LITMIR.BIZ

      ADVENTURES IN THE ANTHROPOCENE

INTRODUCTION: THE HUMAN PLANET

       Four and a half billion years ago, out of the dirty halo of cosmic dust left over from the creation of our sun, a spinning clump of minerals coalesced. Earth was born, the third rock from the sun. Soon after, a big rock crashed into our planet, shaving a huge chunk off, forming the moon and knocking our world on to a tilted axis. The tilt gave us seasons and currents and the moon brought ocean tides. These helped provide the conditions for life, which first emerged some 4 billion years ago. Over the next 3.5 billion years, the planet swung in and out of extreme glaciations. When the last of these ended, there was an explosion of complex multicellular life forms.

       The rest is history, tattooed into the planet’s skin in three-dimensional fossil portraits of fantastical creatures, such as long-necked dinosaurs and lizard birds, huge insects and alien fish. The emergence of life on Earth fundamentally changed the physics of the planet.1 Plants sped up the slow breakdown of rocks with their roots, helping erode channels down which rainfall coursed, creating rivers. Photosynthesis transformed the chemistry of the atmosphere and oceans, imbued the Earth system with chemical energy, and altered the global climate. Animals ate the plants, modifying again the Earth’s chemistry.

       In return, the physical planet dictated the biology of Earth. Life evolves in response to geological, physical and chemical conditions. In the past 500 million years, there have been five mass extinctions triggered by supervolcanic eruptions, asteroid impacts and other enormous planetary events that dramatically altered the climate.2 After each of these, the survivors regrouped, proliferated and evolved. The diversity of plants, animals, fungi, bacteria and other life on Earth is richer now than at any point in time.3

       And us? Anatomically modern humans didn’t arrive until nearly 200,000 years ago and it was touch and go whether we would survive. But something pulled us through, the something that differentiated us from the other species in this shared biosphere and made us so successful that we now rule our world: the human brain. We’re more intelligent and use tools better than the other animals. And humans can make and control fire. Ever since the first human lit the first spark, our destiny as the most powerful species was assured. Having this external source of energy, which we could move wherever we chose, gave us power over the landscape, protection from other animals, allowed us to cook our food, keep warm and, ultimately, take over the world.

       For thousands of years, humans shared the planet with Neanderthals and our other cousin species. A supervolcanic eruption at Toba in Indonesia 74,000 years ago nearly wiped us all out – the human population shrank

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