Privileged Planet: a brief summary of why it is (Introduction)

by David Turell , Wednesday, October 23, 2019, 21:58 (1646 days ago) @ David Turell

I'll present the bits and pieces which need no explanation, but the odds deny chance:

https://blogs.scientificamerican.com/observations/a-science-based-origin-story-for-a-pl...

"During my lifetime—since the mid-20th century—we humans have suddenly become so powerful that what we do in the next 50 years will shape the future of all the species with which we share this planet. Whether we realize it or not, we have become the custodians of planet Earth.

"Those who are young today will have to learn how to grow into the new role of planetary custodians. But how do you do that? No species has ever played this role in the four billion years since life first appeared on our Earth (though groups of species, such as the first oxygen-producing organisms have transformed the biosphere).

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"Those who are young today will have to learn how to grow into the new role of planetary custodians. But how do you do that? No species has ever played this role in the four billion years since life first appeared on our Earth (though groups of species, such as the first oxygen-producing organisms have transformed the biosphere).

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"For millions of years the Earth was covered with ice during several so-called “snowball Earth” episodes. But volcanoes came to the rescue each time, by pumping up new supplies of greenhouse gases beneath ice sheets that covered the planet. And eventually, new oxygen-breathing organisms evolved and proliferated, creating a new atmospheric balance. Taken together, these mechanisms, and perhaps others that we do not yet understand, kept the Earth’s surface temperatures within the Goldilocks range for life, even as heat from the sun kept increasing.

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"Within the protected temperature-controlled cocoon of the young Earth, life flourished and evolved, creating a huge variety of homes for living organisms in the planet’s oceans and seas. As oxygen levels increased with the spread of photosynthesizing plants, oxygen’s fierce chemical energy drove more extravagant and exotic forms of evolution. Multicellular life forms really began to flourish only in the last 600 million years, and only in the last 400 million years did large organisms begin to colonize the Earth’s continents, eventually greening large parts of their once rust-coloured landscapes, and filling the new jungles and savannas with the roars and screams of vast new creatures such as the dinosaurs.

"We humans are very much part of this story. Like all our mammalian relatives today, we flourished because of a cosmic accident that struck down most of the large reptiles that dominated the continents 65 million years ago.

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"Humans evolved as part of this trend to larger brains. Relative to our body size, our brains are spectacularly big. But what really makes us humans different is some piece of rewiring in our brains that we don’t fully understand, which opened up entirely new forms of communication. We are different because we can tell each other stories, pass on new information, share jokes and even explain what we are feeling and imagining.

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"We share so much information with such precision that information can accumulate, community by community, across many generations. We are the first species in four billion years that can accumulate information over many generations, through what we can call “collective learning.”

"And information, of course, is power. More information means a greater ability to manage our environments, to hunt or gather food, and to manipulate our surroundings. Over some 200,000 years, at a rate that was barely perceptible at first but has gradually accelerated, we learned more and more powerful ways of managing, exploiting and eventually transforming the landscapes, plants and animals around us. We share so much information with such precision that information can accumulate, community by community, across many generations. We are the first species in four billion years that can accumulate information over many generations, through what we can call “collective learning.” Today, this increasing ecological power explains why we are so populous, why we dominate all terrestrial environments and why, since discovering how to tap the colossal energy locked inside fossil fuels, we have begun to transform the Earth’s surface, its oceans, its atmosphere and the other species that share the planet with us."

Comment: The entire article shows all the seemingly chance events that led to the appearance of humans. These contingent events, carefully building upon one another carefully protected the evolving Earth to mature and protect the appearance of humans by removing any extreme events that might have killed the process.