Outside of an extremely left-wing or academic setting no one has heard the term "environmental racism". It's also not nearly as self-explanatory as people think because it's an intentional effort to racialize things we can explain straightforward without buzzwords.

It's not difficult to say that the problems with climate change will disproportionately affect the poor and marginalized communities of America. Those communities are disproportionately non-white do to systemic racism. People can understand that just fine.

"Environmental racism" is an abstraction and doesn't make the previous point clear because many people could interpret it in a number of different ways including as intentionally racist schemes which may or may not exist. In fact, that's the trend in woke academia.

The way we view systemic racism is no longer about how an unequal system was built on the legacies of slavery and Jim Crow, but it is rather an intentional goal of white supremacy that's ongoing. This is of course more ideological than empirical as views on race have improved.

What we haven't done is much to change the material conditions for the lower classes compared to the upper classes. If anything, since Reagan and Clinton finished the neoliberal revolution that inequality has increased. The only way we can end systemic racism is undoing that.