There are many scientists that study the environment, so there isn't one single name for them. Here are some common titles depending on their area of focus:

* Environmental Scientist: This is a general term for someone who studies the environment, including its physical, chemical, and biological components.

* Ecologist: Focuses on the interactions between organisms and their environment.

* Geologist: Studies the Earth's physical structure, composition, and processes.

* Meteorologist: Studies weather and climate.

* Oceanographer: Studies the ocean and its inhabitants.

* Biologist: Studies living organisms and their interactions.

* Chemist: Studies the chemical composition of the environment.

* Physicist: Studies the physical laws governing the environment.

The specific title will depend on the scientist's area of specialization.