The article written by Lisa M. Krieger elaborates relating to lesson from california's ancient drought. Most of modern Californians facing frightening question toward the recent dry spell in California. Is the drought caused by an aberration or it could be a signal of mega drought that occurred several decades ago. Scientists have tendency to keep of the related question. According to several evidence that is measured in centuries, however, scientists agree that California is more vulnerable to drought. The most valid evidence is tree rings. The varying widths of the trees represent that a wide range of prejudicial dry spells gripped the west in the late 1500s. Other predominant study lead by Edward Schulman using tree rings in the 1940s found sustained period of low flow in Colorado river. Some scientist believe that megadrought returned in 21 century. Bill Patzert has identified the temperature of Pacific Ocean that contrive a ridge of high pressure over California to Alaska and freezing cold to the eastern United States. As a result, this phenomenon has significant ramifications such as more wildfires, wells go dry, field would go fallow, less water for agriculture, cities and wildlife.