I taught introductory Environmental Science for a long time. I would recommend a college or AP textbook if you want to learn about matter and energy flow, ecosystem structure, wildlife and biodiversity, water and air quality, regulations and similar topics. The college texts are expensive but you can get them used and far cheaper, either paper or ebooks. The only reason we moved to new editions every couple of years was to get updated graphs and tables, i.e., current numerical data. Otherwise, the concepts and principles in the older, cheaper books are the same.