Boston Globe: Large-scale projects that could temper or reverse the effects of climate change by blocking some incoming sunlight or manipulating the atmosphere have long been unpopular on two opposing fronts. On one side are those worried about the unintended consequences and doomsday scenarios that could be set off by careless experiments. On the other are those who believe such research is important, but to support it now will detract from the urgent need to cut greenhouse gas emissions that are driving global...