Mammoth-killing comet question

This article is not about an asteroid wiping out the dinosaurs.  It is about a much more recent cosmic event, an hypothesis that about 13,000 years ago a comet killed the woolly mammoths as well as the prehistoric humans known as the Clovis culture.  One feature of that hypothesis is that a cometary impact over North America ignited fires across the whole continent.  Unfortunately, analysis of charcoal and pollen records from the time of the hypothesized impact doesn’t support the theory.  The research reported here and published in the Proceedings of the National Academy of Sciences doesn’t show any sign of continent-wide wildfires on a scale that could exterminate entire species and cultures; it does indicate that the greatest incidence of fires occurred just after periods of sharp climate change.  Not surprisingly, the proponent of the cometary impact theory and the current researchers disagree over how to interpret the latest findings.  Climate watchers, however, place more importance on the fact that the research provides the first hard evidence that more fires than normal occur after periods of climate warming.  This suggests that areas of low fire occurrence, like Britain, aren’t prepared for increases in wildfires due to climate warming, which can have impacts other than just rising sea levels