Is there a career that combines aerospace engineering and environmental science?

Two areas where aerospace engineering directly overlaps with renewables are (1) wind energy and (2) renewable batteries. On the first, aerospace engineers develop a deep understanding of fluid dynamics, which is very applicable to designing wind turbines. Many aerospace research programs have groups that work on wind energy. On the second, aerospace engineers also work on making lighter and more efficient batteries, which can save fuel, lighten the plane and decrease CO2 consumption.

Hope that helps and best of luck!

Another area of overlap is in the area of hydrogen storage, production, and uses. Although the practical applications of hydrogen in conjunction with renewable energy are still in the infant stage (fuel cell vehicles, reversible energy storage, combustion power cycles), the use of hydrogen will be necessary in many applications where fossil fuels need to be replaced such as in longer-range transportation or heavier duty than what can be accomplished economically/efficiently with electrical vehicles. The engineering challenges in the hydrogen industry are enormous and are exciting for a young engineer seeking to solve hard issues.

My background is not in aerospace; however, renewable energy, sustainability, and climate change are issues that are driving many new employment opportunities across a wide range of engineering disciplines. NASA, NOAA, Dept. of Energy, may offer direct opportunities for those interested in aerospace and the environment (satellites, remote environmental data measurements, assessment, modeling, etc.), as well as firms that do contract work for these agencies. You are pursuing a great academic focus that will evolve as you advance through your studies, so don't worry about a specific position/role at this point. The fundamentals you will get through your education will apply to a wide range of opportunities. Too many people go after a career for money or status and wind up very unhappy. Follow your passion and do what makes you happy - that understanding will come in time.