This document discusses eco-innovation in the tourism sector and measuring a business's ecological footprint. It introduces key concepts like ecological footprint, which measures how much biological capacity is required to support human activities. It then discusses methods for measuring ecological footprint, including using an online calculator. Finally, it outlines investment decision rules for green investments, including average rate of return, payback period, net present value, and internal rate of return as well as the time value of money concept of future and present value.