By Tobias Carroll As scientists and engineers work to address the effects of climate change and reduce harmful emissions, a significant question hovers over the proceedings: is it possible to find an alternative to fossil fuels that doesn’t pose serious drawbacks? There isn’t an easy answer to this — and the process of determining what trade-offs are acceptable presents its own challenges. Now, a scientific breakthrough might have opened the door to a source of clean power located deep underground. And in this case, “deep” means “several miles down.” As a recent Boston Globe article explains, …