What are the qualifications to become a biologist that performs research on the environment?

In general, you will most likely need a PhD, or at least a master's degree in a Biological or Environmental Science. Many universities offer these programs. You will need to research these in your area. Not all universities offer graduate programs, so ask about that, too.

Your undergraduate degree will likely need to be either in Biology, Chemistry, Environmental Science, or Public Policy.

Environmental Science is a very hot field right now, and prospects are good for employment. Most positions will be in the government, which are stable, but not necessarily high paying (but can be very rewarding).

After working for a government for a few years you may have the opportunity to move into the private sector in Environmental Consulting firms, where the pay will be higher, but the hours longer, and possibly have less satisfying work.

Think more about what exactly you might want to do, ask your teachers and parents for advice, and go for it.