He is a geochemist who studies Earth’s past climate. He has led many drilling expeditions of the International Ocean Discovery Program (IODP) and field excursions to collect marine and lake sediment cores and speleothems for palaeoclimate reconstructions. His research has demonstrated how past climate change affected ancient civilisations, such as the Maya and Indus Valley. Research by Hodell, Brenner, Curtis and Guilderson was instrumental in rethinking the Maya Collapse.[3] Climate data derived from core samples retrieved from closed lake systems in the Mexico's Yucátan and Guatemala showed a period of extensive drought. In 1995, Hodell, Curtis and Brenner published a paleoclimate record from Lake Chichancanab on the Yucatán Peninsula that showed an intense, protracted drought occurred in the 9th century AD and coincided with the Classic Maya collapse. He has also made key contributions to understanding the Ice Age cycles of the Quaternary and their relationship to Earth’s orbit—for which he was awarded the Milutin Milanković Medal of the European Geophysical Union. More recent work has focused on the causes of rapid (millennial) climatic changes during the Quaternary using the extraordinary sedimentary archive preserved below the seafloor of the Iberian margin