Deccan Traps Erupt

• before the impact

• flood basalts in modern-day India

  • up to 600,000 miles covered in lava

• acid rain (SO2), ozone depletion, global cooling (SO2), global warming (CO2), etc.

Pangaea Breaking Up

• many species already going extinct due to the breakup of the supercontinent

• continents move apart → sea level rises

Conclusion

• the Cretaceous biosphere was already stressed

• the impact was the final nail in the coffin

  • this was also probably the causal factor in the extinction of the dinosaurs

Did the Dinosaurs Really Go Extinct?

• biologically, birds are descendants of dinosaurs

  • example: the Cassowary bird the is bird that most closely resembles a dinosaur in today’s age

  • crocodiles and alligators are also thought to be descendants of the dinosaurs

• the K/Pg extinction caused extinction of “non-avian” dinosaurs

How Concerned Should We Be?

• there doesn’t have to be a “mass extinction” event to be bad

• civilization killer → this is random and would probably only occur 1 in 1 million years

• we might kill our civilization on our own

  • current extinction rate is 1000 times higher than the background rate

  • if all threatened species become extinct by 2100, we would be in a mass extinction event

    • within 240-540 years, magnitude would be comparable to past mass extinctions