What a great picture. Comments above are somewhat misguided. Green roofs do the following: - increase lifespan, filter water and air pollution, stabilise building temperature, cool roof, create habitat, etc etc.
Yes there are poor installations by bad contractors, but they are hardly 'enviro-lunancy' when you look at the full economics

Bizarre industry. Rule #1 plants take water. Rule #2 water on roofs or in buildings leaks. If not now, later. Rule #3, plants attract bugs. Rule #4, bugs don't stay in gardens. So what has been made is a mess. Reminds me of the huge indoor pond, bronze fish and bronze bear in the central lobby of the CA State Building in downtown Los Angeles. The pool is empty. Why? It was leaking into the underground garage underneath. Oops. More water, more mess, more maintenance.

I'm a roofer who has had to deal with these types of roofs and they are insanely expensive, hard to keep up, and end up being more of a trouble than they are worth. Another example of short sighted enviro-lunacy.