled the study of orbital variations showing clear eccentricity pacing of the carbon cycle and climate changes prior to the onset of Northern Hemisphere glaciations.
Through several ground-breaking contributions James Zachos fundamentally transformed our understanding of climate change throughout the Cenozoic and made a sustained impact within, and far beyond, the boundaries of palaeoceanography. His vision brought an entire Palaeogene community together and lifted it to carrying out unprecedented quality interdisciplinary research.