Hurricane Gustav: a signal of climate change?
As Hurricane Gustav approaches the coast of USA, with severe impacts expected in New Orleans almost exactly three years since Hurricane Katrina struck, we cannot help but start to question whether this is normal climate behaviour. Is this climate change rearing it's ugly head?
It is impossible for climate scientists to look at a particular tropical cyclone and say whether it is due to climate change or not. This is not how climate analysis works. Climate is average weather, and therefore to assess climate activity and how the climate varies, climate scientists must look at the statistics of average activity over a period of time. So, is global warming changing the frequency of tropical storms? Where they are making landfall? How intense the impacts of the storm will be?
To understand how global warming may be changing tropical cyclone activity, scientists are looking very carefully at the atmospheric and oceanic conditions that lead to the formation, the structure and the motion of these complex tropical features. Based on this work, there is much active research going on into tropical cyclones and how their behaviour may be changing. However, the global climate system is incredibly complex and tropical cyclones have a very delicate interaction with the background climate conditions. It is true that scientists are still trying to unravel how this complex relationship may be changing. Not only with global warming, but also with natural climate variability, such as the relationship between tropical cyclones and El Niño.
Scientists are using a combination of past storm data, state of the art climate models, and physical understanding to try and solve this puzzle, and we are starting to get some answers. But, while scientists are trying to solve this incredibly complex puzzle, it is inevitable that contradicting findings will emerge. This doesn't reveal that scientists don't agree or don't know what they are talking about. It just reflects the huge complexity of the science of tropical cyclones.
In terms of impacts, we also need to look at our own behaviour- a tropical cyclone only becomes a disaster when humans become involved. If we build oil platforms in the Gulf of Mexico, if we insist on developing Miami beach, if we continue living in New Orleans, we are increasing the risk and it is inevitable that the impact of tropical cyclones will increase. More money will be lost, and more people will suffer.
Dr Jane Strachan. Willis Research Fellow.
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Hurrican Gustav swept across the Atlantic in early September 2008.
The eye of the storm, which left nearly 90 people dead as it crossed the Caribbean, then headed across the Gulf of Mexico.
The worst of the storm made landfall west of New Orleans, sparing it from the kind of devastation wreaked by Hurricane Katrina three years ago.
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