Terrestrial primary productivity indicators for inclusion in the National Climate Indicators System

The National Climate Indicators System (NCIS) aims to provide a suite of systematically updated, easily interpretable, and policy relevant national metrics of key physical, ecological, and societal conditions. The NCIS will distill and communicate complex scientific information to a broad audience as part of sustained National Climate Assessments. The current NCIS has made significant strides in defining its scope, providing an initial suite of indicators, and outlining its future development goals. In line with the scope and aims of the NCIS, we present a set of terrestrial primary productivity indicators that are scientifically defensible, scalable, directly related to climate, nationally important, built on existing agency efforts, and linked to the conceptual framework of the NCIS. The Gross Primary Productivity (GPP) and Net Primary Productivity (NPP) indicators provide seasonal and annual metrics of the growth of all plant material across the contiguous U.S., Alaska, Hawaii, and Puerto Rico. The GPP and NPP products used to produce the indicators have become key carbon measurements of environmental health and ecosystem services, including food, fiber, and fuels supporting national economies, human sustainability, and quality of life. We demonstrate how the proposed GPP and NPP indicators are relevant across indicator system sector topics of Forests, Grassland/Rangelands/Pastures, Agriculture, Wildfire, and Seasonal Timing and Phenology, can be used in concert with existing proposed indicators, and will aid to filling current gaps in the NCIS.