A new study published in Science Advances suggests that the near-Earth asteroid Bennu poses a significant threat to global climate stability. With a 1 in 2,700 chance of impacting Earth in September 2182, astronomers estimate that Bennu could cause substantial damage if it were to collide with our planet.
Bennu is estimated to be around 500 meters in diameter and contains the building blocks of life. It’s a medium-size asteroid that collides with Earth about every 100,000 to 200,000 years. Researchers modeled the effects of such a collision on global climate patterns, oceans, and ecosystems across land.
The study found that a Bennu-type collision could lead to a “global winter” with reduced rainfall, cooling temperatures, and disruptions in food security. The impact would generate powerful shock waves, earthquakes, and massive tsunamis if it were to strike the ocean. This event could cause prolonged ozone depletion, global warming, or even an “impact winter,” characterized by cold temperatures, reduced sunlight, and decreased precipitation.
The researchers used climate models and supercomputing power to run different scenarios for a Bennu-type collision. The results showed that dust particles injected into the atmosphere could persist for up to 4 years after the impact, leading to dramatic disruptions in atmospheric chemistry and climate.
However, not all effects are negative. Marine plankton responded unexpectedly well to the iron-rich conditions created by the asteroid’s debris. This led to unprecedented blooms of algae, particularly diatoms, which could potentially alleviate food insecurity related to reduced terrestrial productivity.
The study highlights that even relatively small impacts can have severe effects on ecosystems and climate stability. Researchers emphasize that it’s essential to study such events to better understand their consequences and prepare for potential threats.
Source: https://edition.cnn.com/2025/02/05/science/bennu-earth-impact-scenario/index.html