Environmentalism is no longer a fad, but an established movement with widespread popularity. As a result, environmental consulting has become extremely profitable, especially for startups and small businesses who offer a "one-stop" shopping experience for customers. According to Inc. environmental consulting is a $19.1 billion industry that  continues to grow.

Even startups with a specific environmental niche can profit. By focusing on one area like renewable energy, they can provide their services to certain geographical areas that large companies cannot cover and maintain competitive prices.

As the environment changes so does field of environmental consulting, providing new opportunities for entry and specialization. "A huge thing right now is natural gas, particularly the Marcellus Shale in Pennsylvania and New York," Mauer says. "That is kind of the Wild West because there's so much exploration right now." Disaster recovery, from both natural disasters like Hurricane Katrina or man-made like the BP oil spill, has also become a new trend in environmental consulting in recent years.

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