19.2 and 22.7 miles wide... I can’t even begin to imagine what damage those two meteorites would do to whatever was living on earth, way back then.
Considering the Chicxulub (suspected dinosaur killer 65mya) impact was by a body somewhere between 7 and 50 KM diameter, and said impactor’s crater is over 150 kilometres (93 miles) in diameter...
I doubt that it was more than a couple of bad years weather for the rest of the planet. For those in the immediate area, however, it was likely pretty ugly for a long while!
It's nothing compared to the Existential Threat of man-made global warming:
Amy Klobuchar Declares That Global Warming is An "Existential Threat"
World Bank ups funds to tackle 'existential threat' of climate change ($200B!)