Tourism generates 11 percent of global gross domestic product (GDP), employs 200 million people and transports nearly 700 million international travelers per year; a figure that is expected to double by 2020. It is considered one of the largest, if not the largest, industries on the planet. With nature and adventure travel one of the fastest-growing segments within the tourism industry, the Earth's most fragile, high biodiversity areas are where most of that expansion will likely take place. While tourism has the potential to provide opportunities for conserving nature, tourism development, when done improperly, can be a major threat to biodiversity. - from
crumb trail