Chapter 1: The Younger Dryas Event

Recent discoveries indicate that a collision between Earth and a high-speed asteroid may have triggered a colossal global inferno, resulting in widespread extinction nearly 13,000 years ago. Christopher Moore, the lead researcher, discusses these findings with The Cosmic Companion.

During this period, known as the Younger Dryas (YD), the planet experienced a severe cold spell that led to the extinction of numerous species, including the woolly mammoth, saber-toothed cat, giant sloth, and mastodon. Human populations, including the Clovis culture, also faced drastic declines during this time.

The woolly mammoth was just one of the many species that faced extinction during the Younger Dryas.

Following the impact, extensive wildfires may have obscured sunlight over large parts of the Earth, leading to a significant drop in temperatures and the subsequent extinction of many plant and animal species. At the height of these fires, an estimated 10% of the Earth's land, roughly 10 million square kilometers, burned.

Since 2007, scientists have theorized that an extraterrestrial impact may have shifted Earth's climate, culminating in this mass extinction event. This theory is referred to as the Younger Dryas Impact Hypothesis.

Section 1.1: Discovering Evidence

Archaeologist Christopher Moore from the University of South Carolina spearheaded a study at White Pond in South Carolina, where sediment samples were collected to reveal geological conditions from the onset of the Younger Dryas extinction. The sediment cores uncovered a 10 cm (four inch) wide layer, dating back to the period between 12,835 and 12,735 years ago.

Christopher Moore analyzing sediment cores. Image credit: Christopher R. Moore, CC BY-ND

At this site, traces of platinum—potentially remnants from an asteroid—were discovered alongside high levels of soot, indicating a massive wildfire at the start of the Younger Dryas. Additionally, concentrations of fungal spores, indicative of large herbivores, were notably scarce, suggesting a significant decline in ice-age megafauna around 12,800 years ago.

Platinum deposits from this era have been identified across various global locations, including North America, western Asia, Europe, South Africa, and Chile. While platinum is uncommon on Earth, it is found in greater abundance in asteroids.

Traditionally, it was believed that the Younger Dryas Impact Hypothesis mainly affected the northern hemisphere, leaving the southern hemisphere relatively unscathed. However, recent discoveries of platinum deposits in Chile and South Africa indicate that the impact's influence extended to regions south of the equator.

In the newly identified Hiawatha Crater in Greenland, researchers analyzed ice cores and found elevated levels of platinum and iridium—elements that are rare on Earth but prevalent in asteroids. This discovery could serve as critical evidence supporting the notion that this crater is a remnant of the impactful event that triggered global extinction.

Collecting sediment cores from White Pond in 2016. Christopher R. Moore, CC BY-ND

The evidence further suggests that rather than a singular impact, the event may have involved multiple airbursts and collisions worldwide. Following this cosmic event, Earth, which had been experiencing warming trends since the last ice age, was plunged back into a cooler, darker climate. This period of colder temperatures lasted nearly 1,400 years until a sudden warming occurred.

“The conclusion of the Younger Dryas, around 11,500 years ago, was particularly rapid. In Greenland, temperatures surged by 10°C (18°F) within a decade,” according to the National Centers for Environmental Information.

Our ancestors may have witnessed immense wildfires like this one, as 10% of the Earth ignited approximately 12,800 years ago. Image credit: University of Kansas.

If such an impact were to occur today, temperatures in the northern hemisphere could plummet by as much as eight degrees Celsius (14 degrees Fahrenheit)—the equivalent of changing from Miami, Florida, to Montreal, Canada. Moore warns that the repercussions for modern society could be catastrophic.

“A similar incident today could lead to severe disruptions for modern civilization. Depending on the impact's location, it could trigger wildfires, a temporary winter (lasting weeks to months), as well as oceanographic and climatic shifts reminiscent of those during the Younger Dryas,” Moore explains for The Cosmic Companion.

Chapter 2: Ongoing Research and Future Implications

This video titled "The Science Behind Asteroid Impacts | Fire In The Sky" delves into the mechanisms and effects of asteroid impacts, shedding light on their historical significance.

Research into the potential impacts of the Younger Dryas remains ongoing, with many questions yet to be answered. The exact nature of the impactor, including its size and composition, is still uncertain.

“If we can accurately date the Hiawatha Crater to the Younger Dryas, it will provide us with clearer insights regarding the size and mass of the impactor, although there are likely more impacts as well as airbursts that occurred,” Moore clarifies.

Shortly after the identification of the Hiawatha impact crater beneath the ice of northwest Greenland, another similar formation was discovered just 114 miles away.

The second video, "How Ancient Humans Survived Near Extinction and a Comet Impact," explores how early humans navigated the challenges posed by cosmic events, providing context for survival during catastrophic changes.

The reasons behind the decline of the Clovis people and the extinction of various ancient species nearly 13,000 years ago remain elusive. However, Moore and his team believe that their findings supporting the Younger Dryas Impact Hypothesis will eventually gain wider acceptance among researchers and the public.

Some scientists, however, still advocate the idea that the melting of ice dams in North America's freshwater lakes released large amounts of freshwater into the North Atlantic, disrupting ocean circulation and cooling the climate.

“Such debates have persisted for an extended period. Ideas in science often take a long time to achieve broad acceptance—similar to the initial resistance faced by the asteroid impact theory regarding dinosaur extinction and the concept of plate tectonics. Now, these ideas are well-established,” Moore remarks in a press release from the University of South Carolina.

“The dinosaurs became extinct because they didn’t have a space program.”

— Larry Niven

Much like the impact that concluded the reign of the dinosaurs, the asteroid responsible for the Younger Dryas extinction likely left a global trace in the form of rare metals. However, calculations suggest that this event was triggered by a significantly smaller body compared to that which led to the extinction of the dinosaurs and many other species over 65 million years ago.

Dryas octopetala, a wildflower that thrived in Europe during the Younger Dryas period. Image credit: NOAA.

“The energy from the YD impact was of a smaller magnitude but still significant, likely dispersed globally through a combination of impacts and airbursts from a fragmented comet or asteroid,” Moore explains.

The Younger Dryas period is named after Dryas octopetala, a wildflower that flourished across Europe during the cold snap. This research was published in the journal Scientific Reports, a publication of Nature.

Did you enjoy this article? Consider subscribing to The Cosmic Companion Newsletter!