From the development of our remarkable brains to the geographic divides in the way we vote, our shape-shifting planet has guided the path of humanity

Earth 16 April 2019
figure in sea

Picfair/Jed Pearson

HUMANITY today is actively reshaping the planet. Our appetite for natural resources and large-scale industrial activity is eradicating species, warming the oceans and disrupting the global climate on an unprecedented scale. So profound is our impact that some have called for the times we live in to be declared a new geological period: the Anthropocene, the age of humanity.

But this ability to shape our environment on such a scale is a recent phenomenon. For most of our history, it is our environment that has shaped us. The physical features of the planet we live on enabled our species to arise, nurtured our remarkable brains, facilitated our spread across the planet and even encouraged the birth of the first cities. This is the remarkable story of the way Earth has moulded humanity, and how we have turned the tables to shape the world.

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How we emerged

Some 55.5 million years ago, Earth’s thermostat did something unexpected. In the space of 100,000 years, barely the blink of an eye on geological timescales, the temperature of the planet jerked up by between 5°C and 8°C, hovered for a bit, and then came back down. This brief planetary fever was hugely disruptive to life on Earth, driving the rapid evolution and divergence of whole new orders of animals, including our own.

The principal culprit is thought to have been methane. As a powerful greenhouse gas, its presence in air makes our atmosphere trap more of the sun’s heat than it usually would, raising the temperature …

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View Article Here New Scientist – Earth