Scientists at Rutgers and Wisconsin universities are linking climate change and extreme weather, such as this winter’s persistent cold snaps gripping the Lehigh Valley and beyond… Specifically, the jet stream that pushes weather systems across North America has been varying more wildly and more often since the 1990s, according to an article published Wednesday in Rutgers Today. A new study, published in IOPscience, by Rutgers climate scientist Jennifer Francis and University of Wisconsin-Madison scientist Stephen Vavrus ties the “wavy jet stream to a warming Arctic, where climate changes near the top of the world are happening faster than in Earth’s middle latitudes,” Rutgers Today reports… “The recent changes we’ve seen are clearly linked to increasing greenhouse gases, and there’s no sign of abatement in our use of fossil fuels,” Francis told Rutgers Today, noting that during that ancient period the Earth was several degrees warmer than now and sea levels were several meters higher.