Analysis of the geologic record shows that Earth’s temperature raised suddenly, and plunged precipitously, many times in its history. These abrupt climate transitions presumably occurred because tipping points in the climate system were exceeded. What is the nature of these tipping points? About 34 million years ago one of these abrupt changes occurred, when Earth's climate shifted from a relatively ice-free world to one with glacial conditions and substantial ice sheets on Antarctica. How global climate and the ocean’s temperatures at surface and in the deep changed during this climate transition remains poorly understood, and evidence for the development of Northern Hemisphere polar ice sheets is controversial. The goal of CLImBP is to investigate this climate transition through the application of the new and powerful paleo-thermometer: clumped isotopes in carbonates. CLImBP will apply this method on benthic and planktonic foraminifera from samples across Eocene-Oligocene climate transition and accurately reconstruct changes in sea-surface and deep-sea temperatures. These reconstructions will be used to test climate model simulations of this transition and improve our understanding of tipping points in the climate system, which is important for the comprehension of modern global climate change.