What's the difference between the brine/solid leftovers and sea salt you buy at the store? I tried googling but not finding much.

I'd assume that people working on this are looking for alternative uses for the leftover material both for ecological reasons but also to help generate more money from the process.

For second I thought you spelled Colombia wrong and then I realized it's not the country. It's just very similar shape.

If it's not coastal flooding, it's inland flooding from heavy rainfall or droughts or "crazy" storms both summer and winter or fires or heat waves and whatever mother nature can cook up. No area is safe from climate change.