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Global warming bodes
ill for isle weather,
economy

Typhoon Tokage lashed western Japan yesterday with enormous waves, torrential rains and landslides, leaving at least 15 dead and 20 missing. Typhoon Tokage, the record 10th typhoon to make landfall in Japan this year, follows less than two weeks after Ma-On, the strongest typhoon to strike eastern Japan in more than a decade. In all, storms and floods have killed no less than 79 people in Japan this year and caused billions of dollars in damage.

Closer to home, Hurricane Jeanne was the fourth major hurricane to strike Florida this year, also a record number of landfalls for one season. It is well established that the fuel driving hurricane (and typhoon) intensity is the warmth of the near-surface ocean water. As the surface temperatures of the oceans in the tropics and subtropics rise as a consequence of global warming, it is reasonable to expect stronger and perhaps more numerous hurricanes.

The amount of water vapor the air can hold increases exponentially with increasing air temperature. When water vapor condenses into clouds, heat released into the air adds to the air's buoyancy, fueling the cloudy updrafts. As a result, global warming has two somewhat contradictory consequences:

» stronger thunderstorms and hurricanes, and more flooding in regions where water vapor is abundant;

» increasingly severe droughts (and fires) in locations more removed from a source of water vapor.

The consequences of global warming are usually phrased in terms of average temperature and a rising of the ocean surface. The consequences of these factors can be substantial (consider how vulnerable Waikiki is to a rise in sea level), but these changes are gradual and in some cases mitigating actions may be taken.

The fact that more severe weather events also are related to global warming has not received as much attention and is much more difficult to quantify. It is possible that the extreme combination of events in Japan and Florida is an unusual fluctuation in the current weather, but it is a clear warning of what will become normal in the future. The consequences for Hawaii are sobering.

Based on the overwhelming evidence for warming of the Earth's climate (see September's issue of National Geographic), British Prime Minister Tony Blair recently issued an emphatic call for the developed nations to reduce man's impact on the atmosphere to help mitigate the consequences of global warming for future generations. The recent hurricanes and mounting signs of a warmer Earth provide food for thought. Our actions in Hawaii, which consume energy and resources, contribute to global warming that will come home to our children.

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