“Snowmageddon” and other powerful winter storms have blasted the United States, Europe, and Asia in recent years. Some scientists have suggested that such extreme weather events—such as those seen in this slideshow—are linked with rapid climate change in the Arctic, including dwindling sea ice. As more sea ice melts and Arctic amplification proceeds, it creates a smaller temperature gradient between the warmer Arctic and lower latitudes. That, in turn, slows down the jet stream, they argue, causing it to become more “wavy” and allowing colder air to penetrate farther south. But other researchers urge caution, questioning whether the data support this linkage, as Science reports today. They note we still have a lot to learn about the Arctic’s impact on the atmosphere.