words by willow defebaugh
Welcome to The Overview, a weekly newsletter in which Editor-in-Chief Willow Defebaugh offers an aerial view of the latest events in climate and culture—and how they all fit together.
“It is always what I have already said: always the wish that you may find patience enough in yourself to endure, and simplicity enough to believe; that you may acquire more and more confidence in that which is difficult, and in your solitude among others. And for the rest, let life happen to you. Believe me: life is right, in any case.”
In May of 1891, T.L. Phipson wrote an article for the Scientific American about his inquiry into a phenomenon that, at the time, had no name: the pleasant scent that often appears after rainfall. Perhaps you have observed this olfactory sensation—which is altogether impossible to describe—stepping outside after a spring shower, the sweet smell of newness in the air.
Seventy-three years after Phipson’s query, Australian mineralogists Isabel Bear and Richard Thomas described the process through a new scientific lens in the journal Nature, explaining that the odor arises from an oil produced by dry plants in combination with a compound called geosmin, the byproduct of a bacteria named Streptomyces found in healthy soil. When raindrops hit the Earth, the aroma is released into the air. They named the scent petrichor.
Perhaps the most interesting aspect of petrichor is that humans are exceptionally equipped to perceive it. As perfumer Marina Barcenilla put it, “There’s something very primitive and very primal about the smell…Even when you dilute it down to the parts per billion range, [humans] can still detect it.” Primal is an apt word, since some scientists suspect we have our ancestors to thank for it—that our affection for the smell is inherited from those who relied on rainfall.
Another odor associated with storms that humans have relied on throughout time serves as more of an omen, often whiffed before the weather turns as opposed to after it has passed. More metallic than sweet, it is derived from ozone, a molecule that forms when oxygen interacts with electricity—in this case, lightning. The scent often blows in from afar, a warning from nature as to what’s approaching on the horizon.
While petrichor can be observed all over the world, nowhere is it as apparent as it is in extreme climates, such as dry desert areas that experience epic seasonal storms and monsoons. In their research, Bear and Thomas found that the scent is somewhat of a signature to the village of Kannauj in Uttar Pradesh, India, where it is captured and sold as a fragrance—a practice that continues to this day. There, the aroma is known as mitti attar, the Earth’s perfume.
When I decided to research petrichor for this week’s newsletter, I had no idea that I would be writing it next to an open window, smelling the aftermath of our first spring rain (it is perhaps less potent in Brooklyn where bare soil is scarce, but I’m grateful all the same). Rather, I was pondering patience and the wonder that awaits us on the other side of every rainfall when we are willing to see it through.
The word petrichor itself is a combination of the Greek petra (meaning rock) and ichor, a reference to the mythological substance said to flow in the veins of ancient gods and goddesses. Perhaps it is a testament to our own olympian endurance and all we have been through—the many storms we weather in our lives, the sweet scent of relief and the wisdom we are left with in their wake when we realize the worst is behind us. After all, isn’t that divine?
