… and neither do any other lives.
I’ve been listening to How the Earth Works, a survey course in geology from Michael E. Wysession, a professor at Washington University (St. Louis). It would surely be better as a video, but it works reasonably well in audio from Audible.
Wysession has a great knack for analogy, e.g., if the history of the Earth is your arm then you could erase human history with one swipe of an emery board over a fingernail.
What are we standing on? “The crust is literally the scum of the Earth,” says the professor, and more than 90 percent oxygen by volume.
The course dates from 2008 and therefore does not reference TIME Geophysicist of the Year Greta Thunberg. Wysession is a specialist in seismology, not in climate modeling, but he delivers the standard modeler result that the Earth is going to get warmer from the abuse it has suffered at the hands of humans, a child-like species in the professor’s view. He offers some practical tips, e.g., don’t live in the interior of a continent, especially near the Equator, because in the worst case it could be 8 degrees C hotter in 100 years. Areas near the ocean (but obviously you don’t want to buy a house right at current sea level!) will experience more moderate temperature increases.
Does he wail from his parents’ $10,000 chair like Greta T? No. He seems to take the long view. The Earth’s climate has been unusually stable for the past few hundred years. Back in the pre-Babylonian times there would be huge floods and multi-year droughts (thus leading to the stories we find in the Hebrew Bible, for example). As a geologist, he doesn’t get all that excited if the Earth gets hotter or colder for a while (“while” = tens of thousands or millions of years). What if climate change causes half of the human race to perish? Famine is the standard mechanism for controlling overpopulation of any species.
Climate is important for humans, according to the notes:
Between 0–100 C.E. warm, stable climates allowed the Roman Empire to thrive and expand. However, in 400 C.E., the climate went into an extended period of freezing. Starving Europeans migrated south and eventually overrode the Roman culture, contributing to its demise.
He also describes how the colder climate starting circa 1300 brought flood to China, which caused a boom in the rat population, which led to a boom in the flea population, which led to the Black Plague as the rats and fleas spread to the Middle East and Europe. The Plague in turn made the climate colder as “Millions of trees sprang up in now-abandoned fields, pulling carbon dioxide out of the atmosphere and cooling the climate.”
But humans aren’t important for the Earth in the long run.
For those who do want to worry about our species, Wysession brings up a lot of additional risks that don’t make it into the New York Times. When the Earth’s magnetic field “flips” from north-south to south-north, the flip happens almost instantaneously… in geologic time. There is hardly any magnetic field for 1,000 years during a “flip” and that means no magnetosphere. With no magnetosphere, cosmic rays rush in and destroy almost all of the life on our planet.
Can we predict volcanic eruptions? Not really. When a big one occurs, it can plunge us into a 1,000-year cooling period. Supposedly this happened 75,000 years ago with Toba.
What about geoengineering to stave off a big climate change? Wysession says that the sunspot cycle, which changes insolation by less than 0.1 percent, can have significant effects on the Earth’s climate (the Little Ice Age from 1550-1850, for example). So if we can build a big sunshade up in space, paint a bunch of stuff on Earth white, or fill the upper atmosphere with reflective particles we should be able to set the Earth’s temperature more or less as desired. (Failing that, plant some trees in the Sahara.)
Unlike our media and politicians, How the Earth Works covers both positive and negative feedback mechanisms for all of the cycles on our planet. Despite the discussion of human-caused climate changes, the course overall is a story in remarkable stability (not as bitingly sarcastic and funny as when told by this Nobel-winning physicist, though). Why aren’t our oceans as salty as the Dead Sea? Subduction keeps them in equilibrium by dragging ocean crust, filled with salt, down into the Earth.
Given that Americans want to talk about geoscience, but without doing any studying, watching or listening to this class could make you the life of the party (assuming that it is a very dull party). Full post, including comments