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Thursday, June 22, 2006

News From My Backyard: Oregon and West Coast Should Brace for More Intense Storms Due to Global Climate Change

The Oregonian ran a front page, above-the-fold headline story in the most recent Sunday edition warning Oregonians and others living on the Pacific coast to brace for more intense storms in the near future due to global climate change and warming seas.

This article is a perfect example of how climate change will hit all of us ... in different ways for sure (we don't need to fear hurricanes like those in the Gulf Coast ... but we will all be effected nevertheless. That article, by Michael Milstein and Richard L. Hill appears below:

Early on Feb. 4, waves rose off the Oregon coast. And kept rising.

A cyclone churning from northeast of Hawaii whipped the sea into a frenzy. At 4 a.m., a yellow buoy bobbing 20 miles off Astoria measured waves averaging 33 feet high.

An hour later, the waves reached 34 feet, and at 6 a.m., a towering 45 feet -- the highest seas in the 22 years the buoy has been there.

The very biggest of the big waves, however, were monsters -- about as tall as a six-story building.

They slammed a massive jetty protecting the south entrance to the Columbia River, brushing away 20-ton boulders like pebbles and deepening a 50-foot gap. Winds blasted to 75 mph in Lincoln City, and water flooded streets and trashed homes in Washington. Coastal towns and 32,000 homes in the Willamette Valley lost power, bridges shut down, and falling trees closed roads and killed a Washington woman.

Oregonians should brace for more storms of such magnitude battering their scenic, rapidly developing coast as the sea rises higher than ever recorded and packs a more destructive punch.

As greenhouse gases trap more heat in the oceans and skies, fierce storms probably will increase, research predicts. They will whirl across seas brimming with water from melting ice caps, driving waves high enough to eat away beaches, highways and homes.

Storms have already strengthened, evidence shows, although the precise causes hide within an ever-changing web of weather. The state has started handing out a video to Oregon coastal home buyers warning of rising sea levels and mounting waves.

A rising sea, by itself, is not new. The ocean is up 400 feet since the most recent ice age began giving way to warming 20,000 years ago. Coastal campsites where some of the earliest Oregonians lived 10,000 years ago now lie a mile or two offshore, entombed underwater.

But as temperatures rise today, ice sheets covering Antarctica and Greenland are melting more rapidly than anticipated. And the rate of melt accelerates further, pushing the ocean upward.

Five years ago, the United Nations' Intergovernmental Panel on Climate Change projected sea levels could rise by as much as 3 feet by the end of the 21st century. But new research shows that estimate to be too low, and scientists say they probably will increase the figures when the panel releases its report next year.

Satellite measurements have found oceans rising by about a foot a decade over the past dozen years -- twice as fast as the rate recorded by tide gauges for the past 50 to 100 years.

But the Northwest coast has peculiarities. A geological shoving match between Earth's plates off Oregon and Washington now raises parts of the shoreline, keeping some places ahead of rising seas. A major earthquake could reverse that, however, by dropping the shoreline by as much as 6 feet to where it was 300 years ago, instantly raising sea level.

Tsunami zones at risk

The U.S. Geological Survey predicts the same low-lying areas at risk from tsunamis would be most threatened by changes in sea level and mounting storm waves. Those areas include all or parts of Rockaway Beach, Cannon Beach, Newport, Charleston, Coos Bay, Bandon, Pacific City, Waldport, Seaside, Tillamook, Salishan Spit and the Long Beach Peninsula.

Storm intensity and wave height are driven by changes in the climate, researchers say. It's impossible to pin it all on global warming, since storms like February's do not prove a trend on their own any more than a single rain shower proves a wet year. But it matches what sophisticated models of Earth's climate suggest will happen as the burning of fossil fuels drives up greenhouse gas levels.

"The one thing that's going to be noticed is larger, more intense storms," said Steven Lambert, a research scientist at the Canadian Centre for Climate Modelling and Analysis in Victoria, B.C. He has examined the question for 10 years and just published a study of storm intensity that found the greater the greenhouse gases, the more intense the storms that spin off the ocean.

"It may not be massive or sudden, and some people may not even realize it," he said.

Dan Cox, head of Oregon State University's wave laboratory, puts it another way: "We definitely should consider what's happening as much as we consider any natural disaster."

Three main forces shape the Oregon coast, says Paul Komar, an Oregon State professor who has studied the coast for decades: storms and weather patterns such as El Nino; waves; and sea level.

But global warming stands to reshape all three, which are connected to rising ocean temperatures.

The ocean is good at soaking up heat, which is why your hand plunged into cold water quickly turns numb. Millions of measurements around the world show that the oceans have taken up about 85 percent of the globe's excess heat in the past five decades -- roughly enough energy to power the United States for 1,400 years.

Only greenhouse gases caused by people burning fossil fuels can explain so much heat buildup, scientists say, making the rising ocean temperatures the "smoking gun" verifying a human contribution to global warming.

"We're seeing things that are unprecedented start to happen," said Sydney Levitus, director of the Ocean Climate Laboratory, a division of the National Oceanic and Atmospheric Administration.

The Pacific Ocean has absorbed about a quarter of the heat. Trade winds blowing west hold heat in the tropics around Indonesia. But new research shows those winds have weakened slightly in the past century and will ebb further as greenhouse gases rise. When ocean warmth escapes the winds, it surges toward the Americas in a phenomenon known as El Nino.

That raises sea levels along Oregon a foot or more and can invigorate storms that drive high winds and waves.

More El Ninos ahead

Scientists suspect global warming will make the Pacific more El Nino-like overall as it tries to shed its heat, said Kevin Trenberth, head of climate analysis at the National Center for Atmospheric Research.

"Riding on the warmer background state, even a minor El Nino of the future might seem strong by today's standards," said Andrew Wittenberg, a scientist at the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory.

Warmth, meanwhile, pushes up sea levels for two key reasons: Water expands as it absorbs more heat in a process called thermal expansion, and there is more water from the thawing of ice.

The result is that the Northwest may see a greater increase in sea level than in other parts of the world. A Canadian climate model that looked at only thermal expansion, not melting ice sheets, projects that the ocean off Oregon could rise by about 2 feet by 2100. By comparison, the northwest Atlantic would rise by a little more than 1 foot.

Places now only a foot or two above sea level will go under in the next few decades, said Peter Clark, a geosciences professor at Oregon State University. But the most-felt impact will be increased coastal erosion during winter storms.

Warming also injects the atmosphere with more moisture, a vital fuel for raging storms. The sky holds about 4 percent more water vapor now than in 1970, Trenberth said.

Hurricanes build from warm seas, but winter storms that strike Oregon are different. They swirl into being as polar cold clashes with tropical warmth. That clash probably will weaken as the poles warm faster than the tropics.

Oddly enough, that means fewer storms may start. But those that do may be more potent, leading climate models suggest. That's because winter storms, like hurricanes, feed off moisture in the air -- vacuuming up distant vapor as fuel. More moisture makes them rev up faster, spit more wind and rain and last longer, said Lambert, the climate research scientist from Victoria.

Studies as early as a decade ago spotted a trend of stronger storms in the Pacific after 1970. Scientists, a cautious bunch, warn that ocean cycles with no connection to global warming may be driving it. Records do not go back far enough to prove such upsurges haven't come and gone before.

"All the trends we've seen globally -- they all pretty much say (waves are) going up," said Val Swail, a wave expert with Canada's climate research agency. "The question is: Is this just part of a cycle, or is this a long-term trend?"

Climate models related to those that feed daily weather forecasts are good at predicting storms, Lambert says, although some scientists question whether they are detailed enough to capture a true picture of the future. Lambert suspects global warming is partly behind the rising storms, although there's no way to say how big a part.

Bigger, damaging waves

Some storms may never reach shore. But their winds can still whip up waves that do.

Northwest wave records through 1996 suggested that the most damaging waves in big storms should top 33 feet only once a century. In the next five years, however, they went higher than that at least five times -- severely eroding the Oregon and Washington coasts.

"We were rather taken aback," said Komar, the Oregon State professor. "Something was changing."

He and Jonathan Allan, a coastal geomorphologist with the Oregon Department of Geology and Mineral Industries, crunched records from buoys off the Oregon and Washington coasts. They found roughly an 8-foot upsurge in the larger winter waves hitting a buoy about 300 miles west of Astoria over the past 25 years -- giving the waves about 65 percent more force.

Allan and Komar have since revised the once-a-century wave height upward to about 52 feet.

The trend appears tied to escalating wind speeds and more powerful storms socking Oregon, they found. Their work has been backed up by other studies, including a Russian analysis of thousands of reports from ships dating to 1950.

The U.S. Army Corps of Engineers has watched rising waves batter jetties guarding the entrance to the Columbia River.

Repair work in the 1960s was designed for waves about 16 to 18 feet high, said Rod Moritz, a hydraulic engineer with the corps. He estimates waves hitting the same point on the jetty now approach 22 feet high.

"We're just seeing more of the extremes," he said.

The corps is spending $17 million on Band-Aid repairs to the south jetty this year and is considering broader repairs likely to cost much more. One catch: It's hard to find rocks big enough to withstand the higher waves, and to move them into place.

Erosion has always been a force on the Oregon coast. But the rising waves have reworked some shorelines so fast it's hard to keep up. At Cape Lookout State Park, one of the most popular playgrounds on the Oregon coast, waves have cut away 7 to 10 feet of some shorelines each year, exposing 1,400-year-old logs.

"What we're seeing is a new regime of conditions where the ocean processes have taken over," said Allan, who monitors the erosion.

The high waves may be driven by routine shifts of winds and currents, not greenhouse warming, scientists say. Escalating waves detected in the Atlantic tapered off and now appear unrelated to global warming. But new studies by the Canadian Climate Research Branch predict that higher waves will grow more common, especially on the West Coast, as greenhouse gases increase.

"We're beginning to get a picture that says, 'Yes, this is real. Things are changing,' " said Don Resio, a physical oceanographer and wave expert with the Army Corps of Engineers. "The whole global cycle is changing, and waves are part of that."

Oregon, meanwhile, is hardly ready for a rise in sea level.

"I don't think it's on anyone's radar screens," said Onno Husing, director of the Oregon Coastal Zone Management Association. "It's easy to get lulled into a false sense of security because of small increases in sea level, but those can lead to big impacts. So it's something everyone needs to start thinking about."

1 comment:

Anonymous said...

People need to respect nature instead of ignoring it, and taking advantage of our environment for selfish reasons. I don't understand how people can expect the earth to keep giving when we give nothing back.

Thanks for the post.