Megan Epler Wood, the director of the International Sustainable Tourism Initiative at the Harvard School of Public Health, says there’s “no question” that sharing existing city space is good for the environment. The demand to build new hotels is incredibly high, according to Epler Wood, given that tourism is growing at twice the rate of global GDP. Home sharing can negate the need for so many new hotels, and thus mitigate the harmful effects that superfluous construction has on the environment. Epler Wood, who rents a room in her own house through Airbnb, believes that the sharing economy can generate a more distributed form of income for areas that previously didn’t benefit from tourism. “The biggest change about renting a room in your home through Airbnb is that you don’t have to market at all,” says Epler Wood,