Image: A tunnel boring machine breaks through rock after a five-year-long dig through the San Bernadino Mountains in southern California August 20, 2008.
CALIFORNIA is facing one of the worst droughts in its history. "We're potentially headed to one of the worst droughts we've ever had in California because of the conditions of storage, the fact that we're expecting very erratic weather patterns, and we have much more demand than the last drought in 1993." A massive mechanical mole surfaced on Wednesday from a nearly 5-year journey under mountains in the final stages of a $1.2 billion tunnel project that will supply extra water to drought-hit Southern California. The 3.8-mile (6.1-km) tunnel, 1,500 feet below the San Bernardino Mountains, is the last piece of a 44-mile (71-km), three-tunnel system that will bring an additional 650 million gallons a day to 19 million Southern Californians. Twenty years in the making, the tunnels will almost triple the amount of water in Southern California's half-empty reservoirs when the project is up and running in 2010. "When water is available we must be prepared to move large volumes of water during a relatively short time and then store it for use during dry periods and emergencies." Climate change has meant less water from melting snow in the Sierra Mountains, one of the main sources of water in the state. This past March to June was THE DRIEST ON RECORD in that region. Levels in the state's two largest reservoirs are at 48 percent and 40 percent capacity - the LOWEST IN MORE THAN 30 YEARS - and are expected to drop further by the end of December.
Century-long droughts have occurred at least seven times across eastern North America. A new study confirms that during periods when Earth received less solar radiation, the Atlantic Ocean cooled, icebergs increased and precipitation amounts fell, creating a series of 100-year droughts. Every 1,500 years, weak solar activity caused by fluctuations in the sun’s magnetic fields cools the North Atlantic Ocean and creates more icebergs and ice rafting, or the movement of sediment to ocean floors. This climate cycle triggers droughts, including some that were particularly pronounced during the mid-Holocene period, about 6,300 to 4,200 years ago. These droughts lasted for decades or even entire centuries. Though modern records show that a cooling North Atlantic Ocean actually increases moisture and precipitation, the historic climate events were different. In the past, the tropical regions of the Atlantic Ocean also grew colder, creating a drier climate and prompting the series of droughts. The climate record suggests that North America could face a major drought event again in 500 to 1,000 years, though manmade global warming could offset the cycle. “Global warming will leave things like this in the dust. The natural oscillations here are nothing like what we would expect to see with global warming.”