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Isle climate
will dry, heat up,
expert predicts

Ocean warming means
'Honolulu might start hitting
90 degrees more often'

---

By Helen Altonn
Star-Bulletin

Hawaii's mild climate could change dramatically in the next 30 years because of ocean warming and drier conditions. Climate models show a significant 4 degree Fahrenheit increase in Hawaii's ocean temperature by 2030, says Anthony Barnston, director, Experimental Forecasting Division, International Research Institute for Climate Prediction at Columbia University.

"This means the high temperature in Honolulu might start hitting 90 degrees more often," he said, adding, "but it's a long way off."

Barnston was among delegates at the Workshop on Climate and Island Coastal Communities this week at the East-West Center. In an interview, he said models predicting ocean warming are based on a realistic 1 percent annual increase in carbon dioxide.

By Ken Sakamoto, Star-Bulletin
Recent rain caused Alenaio Stream in Hilo to flood, taking
out a large portion of Komohana Street. Weather experts say
Hawaii could see an increase in such heavy rainfall
due to global warming.

The trends already are under way, and "warming is pretty certain except for tiny places near Greenland" because of melting ice, Barnston said.

What's harder to predict are precipitation changes, he said, adding that most models show it will increase along the equator, near the international date line.

Increased moisture will occur when the ocean temperature surpasses 81 degrees Fahrenheit, creating a lot more rainfall, Barnston said. "It will be a little above it by 2030."

Increased rain is expected to accompany the warming in a horseshoe-shape area of the tropical Pacific, stretching east-northwest to the U.S.-Mexican border and to the southwest U.S. coast. The southern Cook Islands and French Polynesia are in the leg.

The Big Island could get more rain. However, drier conditions would occur in neighboring regions because of subsidence created by the increased upward motion and rainfall, Barnston said. In other words, "Rising air must fall somewhere else."

Models show a drying trend in the northern Hawaiian Islands; U.S.-affiliated islands west of Hawaii, including Fiji and Samoa; and the western portion of the Federated States of Micronesia, Barnston said.

"This is ominous," he said, pointing out that major populated islands are in the drying region. "Hawaii would be one of the losers in this scenario."

The scenarios now are just "best guesses," he said. But island communities should prepare for year-to-year changes because some very dry years will occur naturally, he stressed.

"It's important to mitigate losses in a drought. A lot of islands don't do much to prepare."

Pacific islanders should be educated about the issues and consulted about their traditions and folklore concerning climate predictions, Barnston said. They could help modern forecasters with predictions, but "we need to know which (traditions) work and how."