Apparently a nation's maximum environment rating is 11.00 , before Global Radiation Level (GRL). The maximum environment rating you can attain after GRL is equal to (11.00 - GRL). You can find your current environment rating by highlighting the screen next to your environment stars.
Example: If the GRL is 4.00, then the maximum environment rating you can possibly attain will be (11.00-4.00=7.00). Which means, if your environment rating is at the max, it might be useless to try to improve your environment any further.
I apologize for re-posting an environment thread, but the previous thread was not explained well enough for me. I don't understand "1+ GRL" when no one says where the 1 came from or what GRL means. My explanation here is what I can gather from the mess of information contained in the previous threads. I hope this helps those out there that were as confused as I was. Thank you.