It is a 6-digit number assigned by Visa to each acquirer. If a merchant has different acquirers for Authorization versus Settlement, the merchant will have a separate BIN for each one. SIGIS is only collecting the Authorization Acquirer BIN at this time.
Carbon is the basic building block for all forms of life on Earth. Fortunately, carbon is also one of the most abundant elements on our planet. Like all matter, carbon can neither be created nor destroyed, and so all living organisms must find a way to continually reuse the finite carbon supply that is available.
Anyway, the likely reason that green is important is that plant life was a very large part of what we needed to look at for a very long time, and the same for the ancestors of humanity. If you live in a suburb it might be hard to notice, but the natural world is almost entirely green when viewed from a distance.