Extreme weather events such as severe rainstorms cause sewer systems to overflow, releasing millions of gallons of untreated sewage water into homes and businesses.
Tree planting is perhaps the job on this list that requires the least amount of expertise: Anyone can buy a sapling, plant it in their backyard, and help it grow.
Wildlife experts in the National Parks Service and private organizations are coming up with increasingly creative measures to control the spread of invasive species.
Repairing buses or performing maintenance on the subway may seem like a mundane job, but it is vital to helping millions of Americans live more sustainable lifestyles.
These roles may change from traditional clerical duties to include more work with large-scale environmental data, communication, and grassroots organizing.