Robust flux estimates of greenhouse gases (GHG, here defined as CO2, CH4 and N2O) require comprehensive, multi-year and interlinked measurement and data analysis activities in all domains (atmosphere, ocean and biosphere), reflecting the uncertainty and variety of sources that determine the trend and variability of atmospheric concentrations of GHGs. Detailed knowledge of the temporal and spatial distribution of anthropogenic and biospheric GHG emissions is vital for understanding, attributing and managing sinks and sources. In the terrestrial biosphere, sinks and sources are dynamic, and distributed at a range of spatial scales across mosaics of managed and semi-natural ecosystems, with varied temporal sensitivities to weather and management. The oceans serve as major repositories of anthropogenic carbon, but the rate of this uptake at the sea surface varies substantially on annual and decadal time scales.

This session invites contributions that make connections across different domains, sub-disciplines and scales. They can include, but are not limited to, topics like:
- the temporal and spatial distribution of GHG sources and sinks
- linking GHG measurements over multiple scales, from individual sites to regional or global scales
- modelling studies that connect multiple scales and domains
- using large-scale atmospheric and remote sensing observations and models to improve top-down estimates of GHG emissions
- integrating oceanic and atmospheric observations and/or models
- understanding why and how air-sea fluxes of GHGs vary regionally, seasonally and multi-annually in key areas such as the North Atlantic Ocean
- understanding the sensitivity of biospheric GHG fluxes of natural, semi-natural and managed ecosystem to climatic factors and management practices
- improving uncertainty estimates of GHG fluxes, sources and sinks
- development of new techniques, new instrumentation and new observation networks for GHG measurements in atmosphere and ocean