Long Term Monitoring of Greenhouse Gases at NOAA—a Fifty-plus Year Record (Invited Presentation)

NOAA's Earth System Research Laboratory and its precursor organizations have been monitoring trends and distributions of greenhouse gases and other climatically relevant constituents in the atmosphere for over 50 years (http://www.esrl.noaa.gov/gmd). The focus of these measurements has been to obtain reliable records of global trends and distributions of atmospheric composition, but their use and experimental design have advanced over time with evolving scientific questions. In earlier days, questions focused on global issues and products were global in nature. Later, they began to address intra-hemispheric properties, continental contributions, and overall large-scale sources and sinks (e.g., http://CarbonTracker.noaa.gov). Today, and into this century, scientific questions continue to progress and the observation systems with them. Critical questions likely will center on greenhouse gas emission reduction efforts, ecosystem feedbacks, and so-called “tipping points”. Regional information will become increasingly critical to supporting greenhouse gas emission reduction efforts, yet this information must be accurate, precise, and without bias. With emerging diverse, regionalized efforts to monitor greenhouse gases, compatibility of measurements and measurement systems becomes more important than ever. This presentation will identify major, climate-relevant findings that have come from NOAA's networks and those of others over the past several decades and will address the long-term monitoring needs to support decision-making over the next decades as society begins to seriously address climate change.