My naive impression is that the safest bet for survival would be to improve our technological mastery to a point where we can create near-closed and self sufficient ecosystems for small populations that they can be fully in control of, like deep space habitats. Such habitats should be able to support life inside indefinitely and be able to produce new habitat. And we need to make sure that we can maintain a high level of technological competence even if our population would be severely diminished. Perhaps then can civilization survive almost anything. Not sure if this is a pipe dream.