Thanks for inviting me here today. I'm going to talk about environmental indicators, which are ways we measure impacts on the environment. I'll mention two of the most important ones. I'll start with the term 'carbon footprint', which some of you may know. Carbon footprint refers to the annual amount of greenhouse gas emissions that result from the activities of an individual or a group of people. It looks especially at the use of energy, transport and the consumption of goods and services, and is usually measured as the mass of carbon dioxide, or CO2 emissions. We can also calculate the carbon footprint for an event, such as a music festival, and for products, such as a computer. The other important and commonly used indicator I'll mention today is called the 'ecological footprint'; the term refers to a population's environmental impact based on the area of land and sea needed to sustain its lifestyle. The measure takes into consideration the amount of food needed as well as the number of trees required to absorb the population's CO2 emissions. It's interesting to note that if everyone in the world had the ecological footprint of an average person in a developed country, then the resources of three planet Earths would be needed to support them.