Despite only launching in 2013, TripAdvisor’s GreenLeaders sustainable hotel program has already become the largest such scheme in the world. Such scale and a business model based on big data have enabled it to present some pretty attractive statistics in favour of greening accommodation. Research conducted by Harvard and Cornell universities found that offering sustainable food options drove on average a +0.4 point increase in a hotel’s five point TripAdvisor rating. Furthermore, properties score on average 20% higher in their TripAdvisor rating than non-GreenLeaders hotels. With nearly 8,000 properties already signed up in 21 countries, GreenLeaders may soon be one of the biggest drivers for sustainable tourism hitting the mainstream.