Paleoclimate: A History of Change
Scientists study paleoclimate to learn about Earth’s history and to understand current climate change, including the biological implications.
Key Concepts
- Weather describes short-term changes in atmospheric conditions such as temperature, precipitation, wind, cloud cover, and so on. Weather can describe events taking place over periods as short as minutes to as long as weeks or months and can cover areas from extremely local to entire regions.
- Climate describes patterns of weather conditions over periods of time of a season or longer. Regional climate varies widely on Earth from rain forests to desert, and tundra to savannah.
- Scientists studying global climate often use averages that may mask dramatic regional differences but are useful to observe trends and make predictions.
- Ocean temperature is a common proxy for global climate because the ocean is an enormous heat reservoir and plays a dominant role in global climate patterns. Differences in ocean temperature therefore correspond to differences in global climate.
- While both climate and weather patterns vary over time, the term climate change refers to a departure from preceding patterns.
- Earth’s climate is complex and dynamic. Two factors had a dominant influence on Earth’s climate over geologic time: the amount of solar radiation directed at the planet; and the composition of Earth’s atmosphere.
- Atmospheric composition affects climate through the concentration of greenhouse gases, which include carbon dioxide (CO2), methane, and water vapor. CO2 is of special interest because it stays in the atmosphere for a long time and the concentration varies significantly over geologic timescales.
- While Earth’s climate has fluctuated, the natural patterns of change are very slow. The release of carbon dioxide by humans since the start of the Industrial Revolution has caused alarmingly rapid climate change that far exceeds the rate of change during any time since human evolution.