Chapter 2 reviews the mounting scientific evidence of the growing “fragility” of the Earth system and its implications for the planet. It traces the long history of how humans have exploited nature to create wealth, starting with the Agricultural Transition 10,000 years ago up to the Fossil Fuel Age and its global consequences. The chapter then focuses on the four threats created by current human impacts on the biosphere: climate change, land use and biodiversity loss, freshwater scarcity and deteriorating marine and coastal habitats. Each of these global challenges will be examined in more detail in later chapters (see Chapters 4–7).