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Yesterday we reported how the warming seas are linked to the massive sea ice loss we've seen this year (possibly making 2008 the meltiest year on record). Well those warm seas are also changing things in the middle of the planet by making the strongest storms stronger. Data now shows that in the last 25 years, hurricanes, typhoons and cyclones have become more frequent in the tropics. Did we mention that 11 of the warmest years on record since 1850 have also occurred in the last 12 years? Hmm.
Scientists still debate whether the warming oceans also means more frequent storms - you need water temperatures of at least 80°F to make hurricanes, thus the warmer waters, the more storms. Professor James Elsner of Florida State University say that smaller, Category 1 storms don't show a signal or trend in the data, but as the winds increase there is a definite trend towards the warming oceans impacting the strength of the storms. The scientists also note that this trend is more apparent in the North Atlantic and Indian Oceans, but is absent in the South Pacific. This is because those water are already warmer than other areas of the Tropics and thus are not as affected by warming seas."The results are conclusive" says Professor Elsner, who published the study in Nature, "the stronger the cyclone, the greater the change." Weaker storms are not as affected because the conditions that cause them to get larger such as wind shears and shift in wind directions are not affected by warming oceans.
It is estimated that a 1°C rise in sea temperatures will increase strong storms by one third. Though other factors like proximity to land, El Nino, solar activity and cyclone origin and duration can also affect whether that storm takes off or not. "Strong storms seem able to overcome these factors and gather more fuel from warming waters" Elsner said. Thus its not the smaller storms we should be worried about but rather the bigger ones because the data now shows that they have a higher probability of getting even bigger.
:BBC::London Daily Telegraph:::Reuters
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