We have 600 million years of information about the climate at CO2 levels up to 6,000 ppm. For example, there was an ice age during the Ordovician with CO2 levels 20X higher than they are today. Huge coral reefs formed during the late Permian with CO2 levels 10X higher than today. There is no indication in the historical record that higher CO2 levels kill coral reefs or are associated with monster hurricanes.
Many climate scientists aren’t interested in empirical data, choosing instead to use climate models which can be tuned to generate the results they want to see.