Paleoclimate reconstruction relies heavily on geochemical proxies preserved in marine and terrestrial archives. Oxygen isotopes (δ¹⁸O) in foraminiferal calcite are key indicators of past temperature and global ice volume, with higher values typically indicating cooler periods. Carbon isotopes (δ¹³C) reflect changes in the global carbon cycle, ocean productivity, and ventilation. Mg/Ca ratios in foraminiferal shells serve as robust paleothermometers, with higher ratios indicating warmer sea surface temperatures. Sr/Ca ratios, Ba/Ca, and Li/Mg are also used to infer temperature and salinity changes. Additionally, trace elements like Cd/Ca or Zn/Ca can indicate nutrient levels and ocean circulation patterns. When used in combination, these proxies enable high-resolution reconstructions of Earth’s climate history, providing crucial insights into past climate dynamics and aiding predictions of future climate scenarios.