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No Answers. Other scientists are studying the sun to determine if its energy output is constant and if there is any link between sunspots (caused by magnetic storms on the sun's surface) and droughts, which often occur every other time the eleven-year cycle of sunspots reaches its low point. Other investigations—of ocean and atmospheric circulation, the processes of mountain building, the influence of land masses—are all pointed toward a better understanding of global climate. That understanding is sorely needed. "Our knowledge of the mechanisms of climatic change is at least as fragmentary as our data," says a report published last year by the National Academy of Sciences. "Not only are the basic scientific questions largely unanswered, but in many cases we do not know enough to pose the key questions."