Jet stream changes everything?
High-altitude bands of fast winds that drive the paths of storms and other weather systems are now shifting - possibly in response to global warming.
The Jet Stream is a fast moving ribbon of air high up in the atmosphere (not to be confused with the Gulf Stream, an ocean current in the Atlantic).
These ribbons are only a few miles wide at a height above 20,000 feet (3 to 4 miles) and can have wind speeds of 300 to 400mph!
shoved about
Their position is not static: they twist and turn, changing route every day within a known band. However, research at the Carnegie Institution has found that between 1979 and 2001 (a 23-year span) the jet streams in both hemispheres have shifted toward the poles. They have both have risen in altitude, too. The jet stream in the northern hemisphere has also weakened.
These changes fit the predictions of global warming models and have implications for the frequency and intensity of future storms, including hurricanes.
The jet streams are the driving factor for weather in half the globe, so these changes could affect large populations and major climate systems.
weather bombs
The UK’s storms in early March this year were examples of a rare weather “bomb”. This is a tempest that explodes into life at a ferocious rate, and can catch weather forecasters unawares like the notorious storm of October 1987. The jet stream is the engine that drives these sudden extreme weather incidents.
Storm paths in North America are likely to shift northward as a result of the jet stream changes. Hurricanes, whose development tends to be inhibited by jet streams, may become more powerful and more frequent as the jet streams move away from the sub-tropical zones where hurricanes are born.
worse hurricanes
Hurricanes have been growing more fierce over the past 30 years.
Analysis of tropical hurricane records found that both the duration of the storms and their maximum wind speeds has increased by about 50 per cent since the mid-1970s. Moreover, this marked increase in the energy release has occurred in both the north Atlantic and the north Pacific Oceans.
Hurricanes account for a significant amount of the damage, injury and loss of life from natural hazards, and are the costliest natural catastrophes in the United States. As the coastal region populations get denser, damage and casualties from more intense storms could increase considerably in the future.
current changes
A new study finds that the warm Gulf Stream current has more influence than previously thought. By pumping heat high into the atmosphere along its course from the Gulf of Mexico to the European coast, it could influence the climate of remote regions. Japanese researchers have combined high-resolution satellite data with water analyses, and discovered a pattern of airflow that reaches seven miles (10 kilometers) high - well past the Jet Streams.
Ironically, climate change is predicted to slow the Gulf Stream down, which will warm up the Gulf of Mexico, making highly temperature-sensitivehurricanes fiercer.
Opinion:
It is getting easier to understand how different parts of the planet’s environment affect each other. We may be no nearer controlling the weather systems, but we can monitor, and perhaps predict large-scale changes.
The scale of these forces in our environment should humble us.
These changes should warn us that our selfish search for luxury is pushing us to the edge of survival.
Rachel Carson said in her speech “Of Man and the Stream of Time” in 1962 that “Man’s heedless and destructive acts enter into the vast cycles of the earth and in time return to him.” [more]
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