Abstract: Fortran is, by some measures, 70 years old this year yet it continues to contribute enormously to many scientific and engineering disciplines around the world. The Fortran ecosystem (broadly defined) is perceived by many outside it as old and out-dated, and therefore comprising a portfolio of legacy systems. Yet the latest revisions to the language standard were agreed and published in 2023, there are an increasing number of tools to support Fortran software engineering, and many teams are modernising their Fortran codebases to leverage modern hardware. It therefore appears that the international Fortran ecosystem is being pulled in different directions: simply put, to invest in Fortran or to divest from it. A further complication is that the ecosystem appears fragmented and disconnected. Thus, whichever direction one turns and proceeds – to invest or divest – there is enormous risk, with the additional challenge of securing considerable targeted investment of resources and effort over an extended period of time. In this interactive workshop, we will share results from a recent survey of the international Fortran ecosystem, present our plans for a recently-funded, three-year EPSRC Network+ project on the future of Fortran-based science and engineering, and use those two items to stimulate discussion on the following question: How do we sustain scientific and engineering disciplines currently dependent on Fortran so that they continue to advance knowledge – and contribute to society, the economy and the environment – for the next 70 years?