what are the long term change that can be seen in it according to scientists?
Climate scientists have hypothesized that the jet stream will gradually weaken as a result of global warming.
Jet stream
Climate scientists have hypothesized that the jet stream will gradually weaken as a result of global warming. 
where are the two main hemispheric jet streams located The polar jets, at above sea level, and the higher altitude what is it? A Jet stream can you define it? Jet streams are fast flowing, narrow, meandering air currents in the atmospheres of some planets, including Earth what are its applications? Aviation and weather forecasting
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Jet stream [SEP] Longer-term climatic changes
Climate scientists have hypothesized that the jet stream will gradually weaken as a result of global warming. Trends such as Arctic sea ice decline, reduced snow cover, evapotranspiration patterns, and other weather anomalies have caused the Arctic to heat up faster than other parts of the globe (polar amplification). This in turn reduces the temperature gradient that drives jet stream winds, which may eventually cause the jet stream to become weaker and more variable in its course. As a consequence, extreme winter weather is expected to become more frequent. With a weaker jet stream, the Polar vortex has a higher probability to leak out of the polar area and bring extremely cold weather to the middle latitude regions.