Research in China shows that previous global warming was NOT simply due to an asteroid hitting the earth. If you're an adherent of intelligent design you can suppose that some god decided to wipe out half of creation and to use volcanic dust to do it. Sounds perfectly intelligent to me.
For the rest of us, science indicates that massive extinctions occurred on Earth about 250-million years ago. That was at the end of the Permian and was apparently caused by asteroid slamming into the earth, striking somewhere that's now buried beneath an ocean. That's what previous research indicated. The research in China now confirms some of what's been read from the geological record in Iran and Austria. One change: the Chinese data shows there were two successive warming events, both likely caused by volcanoes. One came before the accepted date of the asteroid collision. The extinctions of many species was accompanied by a global bloom of blue-green algae. I thought we were going ot make biodiesel out of that stuff?So we don't need those old-fashioned volcanoes for a major wave of extinctions, we're now doing our own dirty work with current technology and increasing greenhouse gas emissions. Seems the intelligent design we need now must come from all-too-human eningeers and corporations, from consumer choices and global political efforts. If those fail, what species will be reading the rocks in 250-million years trying to figure out what happened to those clever hominids?