Salt can solve mysteries, help us explore space, and reveal Earth’s past. The most fascinating is sodium’s dual role of danger and savior: It kills millions every year but also offers a cheap weapon against infections and climate change.
Morphine For A Warming Earth
In 2018, scientists at the Planetary Science Institute proposed to salt the air like a cured ham. The reason? To cool Earth down. Humans’ dependence on fossil fuels is still dialing up the planet’s temperature. The idea is to release table salt (perhaps a salt mine’s worth) into the troposphere. Its strong reflective properties might mirror incoming heat back into space.
But this is geoengineering, a practice involving environmental manipulation to stave off climate change. This remains a patchwork craft where precision understanding of all the consequences cannot be predicted.
Salt may be harmless to humans and more reflective than other suggested dustings, but it contains chlorine. This ozone nibbler could worsen the condition of Earth’s protective shield against radiation. Salt might cool Earth but could wreck the chemistry of both the troposphere and stratosphere.
Researchers admit the move is a desperate one for a situation that needs something better. They liken salt seeding to the “application of morphine in a medical situation.”
It Might Become A Controlled Substance
At the 2012 World Nutrition meeting in Rio, researchers proposed that salt be regulated by companies or governments. The population is overdosing on sodium, a leading cause of premature deaths. Not just a few thousand, either. Millions of people die of high blood pressure every year because of salt added to food.
A human needs 350 milligrams daily to stay alive. Meanwhile, an average American ingests 3,500 milligrams per day. The biggest culprit is sodium hidden from the consumer. A slice of store-bought bread already accounts for 250 milligrams of sodium. A can of vegetables contains around 1,000 milligrams. Double that in one fast-food meal.
Researchers are leaning toward taking the choice away from companies that add salt to improve taste in low-quality food and use salt water to sell meat at a “heavier” price. As salt causes thirst, beverage sellers have little incentive to support salt reduction. Faced with hidden sodium and industrial overuse, the individual cannot effectively reduce his intake. For this reason, the government regulation of salt may be the only option.
The Birth Of Oxygen
Earth was pretty much a choke zone until the first oxygen bloomed. Called the Great Oxidation Event, this change was made possible when bacteria learned photosynthesis and started releasing oxygen.
Exactly when this event happened was a mystery until 2018, when the world’s oldest salt was found. The crystallized rocks were drawn from a 2-kilometer-deep (1.2 mi) shaft in Russia.
The crystals, chemically identical to table salt, formed 2.3 billion years ago after an ancient ocean evaporated. The sample contained sulfate—something which forms in seawater when oxygen reacts with sulfur. Not only did it prove when the Oxidation Event happened, but the vast amount of sulfate showed that it spread at a rapid clip.
The massive rate at which oxygen was pumped into the atmosphere was surprising, but it settled another question. Did bacteria take millions of years to raise the 20 percent oxygen level in the atmosphere? The Russian salt showed that the process was not gradual. For some reason, the event was more like the burst from a fire hose.
Salt Causes Brain Inflammation
In 2018, researchers put mice on a high-salt diet and the results were scary. Mice are highly intelligent mammals, but the sodium dumbed them down. They performed badly in maze tests, and reactions to whisker stimulation or new objects were tepid.
Previously, salt-induced cognitive issues were believed to happen because of high blood pressure. However, the study proved that salt could mess up important parts of the brain even without blood pressure issues.
Decreased blood flow to the cortex and hippocampus impaired learning and memory. This was the end result of a crazy thing that the immune system did. When it detected too much salt in the animal’s gut, inflammatory signals were sent to the brain to compromise blood vessels and thinking.
The gut’s independent signaling is already responsible for other diseases linked to poor brain blood vessels—multiple sclerosis, rheumatoid arthritis, psoriasis, and inflammatory bowel disease. But this is the first time that salt was identified as a trigger for the dangerous inflammation.
On a positive note, the mice recovered their smarts when they were switched to a low-sodium diet or gut signals were disrupted by drugs.
Worst Droughts In History
During 2017, researchers were drilling for samples in the Dead Sea when they found something horrifying—two droughts capable of bringing civilization to its knees should they repeat. The team had been scouting for salt deposits to look at past rainfall. The logic was sound. A dry spell would leave more deposits, while rainy years thinned them.
When the drill hit the depths that represented 10,000 and 120,000 years ago, respectively, salt showed up in a big way. Found around 305 meters (1,000 ft) below the seabed, they showed droughts unlike anything recorded before. Both times, the Middle East suffered dry weather that lasted millennia. At its worst, only 20 percent of normal rainfall was seen. Humans and Neanderthals existed during the first, and by the second, Neanderthals were gone.
Scientists are worried that a rebound may make millions suffer this time, and climate predictions show the region will turn arid. The salt layers proved that the deadliest droughts happened without human interference. Now, with man-made climate change, the much-needed freshwater could disappear again.