Scientific American: Dear EarthTalk: Could it really be true that we are in the midst of the worst drought in the United States since the 1930s?Deborah Lynn, Needham, Mass. Indeed we are embroiled in what many consider the worst drought in the U.S. since the Dust Bowl days of the 1930s that rendered some 50 million acres of farmland barely usable. Back then, drought conditions combined with poor soil management practices to force some 2.5 million Americans away from the Great Plains, only wreaking further havoc on...