ESRL Integrating Research and Technology Themes

Radiative Forcing of Climate by Non-CO2 Atmospheric Gases

  1. Goal and Scope
  2. The goal of this integrated activity is to foster greater collaboration, expand the breadth and improve the dissemination of information relating to NOAA's key role in evaluating the coupling between the non-CO2 atmospheric gases and radiative forcing of the climate system.

    The scientific focus is to:

    • Integrate evaluations of observed changes in global tropospheric ozone, their origins, and their implications for forcing of the climate system. This would provide prompt and greatly expanded examination and interpretation of tropospheric ozone trends, using observations as well as numerical models and laboratory chemistry studies.
    • Evaluate systematically all observed changes in halocarbons (HFCs, HCFCs, PFCs, and CFCs), methane (CH4), nitrous oxide (N2O), and other gases, and couple these to numerical model interpretation, as well as laboratory chemical findings, on a regular basis.
    • Extend climate reanalysis for the 20th Century using advanced data assimilation techniques as part of a strategy to better attribute causes for observed climate variability and change and, in particular, identify the roles of different forcing agents (e.g., CO2, CH4, N2O, O3, solar, aerosols, SSTs, land surface cover).
    • Collaborate with the Ozone Layer Recovery project to include stratospheric ozone trends in climate forcing estimations and projections.

    Such work has not been attempted in the past by any research group worldwide. Individual groups measure trends, while others conduct interpretive studies or lab studies, etc. Here, a fully coordinated approach would be carried out in a systematic way for the first time.

  3. Rationale and Payoffs
  4. Research over the last few decades has demonstrated that a variety of greenhouse gases play essential roles in forcing the climate system. Scientists at the Earth System Research Laboratory (ESRL) have been prominent among world leaders developing the understanding of this key issue. Their efforts have been integral to the quantification and demonstration of the magnitudes, changes, and processes influencing the roles of methane, halocarbons, and tropospheric and stratospheric ozone in radiative forcing. However, no broadly coordinated approach on these issues has been developed to date.

    ESRL researchers have also been world leaders in assessing and describing the pertinent policy-relevant findings on these issues, and they are looked to for a continuing leadership role in future national and international scientific assessments. Finally, this integrated approach will improve climate attribution research to assess linkages of radiative forcing agents to global and regional climate variations and change. The new approach described here would foster and broaden NOAA's research and the link to information products, providing decision-support of relevance to industry, governments, and the public.

  5. Major Collaborators and Their Research Foci
    1. Earth System Research Laboratory
      • Global Monitoring Division: Conduct regular observations of in situ trends in halocarbons, methane, nitrous oxide, stratospheric ozone, tropospheric ozone, and surface radiation at worldwide sites from Alaska to Antarctica.
      • Chemical Sciences Division: Develop and run numerical models for radiative forcing and gas-phase chemistry, laboratory studies, and in situ global tropospheric chemistry process field studies needed to link sources to radiative forcing.
      • Physical Sciences Division: Perform climate analyses obtained by assimilating observations into state-of-the art models as an essential component of an end-to-end climate observing system.
    2. Other NOAA
      • Geophysical Fluid Dynamics Lab: Numerical modeling of coupled radiative transfer/ climate feedbacks and processes.
      • Office of Global Programs: Focused projects that couple intramural and extramural partners.
      • NESDIS and NWS: Satellite observations and data sets of stratospheric ozone and temperatures.
    3. Others
      • CIRES: Fully integrated contributions to all aspects of the program.
      • NASA: Airborne field studies of greenhouse gas processes and partnership programs for monitoring of radiatively important atmospheric species.
  6. Contributions to NOAA Goals
    • NOAA Strategic Plan FY 2005 - FY 2010. Performance Objective: "Reduce uncertainty in climate projections through timely information on the forcings and feedbacks contributing to changes in the Earth's climate." (p. 8)
    • NOAA Climate Goal (Program) FY 2006 Program Baseline Assessment (PBA), Climate Forcing Component. Performance Objective: "Provide timely adequate information on the climate roles of radiatively important trace atmospheric species (e.g., fine-particle aerosols and ozone) that is needed to broaden the suite of non-carbon options available for policy support regarding the climate change issue." (p. 69)
    • OAR Strategic Plan: FY 2005 - FY 2010. Research Outcome: "Timely information on radiative forcing by non-CO2 greenhouse gases, with special emphasis on short-lived species such as tropospheric ozone." (p. 10)
  7. Major Information Products, Customers, and Linkages
    • Annual Report (Part of a potential "State of the Atmosphere Report") Trends of atmospheric greenhouse gas concentrations and radiative forcing, with commentary. Updated Global Warming Potentials. Distribution via web and other mechanisms to governments and industry.
    • Intergovernmental Panel on Climate Change (IPCC). Authoritative state-of-understanding assessment of climate change, which is used by decision makers nationally and internationally with regard to the climate issue. The Fourth Assessment Report (2007) is underway. The NOAA linkages include co-Chair of the Climate Change Science Working Group, chapter authors and contributors, and reviewers. NOAA ESRL scientists have played leading roles in these important reports since 1994.