Welcome to CCR's Paleoclimate
Welcome to CCR's Paleoclimate in CGD
Paleoclimate Research
Paleoclimate Research is a research area within the Climate Change Research Section (CCR) of the Climate and Global Dynamics (CGD) Division at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado.
Paleoclimates offer a unique perspective to understand both the Earth's climate sensitivity and stability. NCAR climate models have been used to study past natural variability of the Earth system since the 1970's with the pioneering work of Jill Williams, Eric Barron, John Kutzbach, and Warren Washington. The development of a coupled climate model, the Climate System Model (CSM), in the 1990's included a lower resolution (but otherwise equal) version of the model, PaleoCSM, which was particularly useful for the long simulations required to study past climates. PaleoCSM was successfully used to study mechanisms responsible for changes in the coupled climate system and to determine associated magnitudes of changes for various climatic variables. Simulations covered a large range of applications, including the last millennium, Holocene ENSO, the Last Glacial Maximum, Eocene, and Cretaceous. These simulations highlighted the importance of considering feedbacks among the atmosphere, ocean, land surface, and sea ice in establishing the magnitudes of past climate change to changes in past forcings. These simulations not only acted as a benchmark for CSM but allowed testing of various hypotheses of mechanisms to explain proxy records of past climate change.
This figure shows annual air temperature simulated by the NCAR Community Climate System Model (CCSM3) for four different past time periods: a warm period approximately 250 Mya - the Permian-Triassic, a period of abrupt warming approximately 55 Mya - the Paleocene-Eocene Thermal Maximum, a glacial period approximately 21 kya - the Last Glacial Maximum, and a cold period approximately 500 years ago - the Little Ice Age. This image illustrates the large range of climates under natural forcings. A comparison of the CCSM3 simulations with geologic data confirms that this model captures the magnitudes of change about right justifying its use of future climate projections.