Lämpötilahistoria

Lämpötilahistoria refers to the study of past temperatures, primarily focusing on changes in Earth's climate over geological time and human history. This field draws on various sources of evidence to reconstruct past thermal conditions. Instrumental records, such as thermometer readings, provide the most direct evidence but only extend back a few centuries. For longer timescales, scientists rely on proxy data, which are natural archives that record environmental conditions.

These proxies include ice cores, which trap air bubbles and isotopes from past atmospheres, allowing for the reconstruction of atmospheric composition and temperature over hundreds of thousands of years. Tree rings offer annual resolution of past climate, with their width and density influenced by temperature and precipitation. Sediment cores from ocean floors and lakes contain fossilized organisms and chemical signatures that reflect past water temperatures and climate patterns. Stalagmites and stalactites in caves can also provide temperature information through isotopic analysis.

The analysis of lämpötilahistoria reveals significant fluctuations in Earth's temperature throughout its history, including periods of intense glaciation (ice ages) and warmer interglacial periods. More recently, human-induced climate change has become a central focus, with instrumental and proxy data showing a clear warming trend in the last century, largely attributed to increased greenhouse gas emissions. Understanding past temperature trends is crucial for contextualizing current climate change and projecting future climate scenarios.