Staying fit = staying in good shape, mentally/physically, or something like that.
Being fit for a purpose = being good enough for that purpose.
I was wondering about the German fit in klimafit and whether it meant the usual kind of "fit" as in "Opa ist noch fit" or if it was a more recent borrowing from English, based on "Fit for Future". I wasn't thinking of using the English word "fit" in the translation.
Climate-proof is probably the right direction I guess.
If you needed to cover preparation and mitigation, you could potentially also use the vaguer "action plan":
The Climate Change Action Plan lays out a clear course of action for Mississauga over the next ten years and includes goals to both mitigate and adapt to climate change https://www.mississauga.ca/projects-and-strat...
a three-year action plan was developed to illustrate the opportunities available to address the Climate Emergency and start the council’s journey towards reducing emissions. https://www.redbridge.gov.uk/about-the-counci...