I applied to Columbia M.S. in Sustainability Management for the spring term and heard back in 4 or so weeks. I got the impression that they review applications relatively quickly, and the admissions office is quite flexible.
I ended up deferring my admission to fall 2021, which was also easy to do. They don't offer any merit based aid because, as they said, "the program is available part-time, so students can work." They do have some funding opportunities such as Fellows programs, assistantships, and internships, but I'm pretty sure not everyone can get those. Still even if you do, most of the tuition cost falls on students.