UH to study how global warming affects isles

Small changes can have a huge impact on weather statewide

University of Hawaii researchers are planning some of the first studies of how global warming could change Hawaii's weather.

Small changes in ocean and air temperatures could produce dramatic changes in storms, rainfall and wind.

Scientists using computer models have been able to project the impact of global warming on large zones of the Earth. But until now they have been limited to 186-square-mile grids, said Kevin Hamilton, chairman of the department of meteorology.

Hamilton plans use information from the Japanese Meteorological Research Institute to analyze areas as small as 12 square miles.

That's small enough to pick up the nuances of Hawaii's "microclimates."

"With this high-resolution model, I could get forecasts differentiating between the Windward and Leeward sides," said Hamilton, who hopes that he and a post-doctoral student can complete a basic study this year.

Hamilton has received a $26,000 National Oceanic and Atmospheric Administration grant for the work, which also will be supported by the UH and Japan Agency for Marine-Earth Science and Technology, which jointly sponsor the International Pacific Research Center here.

Meanwhile, UH meteorology professor Thomas Schroeder hopes more research will be done on whether global warming might lead to less rainfall and a drier Hawaii by the end of the century.

Scientists already know that Hawaii gets less rain in El Nino years, Schroeder said. "There's a concept that climate change leads to a more El Nino-like environment," he said.

More detailed modeling might take a year and a $250,000 worth of computer time, Schroeder said, but the information is needed.

Climate researchers are trying to get clearer predictions of global warming effects because taking steps to reduce the warming trend -- such as tighter fossil-fuel emissions standards -- will be expensive, Hamilton said.

"The decisions we have to make are trillions-of-dollars decisions," he said. "If we're not well informed, it (the effects of global warming) could be very economically disastrous."

Hamilton's work will compare occurrences of severe winds or heavy rains in the 1990s with what models project for the 2090s.

A May 4 study in the scientific journal Nature used historic records and computer models to predict a 10 percent slowdown in the east-to-west winds near the equator by the end of the century.

Lead author Gabriel Vecchi of the NOAA Geophysical Fluid Dynamics Laboratory in Princeton, N.J., said his study could lay a groundwork for a closer look at Hawaii's weather and whether it could affect Hawaii's trade winds or increase rainfall.

But both Schroeder and Hamilton cautioned that Vecchi's study doesn't have a direct bearing on Hawaii weather because of the complexity of different air currents.

Vecchi agreed with the Hawaii scientists. He said he will next look into whether the slowing of winds along the equator could affect the biological productivity of fisheries and whether it would actually create more El Ninos.

The bottom line for the effects of global warming on Hawaii is that more research needs to be done, Schroeder said. "It would be crazy not to be interested in this if you're interested in the future of this place."

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