The climate chaos was now full-tilt climate anarchy. “The Deccan Traps are still erupting after that event,” says Yale University geochronologist Jennifer Kasbohm, who studies volcanoes’ influence on climate change but wasn’t involved in the new paper. “It was a really bad day, but things continue to be kind of rough on planet Earth for a few hundred thousand years more. And then maybe you’re getting back to normal, although missing some of your old friends, in terms of species that used to be around.”
The asteroid’s impact released so much energy, in fact, that it may have triggered more volcanic activity at the Deccan Traps. The shock could have essentially jostled the plumbing in the volcanoes, driving magma to the surface. “There would be a huge amount of energy being propagated around the world,” says Renne. “When you perturb that system violently, you can actually do several things, one of which is you induce gases to be released from the liquid. I hate to use such a simplistic analog, but it’s like shaking a can of soda. That triggers eruptions.”
However, not everyone in the scientific community is Team Volcano. “There are people who have argued—and continue to argue—very, very fiercely about this,” says Peter Roopnarine, curator of geology at the California Academy of Sciences, who wasn’t involved in the research. “I would say that the asteroid definitely played a major, if not the major, role. Really, the question is, to what extent did the volcanism also play a role?” There are still many uncertainties, Roopnarine says, such as the timing of the volcanic gas release over those hundreds of thousands of years.
An asteroid also causes a distinctly different kind of climate trauma than a slow gas leak. “In the opinion of many of us, the major kill mechanism—if you will—from the impact would have been darkness, not cooling,” says Roopnarine. “You would have enough material injected into the atmosphere that it would have blotted out the sun up to, let’s say, 10 years or so.”
All of this has added a great deal of subtlety to the asteroid vs. volcanoes debate. This new modeling tries to set human biases aside and let machines do the number crunching. So far, the answer seems to be that both natural disasters played a role, in a kind of one-two punch. “To many people who aren’t really following the field that closely, it seems like, ‘What are you guys doing? You’re flailing around. Get to the answer, goddammit,’” says Renne. “Twenty years ago, people would stop at ‘Well, was it an asteroid or was it the volcanism?’ And that was as far as the argument went. Now, people are much more concerned about the nuances.”