Palaeoclimatology is the study of past climates, typically extending from thousands to millions of years ago, and it is an essential aspect of understanding current and future climate changes. Since direct measurements of temperature, precipitation, and other meteorological parameters only go back a few centuries, scientists rely on indirect evidence, known as palaeoclimatic proxies, to reconstruct the Earth’s ancient climate. These proxies are derived from natural archives that preserve climate signals over long timescales. The interpretation of palaeoclimatic data is fundamental for building models of climate variability, understanding natural climate cycles, and assessing the anthropogenic impact on the climate system. There are several key sources of palaeoclimatic data, each with its strengths and limitations. These include ice cores, tree rings, sediment cores (from lakes and oceans), corals, speleothems (cave deposits), pollen records, and historical documents. The reliability of these sources depends on their resolution, geographic coverage, dating accuracy, and sensitivity to specific climatic parameters. Below is a detailed explanation of the primary sources of palaeoclimatic data: ### 1. Ice Cores Ice cores are cylindrical samples drilled from ice sheets and glaciers, especially in Greenland and Antarctica. These ice layers accumulate annually, trapping air bubbles, dust, volcanic ash, and isotopes of water, providing a year-by-year or even seasonal record of past climates. The isotopic composition of the water molecules—particularly the ratio of oxygen-18 to oxygen-16 (δ18O)—is a well-established proxy for past temperatures. Higher δ18O values typically indicate warmer periods. Moreover, trapped air bubbles in the ice contain ancient atmospheric gases, such as carbon dioxide (CO₂) and methane (CH₄), which provide direct evidence