Time series of global, annual surface air temperature departures from the 1890-1919 average (the 0.0 line) from observations (black) and an ensemble of CCSM3 simulations (orange). The tan shading represents the spread of the individual ensemble members about the mean. Because CCSM3 is used to reproduce the climate of the past century, it is a very useful tool for understanding and determining the changes in the climate system that have driven the observed warming. Such simulations have revealed that the global surface warming of recent decades is a response to the increased concentrations of greenhouse gases in the atmosphere.

Priority 4: Developing Community Models

IPCC Scientific Contributions

Background

The Intergovernmental Panel on Climate Change (IPCC) was established by the World Meteorological Organization and U.N. Environment Programme during the 1990s to assess scientific, technical, and socioeconomic information relevant for the understanding of climate change, its potential impacts, and options for adaptation and mitigation. It is open to all members of the United Nations and the WMO. Three assessments have been released, the latest one in 2001. The Fourth Assessment Report (AR4) is due to be completed in mid-2007.

Progress

NCAR scientists were recruited during FY 2006 to contribute to the IPCC's AR4. The AR4 consists of three Working Groups. These groups will assess material from different disciplines and will cover a diversity of approaches to uncertainty, reflecting differences in the underlying literature. Below is a list of all NCAR scientists serving as authors for the AR4, listed by job title and Working Group number. In addition to scientific leadership, NCAR is providing vast amount of technical and computational support to the IPCC's AR4. Many other NCAR staff have supported this work by running computer simulations, supplying data, providing informal consultation among this wide range of activities. NCAR supplied 7 million CPU hours for climate reference and climate change simulations, amounting to 11,000 simulated years, for study and inclusion into the AR4. Over 100 TB of data was generated and is archived on the NCAR Mass Storage System.

Coordinating Lead Authors, Working Group I:
  • Guy Brasseur (Chapter 7),
  • Gerald Meehl (Chapter 10)
  • Kevin Trenberth (Chapter 3),
Lead Authors, Working Group I:
  • William Collins (Chapter 10)
  • Linda Mearns (Chapter 11)
  • Bette Otto-Bliesner (Chapter 6)
Contributing Authors: (as of September draft):
  • Julie Arblaster (Chapter 10)
  • Esther Brady (Chapter 6)
  • Guy Brasseur (Chapter 7)
  • William Collins (Chapter 2 and Chapter 9)
  • Aiguo Dai (Chapter 3)
  • Clara Deser (Chapter 3)
  • John Fasullo (Chapter 3)
  • Marika Holland (Chapter 8 and Chapter 10)
  • Jim Hurrell (Chapter 3)
  • Reto Knutti (Chapter 11)
  • Bette Otto-Bliesner (Chapter 9)
  • Dennis Shea (Chapter 3)
  • Kevin Trenberth (Chapter 1)
  • Tom Wigley (Chapter 10)
Coordinating Lead Author, WGII
  • Patricia Romero-Lankao (Chapter 7)
Lead Authors, Working Groups II and III
  • Linda Mearns (II, Chapter 2)
  • Kathleen Miller (II, Chapter 3)
  • Patricia Romero-Lankao (II/III, Cross-cutting themes of adaptation and mitigation)
Contributing Authors, Working Group II
  • Susanne Moser (Chapter 7)
Summary for Policymakers:
  • Guy Brasseur
  • Julie Arblaster
  • Reto Knutti
  • Jerry Meehl
  • Patricia Romero-Lankao
  • Kevin Trenberth
Technical Summary:
  • Julie Arblaster
  • Guy Brasseur
  • Reto Knutti
  • Jerry Meehl
  • Kevin Trenberth

Plans

The IPCC work will continue and be completed in FY2007 and NCAR researchers will remain actively involved with this project throughout FY2007. This research contributes to several of the NCAR Strategic Goals. Several of the NCAR Laboratories have Coordinating Lead Authors as well as Lead Authors contributing to the AR4. NCAR's involvement in this activity is generously funded by NSF.