From the CO2Science.org archive: If you want to learn about the Joshua Tree qua tree, either google its Latin name Yucca brevifolia or be sure to avoid adding “the” in front, otherwise you’ll get pages full of hits about the 1987 U2 album. The Joshua Tree is native to the US Southwest and according to legend was named by Mormon settlers who apparently thought it reminded them of Joshua of the Bible. Since you ask, either it looked like him praying during the conquest of Ai, though no photographic record exists of his posture at that juncture, or it was leading them to the promised land out of a desert. Or it had a shaggy beard. Or someone made the whole thing up long afterward. Plant names are wacky, as we’ve mentioned. But whoever’s likeness it does not enjoy, it also does not enjoy a very expansive habitat and while its numbers are holding up it is threatened by wildfires and invasive grasses. Though of course Wikipedia blames climate change. No word on whether Wikipedia will credit CO2 for its future prospects but in 1998 there was one experiment that showed an additional 300 ppm CO2 boosted Joshua Tree growth by 65 percent. So it still hasn’t found what it’s looking for, namely a land flowing with CO2.