Britannica
Sources used in this answer
How did the Chicxulub impact affect life on Earth?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
geologic history of Earth
Discover how old Earth is and discover the timing of important events in Earth's history in our interactive.
The Chicxulub impact, which occurred approximately 66 million years ago, triggered a mass extinction event that eliminated roughly 80 percent of all species on Earth, marking the end of the Cretaceous Period.12
The collision of an asteroid 10–15 km in diameter caused catastrophic environmental changes:12
- Atmospheric Disruption: The impact ejected massive quantities of debris and sulfur into the atmosphere, creating a global dust cloud that blocked sunlight for years or even decades. This halted photosynthesis, collapsing the food chain and causing global temperatures to plummet by as much as 28 °C.32
- Oceanic Impact: The release of sulfur led to acid rain, which acidified the oceans and devastated marine life, including plankton, ammonites, and various marine reptiles.32
- Immediate Destruction: The event triggered widespread wildfires and a massive tsunami that caused significant regional damage.32
While dinosaurs and many marine groups perished, other organisms—including birds, small mammals, and insects—survived, eventually leading to a period of adaptive radiation in the Cenozoic Era.24