Pub. date: 2008 | Online Pub. Date: April 25, 2008 | DOI: 10.4135/9781412963893 | Print ISBN: 9781412958783 | Online ISBN: 9781412963893| Publisher:SAGE Publications, Inc.About this encyclopedia
Detection of Climate Changes
Petra A. Zimmermann & Jill S. M. Coleman
BECAUSE THE ATMOSPHERIC systemisdynamic, variations in temperature and precipitation regimes have occurred throughout the Earths history. Glaciations and déglaciations, for example, show how changeable climate can be. Detecting climate changes shows that climate differs significantly from some previous episode. Detection differs from attribution, which denotes the causes of those changes. While daily fluctuations in weather happen as a consequence of a chaotic atmosphere; climate fluctuations, based on smoothed aggregations of weather events, represent significant shifts in the longer-term averages. To discern these shifts, numerous techniques and methods are employed. Climate changes, which occur at a variety of temporal scales, are assessed using both directly-observed and proxy data. Directly-observed information refers to meteorological and climate-related variables that have been directly evaluated, such as temperature measured by a thermometer, or cloud tops captured by satellite imagery. Directly-observed data have been used to chart recent increases in air temperature and carbon dioxide (CO ...