Paleokliima

Paleokliima refers to the study of Earth's past climates and their variability before modern instrumental records. It encompasses climate conditions from millions of years ago to more recent centuries, reconstructed from indirect evidence preserved in rocks, sediments, ice, and biological remains. The goal is to understand the range of natural climate states, the drivers of past change, and how different components of the climate system interact.

Researchers rely on proxies such as ice cores, marine and lake sediments, speleothems, pollen, fossils, and tree rings. Isotopic data (for example, oxygen-18 and deuterium) and chemical ratios (such as Mg/Ca in foraminifera or alkenone unsaturation) provide estimates of past temperatures, ice volume, precipitation, and atmospheric composition. Radiometric dating and stratigraphic correlation place these records in time, while multi-proxy syntheses integrate signals into broader regional or global climate reconstructions.

Notable intervals studied include the Last Glacial Maximum, periods of deglaciation, and Holocene fluctuations such as the Medieval Warm Period and the Little Ice Age. Longer records reveal greenhouse climates of the Cretaceous and Eocene and major transitions linked to orbital forcing and tectonics.

Paleokliima research informs our understanding of natural climate variability, helps constrain climate sensitivity, and tests climate models used to project future change. It also clarifies feedbacks and thresholds in the climate system and provides a longer-context baseline for interpreting contemporary trends.