Weather phenomena are one of the biggest causes for significant delays and unpredictable disruptions within air traffic management (ATM) network operations. The changing global climate increases the future severity and frequency of these air traffic disturbing weather phenomena. This deteriorates the predictability of 4D trajectory ATM network planning and potentially increases the delays within air traffic operations. Furthermore, aviation itself has a responsibility to mitigate its climate impact, improve the long-term sustainability of the ATM operations and contribute to the global effort towards the reduction of anthropogenic climate change. The SESAR2020 Exploratory Research project CREATE developed a new Concept of Operations (ConOps) aiming to tackle this problem, proposing an integrated trajectory optimisation framework to tactically define environmentally-scored optimised 4D trajectories, for a multi-aircraft airspace configuration, using advanced numerical weather prediction models, combined with air traffic control (ATC) driven demand-capacity balancing methods. The optimised trajectories aim to evade thunderstorms and contrail formation regions, whilst minimising CO2, non-CO2 and local air quality impacts.