 For the first time that we see in human history, we're starting to destabilize the very life support system that we depend upon. This is something entirely new, population, economic growth, resource use, telecommunications, transport. They are all shooting up dramatically since the middle of the 20th century. When you look at our own life support system, when you look at greenhouse gases, when you look at global temperature, when you look at the biosphere, extinction rates, they all shoot up also after the Second World War. What scientists are trying to do now is to suss out what the implications of this are and how we need to change to make sure we keep a stable planetary life support system. We call them planetary boundaries. And what we mean is we try to understand the most important few processes that define how the Earth works and try to look at the limits beyond which humans should not push them. When we do this, we find we can actually reduce the Earth to nine processes. And when we analyze the human pressure on those nine, we find that four of them are already being transgressed across the boundaries. We're into high risk danger zones. Two of the most important processes are the climate system. Many people are familiar with that. And what we call biosphere integrity, the ability of life on the planet to continue to provide the functions that support us and the ability to adapt in the future. Both of those are being eroded at a great rate. We know climate. We can see it in Australia. Increase in heat waves. More intense bushfires. More erratic rainfall system and so on. The second thing is the extinction rate we see now, and it's due entirely to human activity, is 100 to 1,000 times greater than the background natural rate of extinction species loss. This will erode our own well-being as ecosystems provide less fewer services. Water is more difficult to clean. We get more pollutants on the landscapes that aren't processed by the natural world and so on. And as this is starting to happen already, we see that it's more difficult. Humans have to spend more time and effort cleaning up what nature used to do. In some parts of the world, humans have to pollinate fruit trees because bees have gone extinct. A huge cost to humanity. Planetary boundaries are reminding us that there are limits to how much of the biosphere we can erode before it comes back to bite us. And that's what's happening now. So when experts look at that from technology, engineering, agronomy, they estimate that we can live, we can prosper with 9 billion people within the planetary boundaries. But we have to innovate, we have to change, we have to be clever. But they say we can do it.