Earth has been lucky for a long stretch of history, avoiding direct impact from a major asteroid. However, space remains unpredictable, with countless celestial bodies hurtling through the cosmos. Among them is asteroid Bennu, which has a slim, yet nonzero, chance of colliding with Earth in the distant future.
According to climate simulations conducted by researchers in South Korea, a hypothetical impact by Bennu in September 2182 could unleash devastating environmental consequences. Despite its relatively modest size—measuring around 500 meters (1,640 feet)—compared to the Chicxulub impactor that wiped out the dinosaurs, the potential fallout is deeply concerning.
As scientists Lan Dai and Axel Timmerman from Pusan National University warn, “Our simulations, which inject up to 400 million tons of dust into the stratosphere, show marked disruptions in climate, atmospheric chemistry, and global photosynthesis.”
Their findings, obtained using the Aleph supercomputer, reveal that the aftermath of such a collision would be far worse than the initial impact itself. A dust-filled sky would plunge global temperatures by 4 degrees Celsius, while precipitation levels would drop by 15 percent. In addition, atmospheric ozone depletion could reach a staggering 32 percent, making life on Earth increasingly vulnerable to harmful radiation.
“The abrupt impact of winter would provide unfavorable climate conditions for plants to grow, leading to an initial 20 to 30 percent reduction of photosynthesis in terrestrial and marine ecosystems,” Dai explains.
With agriculture and natural food chains severely disrupted, global food security could face an unprecedented crisis.
Yet, not all ecosystems would collapse. Algae, particularly marine diatoms, showed a surprising ability to rebound quickly, thriving on the iron-rich dust released by the impact. This unexpected response could provide a critical food source for marine life, potentially easing the burden of food shortages.
While large asteroid impacts remain unpredictable and infrequent—estimated to occur every 100,000 to 200,000 years—scientists believe they may have played a role in shaping human evolution. As Timmerman puts it, “This means that our early human ancestors may have experienced some of these planet-shifting events before with potential impacts on human evolution and even our genetic makeup.”
Despite the grim outlook, history suggests that humanity is nothing if not resilient. As the study implies, even in the face of catastrophic asteroid impacts, we may not just survive—but adapt, as we always have. Or, as the researchers wryly suggest, perhaps we’re as stubbornly persistent as cockroaches.
