Global research program Deep Carbon Observatory (DCO) found that human-made CO2 emissions are 100-times greater than volcanoes. The research team estimated that the 'Chicxulub' impact 66 million years ago, which is believed to have killed off 75% of all life on Earth, released between 425 and 1,400 gigatonnes of CO2. Human-made emissions in 2018 alone topped 37 gigatonnes.