Efficiently searching Google for technical reports, white papers, and other documents means constructing your search out of three elements:
For example: "deforestation," "ocean plastic pollution," "agricultural methane," etc.
Where are you primarily interested in studying this problem? Some examples might be "Amazon rainforest," "north Pacific ocean," "Central Africa," "St. Joseph County, Indiana"
Are you looking for white papers, resolutions or policies from local government bodies, management plans, environmental impact statements, etc.?
deforestation AND Amazon rainforest AND environmental impact statements
ocean plastic pollution AND north Pacific AND white paper
industrial development AND St. Joseph County Indiana AND county council resolution