Blown away by stronger storms
4 September 2008
As Hurricane Gustav's rampage across the Caribbean and America comes to an end, a new study suggests the strongest hurricanes are getting more powerful. Is this a consequence of climate change? Antenna rides the storm to find out more...
This research was published in the journal Nature on 4 September 2008.
This research was published in the journal Nature on 4 September 2008.
Hurricane Gustav
Image: flickr.com Quiksilver1850
Recent years have seen New Orleans hit by hurricanes: Katrina in 2005 and this year Hurricane Gustav.
Image: flickr.com Spiritwood images
Scientists looked at 25 years of satellite data in the most extensive study of hurricanes yet. They noticed that although the strength of a regular hurricane hasn't changed, the biggest ones have got stronger. |
So why are they getting stronger?
The likely candidate is climate change. Hurricanes form as heated air rises up from the sea. As climate change warms the seas, more energy becomes available to power the hurricanes, resulting in greater wind speeds.
Hurricane Gustav on 30 August 2008 with winds of 240 km/h.
Image: NASA
The scientists found that on average a surface sea temperature rise of just 1 degree Celsius increased wind speed from 175 to 183 km/h. They also discovered that strong hurricanes became more frequent, increasing from 13 to 17 a year worldwide.
Hurricane hot spots shown on a satellite image.
Image: Wikipedia Commons
Why have only the strongest hurricanes got more powerful?
Scientist James Elsner explains: 'Other factors aside from sea temperature can contribute to the strength of a hurricane. The sun's intensity and the distance away from land have a greater influence than sea temperature on smaller hurricanes. However this is not well understood. Our next step is to explore these other factors.'
James Elsner, hurricane investigator, Florida State University.
Image: James Elsner
Is it just a load of hot air? We asked weather expert Gabriel Vecchi...
'This is the most convincing evidence yet that the world's strongest storms have strengthened. But this has not been confirmed worldwide and it's still unclear whether the effect is due to rising sea temperatures from global warming or something else.'
Gabriel Vecchi, expert on bad weather, National Oceanic and Atmospheric Administration.
Image: National Oceanic and Atmospheric Administration