Warmer weather could bring big changes

Posted: Monday, April 09, 2001

A few degrees warmer: What Alaskan could ever complain about that?

One warm winter does not make a trend by any means, but the balmy weather is a reminder that scientists are speaking about climate change and predicting a conspicuous warming in most parts of the world in the decades to come. They warn that the changes will be greatest in polar regions and that Alaska may see major alterations.

Although impacts would be most severe in the arctic, where melting permafrost and sea ice could transform the landscape, the subarctic Kenai Peninsula would see big changes, too.

Some people question whether global warming is real or imaginary. But among climate scientists, a consensus seems to be building that trends are real and implications serious.

"The evidence keeps pouring in," said Orson Smith, a professor at the University of Alaska Anchorage with degrees in engineering and oceanography.

In 2000, he organized a conference in Anchorage titled "The Warming World: Effects on the Alaska Infrastructure" that attracted more than 100 scientists and engineers.

"I think it's pretty hard to deny that there is a climate change under way. ... I have seen dozens of credible presentations," he said.

"... At this point, I am convinced."

But one of those at the conference, Steve Boardman of the U.S. Army Corps of Engineers in Anchorage, remains skeptical.

"Global warming is, for lack of a better phrase, still speculative," he said.

"I have mixed feelings. ... Everything I have seen tells me we are in a cycle."

For Ed Berg, an ecologist at the Kenai National Wildlife Refuge, the question is moot. From his point of view, we already are dealing with the consequences of human-induced climate change.

Studying climate fluctuations is a hobby of his.

Global warming computer models predict winter temperatures will rise more than summer ones. Berg did a month-by-month comparison of temperature records at Kenai and Homer dating back to the early 20th century.

"Lo and behold, December and January had warmed the most," he said.

Two years ago he was predicting a run of cooler weather on the peninsula because of the Pacific Decadal Oscillation in ocean temperatures. Now he is wondering if that cycle will be late or not show up at all.

"In 1999, the temperatures went down. It looked like it was going to be a turning point in the PDO and the start of a cooling phase. But then (the temperatures) went up again the the next year."

And that was before the winter of 2001.

Meanwhile, the United Nations panel studying the issue came to an unambiguous conclusion after reviewing numerous studies. Part of its report, quoted in "Scientific American" said:

"Viewed as a whole, these results indicate that observed global warming over the past 100 years is larger than our current best estimates of natural climate variations over the last 600 years.

"More importantly, there is evidence of an emerging pattern of climate response to forcings by greenhouse gases and sulfate aerosols in the observed climate record. This evidence comes from the geographical, seasonal and vertical patterns of temperature change.

"Taken together, these results point toward a human influence on global climate."

A report posted on the Internet by the University of Alaska Fairbanks' Center for Global Change and Arctic System Research stated as facts that the carbon dioxide content of the atmosphere has increased about 20 percent since the beginning of the Industrial Revolution and attributed the increase to burning of fossil fuels and large-scale deforestation.

"Observations from meteorological stations in Alaska, northwest Canada and Siberia indicate that the annual mean temperature in these areas has become warmer by up to 1 degree centigrade per decade over the last 30 years or so, i.e. exceeding the rate of change predicted for the greenhouse effect, but is not necessarily due to the greenhouse effect alone," it said.

"Other indicators support this dramatic change. Permafrost is thawing throughout Alaska and Siberia, sea ice extent in the Bering Sea has shrunk by about 5 percent over the last 30 years and glaciers are melting."

But whether warmer weather would make the Kenai Peninsula toasty or toast remains to be seen.

Here are climate trends already seen on the Kenai Peninsula and their possible future directions:

n Glacial retreat

The glaciers on the Kenai Peninsula are shrinking.

Although warm weather in some situations causes glaciers to surge forward, that has not happened here, said Berg.

"We are definitely losing them," he said.

Skilak Glacier has retreated more than half a mile in the past decade. Grewingk Glacier near Homer has created a whole lake that wasn't on old maps. A 1984 study of the Harding Ice Field found the area it covered 5 percent smaller than in 1950, and a study in the mid-1990s concluded the ice sheet is 70 feet thinner than it was in 1950.

Berg said there is a real possibility the peninsula could eventually lose its ice field, but he would not hazard a guess as to when. The melting would depend on future temperature trends and the unknown terrain under the ice.

"It would be bad news to lose it completely. It would have a big impact on the Kenai River," he said.

"I figure after the Harding Ice Field is gone, the Kenai River is just down to a trickle."

n Drying

"This period of warm summers we've been having, especially since 1987, has been a pretty unbroken string," said Berg, who has been tracking long-term weather patterns and plant growth.

He finds the peninsula is drying out. Ponds noted on old maps are now grassy pans, young spruce are sprouting in former muskegs and the water level in many area lakes has dropped. Bernice Lake in Nikiski, for example, has dropped several feet, interfering with recreation there, he said.

Berg, noting that rainfall remains normal overall, attributes the drying to increased evaporation. The warmer the summer temperatures, the faster water evaporates.

That evaporation also effects plants and animals, especially during rainless periods. Habitat for wood frogs has shrunk, plants are stressed and everything becomes more vulnerable to disease, pests and fires. On the plus side, more fires and milder winters could mean more moose.

"I think the drying is the main effect," Berg said. "I think the bark beetles are a major consequence of that drying."

A drier peninsula also could diminish ground water availability. Some wells in the Homer area already have problems. If the peninsula's ice cover disappeared and the Kenai River dwindled, water shortages might eventually reach the central peninsula, he said.

n Productivity

Higher temperatures mean more plankton at the base of the food chain and more growing days.

The UAF global change Web site states that growing seasons are lengthening and boreal forests are expanding northward.

It predicts complex alterations in wildlife and fisheries, linked with more disease, movements of stocks and changed species distribution. It links high salmon catches in Alaska and lower ones farther south over the last quarter century with warmer ocean temperatures.

n Erosion

In early March, a Homer couple woke up after a storm and discovered that 20 feet of their beachfront yard was gone, crumbled into the sea overnight. The south peninsula community also is having problems this winter with sloughing from the bluffs overlooking the town.

Knowledgeable observers warn that warm, rainy weather has left bluffs along Cook Inlet soft and waterlogged, primed to wash away.

Boardman, who serves as chief of civil works project management on the peninsula for the Corps of Engineers, said frozen ground is more resistant to erosion during the spring and fall seasons of high tides and storms.

"The cohesiveness of the material provides a bit of extra protection," he said. "As those areas start to thaw, you lose structural integrity."

Water can lubricate the soil particles and undermine a bluff by removing material at its base, he said.

Global warming predictions also call for higher water and more storms. Boardman noted those could bode ill for efforts to stabilize the bluff at the mouth of the Kenai River.

"Erosion problems around Alaska are probably going to get more severe," he said.

n Wet weather

"There will be more precipitation, but because it is warmer, it will be more rain than snow," Smith said. "But at higher elevations there will be more snow load."

Winter rains and temperatures hovering near freezing lead to more potholes and road maintenance expenses, as seen on the central peninsula this winter.

More rain, combined with more storms, could increase flooding and erosion, but could help replenish ground water.

n Less sea ice

This winter, the U.S. Coast Guard has not had to issue heavy ice warnings for upper Cook Inlet. If the climate warms enough, sea ice may become a rarity around here.

"It forms later, it disappears sooner and it's thinner," Smith said.

In northern Alaska, loss of sea ice may mean loss of shorelines, more storm surges and loss of subsistence hunting access. But in Cook Inlet, it seems to be a plus, at least for the humans involved. Less sea ice means safer, quicker navigation for ships and fewer problems for offshore production facilities.

Milder winters could improve the viability of proposed projects in the upper inlet such as a port at Point MacKenzie, he said.



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