S Atlantic Hurricane - Global Warming is Worsening? |
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Written by spacetravel.org
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Wednesday, 28 September 2005 22:10 |
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Hurricane Catarina, not to be confused with Katrina, struck the southern coast of Brazil in March 2004. While hurricanes, such as Katrina, have struck the south-eastern coast of the US before, Catarina is the first and only hurricane recorded in the South Atlantic, where according to textbooks, hurricanes should not form. Some experts believe that the appearance of hurricane Catarina could be evidence that global warming is creating more extreme weather conditions.
Climate models from the UK Met Offices Hadley Centre for Climate Prediction and Research, based in Exeter, predict that the region of the South Atlantic where Catarina developed will eventually be the source of many hurricanes. It is believed that global warming will raise local sea temperatures, causing more water vapour to evaporate from the surface of the ocean, then condense in the air and release heat, fuelling tropical storms in the region. However, the Hadley centre models do not show this happening until 2070. So Catarinas appearance could mean that global warming is happening at a faster pace than expected.
In another global warming study, published last week, Holland and Peter Webster and Judy Curry of the Georgia Institute of Technology in Atlanta showed that in the past 35 years, the number of strong hurricanes has nearly doubled, while the proportion of hurricanes with wind speeds over 56 metres per second has increased from 20 to 35 percent since the 1970s. The report states that natural fluctuations such as El Niño and the North Atlantic Oscillation could not have caused these changes, since these fluctuations tend to be localised and short-term, and would not last 35 years. Instead, it speculates that the stronger hurricanes are linked to a 0.5ºC warming of surface ocean temperatures in the tropics.
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