Drowning Hawaii Under Sea Level Rise
By Diana Leone - Honolulu Star-Bulletin Sunday, September 23,
2007
It doesn't have the sudden terror of a tsunami or a
hurricane. But the sea level around Hawaii is expected to rise 39 inches by the
end of the century.
It will come slowly. And once it comes, the water will stay
a long, long time.
It will submerge the Ala Wai Boat Harbor, the Hilton
Hawaiian Village Lagoon, the banks of the Ala Wai Canal and most of the Ala Wai
Golf Course.
Magic Island will be an actual island.
Industrial sites at Campbell Industrial Park will have water
lapping at their foundations.
Beaches will be going, going and gone.
Coastal communities throughout the state will be forced to
move, raise and abandon buildings and roads that are too close to the rising
waters.
"I think this is a slowly emerging catastrophe,"
geologist Charles "Chip" Fletcher said. "I think it's going to
slowly dawn on us."
And this amount of sea level rise is coming, Fletcher said,
even if the world takes quick action to slow global warming, because the
climate changes are already in motion.
What's in store for
Hawaii
What would a 39-inch rise in sea level mean
for Hawaii? Charles "Chip" Fletcher from the University of
Hawaii-Manoa's School of Ocean and Earth Science and Technology predicts:
» In the coming decades,
the rising water table will form permanent wetlands, including in urban areas,
from which rainfall and storm runoff will not drain.
» Heavy rain, such as in
the winter of 2006, will cause flooding lasting weeks.
» Erosion of beaches and
other non-rocky shorelines will accelerate.
» High waves will
increasingly damage roads and communities near the coast.
» Sea level rise will
magnify the effects of storm surge, hurricanes and tsunamis, causing more
damage farther inland.
With worldwide action to slow global warming, "I think
the potential exists for us to stop it at a meter or a meter and a half,"
he said.
Fletcher's University of Hawaii research team has created
aerial maps that depict downtown Honolulu, Waikiki and Kalaeloa as they would
look with a one-meter rise in sea level.
The first signs of the change are already here.
During a monthly high tide, "go to Coral Street or
Mapunapuna or in Waikiki and pull up a manhole cover and you'll see salt water
less than a foot below," Fletcher said.
On Nov. 23, the highest tide of the year, Fletcher predicts
sea water will flow out of storm drains on the sides of Ala Wai Boulevard.
"That's going to be the first sense of sea level rise
that most people have, pools of water pool around storm drains," Fletcher
said. "And if it rains on top of that, rainwater has nowhere to go, so it
will puddle."
Like the low
spot on Mapunapuna Road that periodically floods when high tides and heavy
rains converge.
Unless there are engineering projects to avert it, such
places will become what Fletcher calls "urban wetlands" in coming
decades.
"If you look at this map of Waikiki, it's quite obvious
that Waikiki at high tide, several decades from now, or at end of the century
can't exist the way it is right now," Fletcher said.
Ditto for coastal highways in places where they have been
flooded by high surf every couple of years. That will start happening several
times a year, agreed Cheryl Anderson, director of the Hazards, Climate and
Environment Program at the UH's Social Science Institute.
Government agencies are in the early stages of "working
with development plans to think about what these changes might mean,"
Anderson said.
The 2007 draft revision of the state's Hazard Mitigation
Plan, a document required by the Federal Emergency Management Agency to get
federal disaster aid, has a new section on climate change, including sea level
changes, Anderson said.
In addition to speeding beach erosion, the higher ocean
could also more frequently overtop protective reefs during storms -- making
wave run-ups go even higher.
"The good news is that it's still a ways off,"
said Bruce Richmond, U.S. Geological Service specialist in coastal hazards.
"We can start to plan for this when we build new highways and
construction."
"We're looking at a long-term phased retreat from the
coastline," Richmond said. "It starts with zoning and setbacks, so
that large expensive public buildings are not put right on the water's
edge." Insurance policies that allow rebuilding of damaged structures will
have to be re-examined.
"There's plenty of time to adjust to this,"
Fletcher said. "If we are proactive, we can really begin to get a handle
on this problem."
Fletcher suggests that:
» Waikiki hotels include sea level rise countermeasures when
major renovations are undertaken.
» Somebody drill dozens of test wells in downtown Honolulu
and Waikiki to locate the water table and forecast where its rise with the
ocean level will cause problems.
» Too-close-to-the-ocean highways be shifted mauka to avoid
the rising water.
The state Transportation Department is aware of the sea
level rise trend, but is dealing with it by addressing coastal highways that
are suffer from high surf erosion now, spokesman Scott Ishikawa said.
A recent
example of a fix was the Kalanianaole Highway at Makapuu. On the drawing board
for possible movement inland are the Laniakea area on Oahu's North Shore, the
Honoapiilani Highway south of Lahaina, and the Hilo Bayfront Highway, Ishikawa
said.
The department also is studying trouble spots on the
Kamehameha Highway on Oahu's Windward side, he said.
Hilo's pull-back from the ocean after the 1960 tsunami exemplifies
changes that eventually might have to be made at vulnerable spots, Anderson
said.
Eileen Shea, director of the NOAA (National Oceanic and
Atmospheric Administration) Integrated Data and Environmental Applications
Center, praised Fletcher's map as a "a first blush snapshot" that
should lead to more in-depth study.
"You and I aren't going to feel the average sea level
rise," Shea said. "What we're going to see is how they're going to
affect extreme events," because even a few inches of higher sea level can
magnify the bad effects of hurricanes and high surf.
"We don't want to create a panic, but we need to make
everyone aware that it's something we need to plan for in the future,"
said Sam Lemmo, administrator of the state Office of Conservation and Coastal
Lands.
Some signs that Hawaii
government officials are beginning to take action:
» Studies of coastal
erosion trends have been completed on Maui and are ongoing on Oahu and Kauai.
These are used to determine how close to the coast new buildings are allowed.
» The U.S. Geological
Survey could begin new studies soon on the effect of sea level rise on coastal
areas, including Hawaii.
» Congress will consider
requiring states to conduct climate change planning.
» State and federal
agencies have jointly printed several books that include information about sea
level rise, such as coastal hazard mitigation, coastal erosion and what to look
for when buying coastal real estate.
