Letters to the Editor Humans Letters from the April 28, 2007, issue of Science News By Science News April 23, 2007 at 12:51 am - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Share on Facebook (Opens in new window) Facebook Share on Reddit (Opens in new window) Reddit Share on X (Opens in new window) X Print (Opens in new window) Print Long ago gas Finding CO2 levels that are 2,500 times higher in 5,000-year-old fulgurites than in modern samples, scientists have speculated that the extra CO2 resulted from vaporization of organic material by lightning (“Stroke of Good Fortune: A wealth of data from petrified lightning,” SN: 2/17/07, p. 101).