The reason why we did this study was that years ago there was some concern about how much of the planet's net primary production people were demanding on an annual basis. In other words, can the Earth keep up? If you look at the planet, the land surface produces a certain amount of vegetation based on all the agricultural inputs we have now, our natural climate ecosystems - that's an amount that sort of constitutes the total available amount of biomass that's present for consumption. And the human appropriation component as we've measured it is actually how much NPP, or plant growth, is required to generate the products that are being consumed annually by people all over the world in terms of food, fiber, building materials, and also fuel for charcoal and wood-based fuels. We used satellite data over a long period of time to estimate how much plant material the land surface generates and then compared that against the amount plant material that humans need in terms of food, fiber, and fabrication, and we found that two things are happening. We are increasing our per-capita consumption, so as individuals we are increasing how much we consume on an annual basis, and we're also increasing our population, so both of those factors have come together to move us from about 20 percent of the actual global supply to consuming 25 percent. And so what we're concerned about is that in the future world where we've increased both populations and consumption that we'll hit some tipping point where the ecosystems where they are now and the current climate that we have will not be able to produce the products that we need to keep the lifestyle that we have now. If that future trend continues, we're going to be pushing 55 percent of the capability of the land surface by 2050. If you bring into that now the conversion of land to produce fuels to replace fossil fuels then the pressure even becomes more severe. So, what we're finding is that the biosphere doesn't really care if you have a few people consuming a lot, or a lot of people consuming a little, it's the total amount in the end that actually matters. And so, we as a species we have two issues, we have our per capita consumption to think about, and our overall numbers. The implications of such high demand come about in various ways. One is that we are vulnerable to climate change and that we have to very carefully manage our ecosystems so that they keep producing the products that we require. Also we have to worry about the loss of biodiversity from the natural ecosystems because there will be fewer of those left as we have to convert more and more land to uses that produce the products that we use on a daily basis. [satellite: beep-beep, beep-beep, beep-beep]