The Intergovernmental Panel on Climate Change was in a bind. The world's premier scientific body on the climate had found, in a 2013 report, that it is extremely likely that human activities are responsible for most of the observed warming of global temperatures since 1951. Yet the public did not seem to care. So the IPCC scientists switched tacks. At a press conference on their report, they emphasized the record warmth the world had experienced in the past decade. But by referring to a decadelong stretch of warming, the IPCC scientists may have unwittingly sowed the seeds of confusion, according to a study published yesterday in Nature Climate Change.