The high northern and southern latitudes were indeed coated in soot and were left to freeze over time, which means that many land creatures, including the dinosaurs, died out here. However, they state that the lower, near-equatorial latitudes would have not been smothered in nearly as much soot, which means that they would have experienced milder cooling and droughts. This would have been enough to kill off the non-avian dinosaurs, but other creatures, including the crocodilians, would have survived.
In fact, 1.5 billion tonnes (1.65 billion tons) of soot was likely to have been ejected into the atmosphere, according to their modeling – enough to cause one of the worst mass extinctions in Earth’s 4.54 billion years of history.
The dinosaurs were pretty screwed by the time the antagonizing asteroid ploughed into Earth 66 million years ago. Prolonged volcanism, the rise of mammals, and rapid climate change had sent them into a spiral of decline, but when that fateful impact crater, 180 kilometers (110 miles) across and 20 kilometers (12 miles) deep was formed, the resulting global apocalypse finished them off.
Wiping out up to 75 percent of all life on Earth, land creatures were affected most severely at first, but marine life also suffered greatly soon after. The authors note that the interruption of photosynthesis in the upper water column would have killed off a major food source for larger forms of marine life, and previous studies showed that those that survived only did so thanks to a trickle-down stream of algae.
The Yucatán Peninsula, the impact site for the asteroid 66 million years ago, as seen from the International Space Station. Tim Peake/ESA/NASA