It’s one of the great scientific mystery stories of all time, and paleontologist Peter Ward tells it with great verve in this Teaching Company lecture podcast, The Search for What Killed the Dinosaurs .
Ward relates how geologist Walter Alvarez, in his quest for scientific truth and tenure, hit upon the idea that the dinosaurs, along with 75% of all species on earth, were done in by a massive meteor which collided with the Earth 65 million years ago. Ward relates the crucial help given by Alvarez’s father, Nobel prize-winning physicist Luis Alvarez.
It’s an exciting if oft-told tale, complete with spectacular quarrels and scientific backbiting. But then Ward goes on to the fascinating sequel. After mounting evidence finally convinced the scientific community that the Alvarez hypothesis was correct, a new scientific gold rush was on.
Could it be that the other mass extinctions in the fossil record were also caused by meteors? Paleontologists fanned out across the world to collect evidence, and what they found was almost as surprising as the Alvarez hypothesis itself.
What did they find? Nothing. That’s right–nothing. There was no evidence that other mass extinctions were caused by meteor collisions. Instead, it’s likely that something much more prosaic caused the other massive die-offs in the fossil record, something with an ominous resonance for our own time, namely global warming.
Of course no one is suggesting that ancient reptiles were driving SUVs or burning coal. Those earlier episodes of global warming were caused by volcanic eruptions. But all that is worth pondering as we face our own climate change conundrums.