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Now, traveling about twice as far back again in Earth time, back to 542 million years ago, we encounter another sudden massive wave of extinction instigated by runaway biology: The Cambrian substrate revolution, when the texture and chemistry of the seafloor (at that time, the entire habitable surface of the planet) was rapidly remade by a spurt of biological innovation that caused both mass death and fantastic new evolutionary opportunity...
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David Grinspoon |
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4d80f57
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celled. Then a catastrophe occurred (in the sense of sudden change), a dramatic increase in biodiversity, an anti-extinction, if you will. In a flash, there were not just some animal forms, but all of them. In the fossil record, all modern body types appear together at this moment. We don't know why this happened when it did. It's likely that the explosion had to wait until oxygen levels rose high enough to support the greater energy needs ..
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David Grinspoon |
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Yet among the multiple animal inventions at the dawn of the Cambrian were new forms of mobility. A number of critters began burrowing into these mats and braving the toxic soils beneath them. These digging, tunneling creatures are known as "bioturbators," basically life that stirs up the ground. In fact, the fossils that officially define the beginning of the Cambrian in the geological record, Trichophycus pedum, are identified by the loopi..
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David Grinspoon |
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6d71297
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Remixing Our Metaphors We're not a cancer or a disease. We are organisms doing what all organisms do, surviving and reproducing as best we can. We are, however, a kind of organism that has never existed before, and we've gotten ourselves in a situation. Fortunately, we may be equipped to get ourselves out of it. A plague does not think. A cancer does not decide to change course. A weed does not weed itself. We could.
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David Grinspoon |
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5e8ea50
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The scientific revolution has revealed us, as individuals, to be incredibly tiny and ephemeral, and our entire existence, not just as individuals but even as a species, to be brief and insubstantial against the larger temporal backdrop of cosmic evolution. If, however, we choose to identify with the biosphere, then we, Gaia, have been here for quite some time, for perhaps three billion years in a universe that seems to be about thirteen bil..
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David Grinspoon |
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society. The orbital technology enabling this observation is itself one of the strange and striking aspects of the transition now gripping Earth. If up to now the defining characteristic of Earth has been planetary-scale life, then what about these planetary-scale lights? Might this spreading, luminous net be part of a new defining characteristic? Even
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David Grinspoon |
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09124d7
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This afforded an opportunity for a close encounter with Earth as it might appear to an alien spacecraft, and Carl Sagan proposed using this as a "control experiment for the search for extraterrestrial life by modern interplanetary spacecraft." The instruments detected the spectral signature of the chlorophyll from green plants, and signs of an obviously life-altered atmosphere. As Sagan and colleagues wrote in their paper "A search for life..
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David Grinspoon |
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31e5735
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Most of the evidence uncovered by Galileo would have been discovered by a similar fly-by spacecraft as long ago as about 2 billion years. In contrast, modulated radio transmissions could not have been detected before this century. Galileo was able to detect the noisy radio chatter of the civilization that made it. Presumably any aliens studying our planet would notice the same thing, though whether this cacophony is actually attributable to..
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David Grinspoon |
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Less than eighty years later, we know all these ideas about origins (of Earth, the planets, the Moon, and mountain ranges) to be completely wrong. We're certainly not any smarter today than they were then, and almost nobody is as smart as George Gamow was. We just have better data, much of it from space exploration. As we navigate this age of extrasolar planet discovery, supercomputer climate predictions, personalized gene sequencing, and i..
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David Grinspoon |
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e95eab4
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The carbon cycle has grabbed the headlines, but we've also seized hold of many other major geochemical cycles. Through production of fertilizers, we've radically altered Earth's nitrogen cycle. The sulfur cycle has become dominated by industrial emissions. We've dammed rivers so thoroughly that there is now more than five times as much fresh water captured in reservoirs as there is remaining in all the wild rivers and streams of Earth! That..
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David Grinspoon |
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1b7e46d
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The Big Five extinctions are simply slightly more intense than the sixth- or seventh-largest declines, and you could just as easily discuss the Big Seven or Big Ten, depending on how you sliced up the data. This tally refers only to extinctions since the "Cambrian explosion," the sudden proliferation of complex animal life 542 million years ago, and it neglects extinction events that happened earlier, during several billion years of evoluti..
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David Grinspoon |
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7600627
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for the first time ever the majority of children being born today will never in their lives directly see the Milky Way galaxy. The cosmic connection has never been closer or more remote. Age
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David Grinspoon |
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6d7b432
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Using the techniques, perspective, and language of planetary exploration, Sagan, Toon, and Pollack published a paper in Science in 1979, long before climate change became the issue it is now, entitled, "Anthropogenic Albedo Changes and the Earth's Climate," in which they discussed how changing land use practices by human societies (starting with fires set by hunter-gatherers, expanding with the Agricultural Revolution, and accelerating with..
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David Grinspoon |
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6061163
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The Great Oxygenation Event was contemporaneous with one of the most severe ice ages this world has ever known, an event known to geo-nerds as the Paleoproterozoic Snowball Earth episode.* This was probably no coincidence. At the time, Earth's climate was likely being kept above freezing by a methane greenhouse. Methane is such a powerful infrared absorber that a very small amount of it can significantly warm a planet. It is also, however, ..
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David Grinspoon |
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98d3de8
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the TTAPS study and the wider debate it ignited helped drive home the absurdity of nuclear strategies dependent on massive deterrence. The United States and the USSR had created a situation where even a limited nuclear conflict would cause a climate disaster that could quite possibly, among other things, collapse global agriculture, dooming civilization as we know it. With these weapons, there was no destroying your enemy without also destr..
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David Grinspoon |
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Titan's upper atmosphere is a nonstop factory of complex organics, which both shroud this world in its permanent smoggy haze and snow down on the icy surface. There they gather in vast dune fields that blow around in the nitrogen winds and dissolve in the methane lakes. The presence of all these organics on Titan resembles our picture of the primordial Earth and the conditions that led to the origin of life. It seems to present a freeze-dri..
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David Grinspoon |
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Titan, by our standards, is really cold, at -290 degrees Fahrenheit. Without any methane greenhouse, it would be much colder still, by about 22 degrees. Yet, if we put all that methane into a basic climate model, we find that there should be about twice the level of greenhouse warming that is actually observed. What's missing from the model? This question led to the discovery of the "anti-greenhouse effect."5 It has to do with all that oran..
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David Grinspoon |
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f72f9b4
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When a reporter asked Gandhi what he thought of Western civilization, he replied, "I think it would be a wonderful idea." I would say the same about human intelligence. If we are not intelligent, then what is? Here's my crack at a definition: A truly intelligent species must have the ability to behave, collectively, in ways that ensure long-term survival. It must have learned to avoid self-destruction, anticipate and avoid natural disasters..
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David Grinspoon |
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this way, we've changed the geometry of the planet. Before we came along, the world was discontinuous. Oceans, deserts, and mountain ranges formed impenetrable barriers, breaking Earth into separate regions where populations could evolve independently, and then be isolated or merged by continental drift and climate change. Now we've created pathways around all those borders, and to some degree the planet is one continuous habitat. Some
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David Grinspoon |
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Historian Charles Mann has suggested that this mashed-up new biological phase we've induced be called the Homogenocene, as we have blended so many evolving populations, once geographically dispersed and isolated, into one homogenized genetic broth. In the 1970s Carl Sagan used to zip around Ithaca, New York, with a bumper sticker on his orange Porsche reading, "Reunite Gondwanaland!" referring to the time when all Earth's continents were me..
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David Grinspoon |
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We are already behaving differently from that bacterial colony in a petri dish, deviating from the fatal S-curve, using our limited but growing global cognitive capacities to anticipate and soften or avoid the crash. We are waking up, and we can see the trends starting to turn. We are slowly rounding the corner on the related problems of poverty and overpopulation. The Bill and Melinda Gates Foundation,
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David Grinspoon |
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b4a1db0
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cities will be smarter, greener places. Over the centuries, we've made a lot of progress in learning how to urbanize. We invented plumbing and sanitation systems, learned not to stain our cities brown with coal ash, realized we don't want polluted urban rivers. We are still learning how to live well in cities. I bet twenty-second-century cities will be nice places to live. Our
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David Grinspoon |
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c731795
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In 1929, as a young man, British biologist J. D. Bernal wrote a book entitled "The World, The Flesh and the Devil" that Arthur C. Clarke called, "the most brilliant attempt at scientific prediction ever made."
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David Grinspoon |