Look at the curriculums of each because they will be different - same response as your other.
UCSD has Environmental Systems with four tracks - Earth Science, Ecology Behavior & Evolution, Environmental Chem, and Environmental Policy (which is likely more like Studies than Science).
UCR has focus in these areas -oil Sciences ,Hydrologic Sciences , Atmospheric Sciences, Environmental Toxicology, and Environmental Management.
Most of UCSC faculty is from marine sciences and earth sciences.
Dig into curriculums - and find the right schools.
And you’re in CA - but there’s also WUE that you have access to - to keep costs low and great merit at top OOS schools in the major - like UMN.
Especially since grad school is likely, find the right program for you…not a rank. Find the schools with the focus area of interests is what I think.
My son is a UC Davis graduate of their Environmental Science and Management program. UC Davis has several Environmental Science degrees and Emphasis tracks. You are welcome to PM with any questions.
Any particular emphasis that he is interested in pursuing?