''The diminished quality of our planet's air affects not only human health but has wide impacts and implications on vegetation and, equally importantly, influences climate change. When the first Earth Observing satellite sensors were launched, maps of pollutant concentrations revealed -on a global scale- the most affected regions, the contribution of individual emitting sectors, the magnitude of regional and inter-hemispherical transport of pollution. The continuity in space-born monitoring instruments, and the endless improvement on the observing instrumentation, provided the ever-increasing proof that monitoring human activities over the whole planet is absolutely necessary for identifying and mitigating humankind’s intervention on the Earth. 

In later years numerous EO air quality-related observations have been assimilated in chemical transport models, in air quality forecasting systems, in real-time air quality monitoring algorithm chains, for the betterment of society as a whole. Even more recently, the advancements in computational technology have driven the scientific community to seek solutions based on Artificial Intelligence so as to bridge the remaining gaps between monitoring the Earth from space and the situation near the ground, within the air we breath and live in. 

In this keynote speech, we shall move from the past into the future following the journey that space-born Earth Observations of air quality markers have made, highlighting the significance of the contribution of ESA to the major international agreements and treaties on air pollution and climate change and concluding by identifying possible future pathways in space exploration for healing of our continuously warming planet.''

''To limit global warming to well below 2^oC compared to pre-industrial levels requires a decarbonization of the economy and many countries have pledged to reach net–zero emissions by 2050 but progress has been slow so far. Satellite observations of CO2 and CH4 will play essential for tracking progress towards emission reduction targets, and for verifying the effectiveness of mitigation policies. Satellites also provide information on natural land and oceanic sinks which store vast amounts of carbon and which will play an important role in the pathway towards the goals of the Paris agreement. 

In this presentation, the key concepts for satellite observations of CO2 and CH4 will be introduced and examples how we use current, dedicated satellite missions to diagnose and quantify regional surface fluxes of natural and anthropogenic sources will be presented. We will show how data from these dedicated missions can be complemented by hyperspectral satellites that measure with very high spatial resolution so that individual emission sources can be observed. The presentation will end with an outlook to upcoming missions such as the Copernicus CO2 Monitoring (CO2M) Mission that are designed with the aim of monitoring anthropogenic emissions.''

Discussion and Recommendations for upcoming Sentinel User Preparation Activity – Atmosphere Science Foundational Experiment

''Lidar depolarization sensitivity can be leveraged for aerosol typing and discrimination of desert dust in aerosol mixtures. In the talk, the progress on dust profiling from ground and space will be presented along with its applications on estimating the dust impact on radiation and cloud formation. Furthermore, the impact of dust profiling assimilation is discussed for atmospheric composition and NWP applications. Finally, suggestions are given on how to leverage over the past, current and forthcoming lidar space missions to construct a 3D climate data record for desert dust.''