Despite being kilometers in diameter, the two asteroids did not significantly change Earth’s climate and left few marks other than impact craters.
35.65 million years ago, two asteroids, both with several kilometers in diameterreached Earth about 25 thousand years apart. One impact formed the Popigai crater in Siberia, 100 km in diameter, while the other created the Chesapeake Bay crater in the United States, 40-85 km in diameter.
And what happened next? A giant dust cloud that blocked sunlight for centuries? Some mass extinction similar to that of dinosaurs? A catastrophe worthy of inspiring a blockbuster the Hollywood?
According to a new report published in Communications Earth & Environment, the answer is much less interesting — the research concluded that asteroids do not appear to have had effects on Earth’s climate in the long term.
Researchers have reconstructed the ancient climate by analyzing isotopes present in foraminiferal microfossilssmall shelled organisms that lived in the oceans at that time. Isotopic patterns reflect past ocean temperatures, providing information about climate conditions.
Co-author Bridget Wade explains: “Our results show that there were no climate changes significant after these impacts. While we expected changes in isotopes that would indicate temperature variations, we found nothing. This suggests that Earth’s climate stabilized quickly despite the severity of these events.”
However, the resolution of the study, based on samples spaced 11 thousand years apart, does not allow the detection of shorter disturbances, lasting decades or centuries. These disruptions could include massive tsunamisshock waves, widespread fires and temporary dust clouds in the atmosphere.
The research contrasts with results from the Chicxulub asteroid impact 66 million years ago, which caused the extinction of dinosaurs and measurable short-term climate change. Models of this event suggest climate change lasting less than 25 years, explains .
The end of Eocene Time, the period in which these impacts occurred, was also marked by three asteroid collisions smaller, pointing to increased activity in the Solar System’s asteroid belt.
The analyzed fossils revealed a slight warming of the surface oceans by about 2°C and cooling of the deep waters by approximately 1°C. 100 thousand years before the impactsbut without significant changes directly associated with the events.
The study highlights the resilience of the Earth’s climate system to these impacts and highlights the need for vigilance for potential future collisions. “This research improves our understanding of Earth’s climate history and the changing effects of asteroid impacts,” concludes co-author Natalie Cheng.
