Wind speeds across the seas are increasing

27 March 2011


Researchers have reported this week that wind speeds across the oceans have increased, on average, by at least 0.25 per cent each year for the past 23 years.

We don't know whether this is linked to climate change, but Ian Young from the University of Technology in Melbourne claims that it's an important but often overlooked variable in climate change studies.

Increase in extreme wave height

Publishing in the journal Science this week, the team used satellite data taken predominantly from GEOSAT altimeter readings, which they pieced together. They found that wind speeds are increasing more in the southern hemisphere than they are in the north and that the more extreme wind speeds are increasing by 0.75 per cent per year. Overall, a quarter of a percent each year doesn't sound like that much but it adds up to an increase, in the last 23 years, of between 5 and 10 per cent.

The effects of this could be bigger waves, but the team found no statistically significant growth in wave height over the past two decades. The heights of northern hemisphere waves seemed to be getting only very slightly smaller and the southern hemisphere waves were only getting slightly bigger. But neither of these changes were significant. And the researchers point out that this indicates wave height is determined by far more than just wind speeds, with other factors including swell and fetch.

On the other hand, the largest waves in higher latitudes do seem to be increasing in height. And the authors point out that, in more extreme conditions, this relationship between wind speed and wave height becomes more apparent. So you could argue that, if wind speeds across the oceans continue to increase, the largest waves would grow even bigger.  This could potentially affect how humans are able to exploit the sea: affecting fishing and shipping. Or it could be a positive boon to our efforts in wind farming.


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