Bloomberg reports that a slowing jet stream might be causing longer-lasting storms and heat waves, according to a study published in Nature this year. Study author Michael Mann, an atmospheric scientist at Pennsylvania State University, told Bloomberg that sometimes currents in the upper atmosphere go through a stationary phase that may be linked to longer-lasting weather disasters and "appears to be favored by human-caused climate change."

What they did: The scientists analyzed a number of extreme weather events, including Russia's 2010 heatwave, flooding in Pakistan in 2010, and the recent droughts in Texas and California. They found the jet stream stabilized during some of those cases, possibly holding the weather patterns in place.

A link to Harvey? On Monday, Mann published an essay detailing different ways climate change may have had an impact on Harvey. Although he mentioned jet stream stalling as a potential factor contributing to Harvey's persistence, he described the link as "tenuous."

The remaining question is whether the disruptions in the jet stream are caused by Arctic warming, which is occurring at twice the global average and could create opportunities for more persistent weather farther south. Even then, there is debate over whether there is a link between jet stream sluggishness and major storms at all. "It's still controversial," David Sobel, an earth scientist at Columbia University tells Bloomberg.