The response of the hydrological cycle to temperature changes in recent and distant climatic history

The relationship between the hydrological cycle and the temperature is rather complex and of great importance to human socioeconomic activities. The prevailing theory suggests that as temperature increases the hydrological cycle is intensified. Practically, this means more and heavier precipitation. However, the exact magnitude of hydrological cycle response and its spatio-temporal characteristics is still under investigation. Looking back in Earth’s hydroclimatic history, it is easy to find some periods where global temperature was substantially different than present. Here, we examine some of these periods to present the current knowledge about past hydrological cycle variability (specifically precipitation), and its relationship to temperature. The periods under investigation are the Mid-Miocene Climate Optimum, the Eemian Interglacial Stage, the Last Glacial Maximum, the Heinrich and Dansgaard–Oeschger Events, the Bølling–Allerød, the Younger Dryas, the 8.2 ka event, the Medieval Climate Anomaly, and the Little Ice Age. We report that the hypothesis that a warmer climate is a wetter climate could be an oversimplification, because the response of water cycle appears to be spatio-temporally heterogeneous.