The official version of the Holy Father’s encyclical on the environment, Laudato Si’, is available HERE.
You can order it on Amazon HERE, though it looks like it is out of stock at the moment.
I haven’t read the encyclical yet. I am going to try to find a PDF version, and transfer it to my Kindle to read. Reading that long on a text on a backlit screen is a bit hard on my eyes 🙂
[EDIT – the PDF version is available off the same page -> HERE]
As always my advice is – read it for yourself.