According to an interesting new article in Business Week by writer Douglas McMillan, a growing number of midlife career-changers are ditching their corporate gigs to pursue careers devoted to the environment.

There are currently 8.5 million of these "green-collar jobs" in renewable-energy and energy-efficiency industries in the U.S. and a November report commissioned by the American Solar Energy Society projects that number could grow to 40 million by 2030.

Interested in pursuing a green career? Here are some resources to get you started:

• Green Careers Guide from MonsterTRAK
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• Green Career Salary Trends at Payscale.com
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• EnvironmentalCareer.com Job Board
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• Green Career Tracks Coaching and Services