The jet streams in both hemispheres have risen in altitude and shifted toward the poles over the past two decades. The movement can have significant impact on weather around the globe if it continues, according to research published in the April 18 Geophysical Research Letters.

While the jet streams twist and turn as they move across the sky, they do have an average position and strength. It was these averages that researchers from the Carnegie Institution’s Department of Global Ecology studied. Their findings are in line with other signals of global warming found in other studies. From observation-based data (from weather balloons, satellites, surface instruments and other sources) the Carnegie researchers report streams in the northern hemisphere are shifting toward the North Pole about 12 miles per decade.

 The results could be a northward shift for storm paths in North America and more powerful and more frequent hurricanes. “The jet streams are the driving factor for weather in half of the globe,” says Cristina Archer, co-author of the research. “So, as you can imagine, changes in the jets have the potential to affect large populations and major climate systems.” Her co-author, Ken Caldeira, adds, “At this point we can’t say for sure that this is the result of global warming, but I think it is. I would bet that the trend in the jet streams’ positions will continue. It is something I’d put my money on.”