This paper was written as part of the 2005 Alaska Ocean Sciences Bowl high school competition. The conclusions in this report are solely those of the student authors.
Global Climate Change and its Effect on Our Coastal Community
The climate of the earth is getting warmer and significant environmental changes are occurring. Research indicates this is occurring at a faster rate each year. The first major signs being detected are in the high latitudes such as Alaska. The glaciers, tree lines, ground water, and water drainage systems are all being affected with consequential effects on the flora and fauna.
The local economy of the Kenai Peninsula is directly tied to these resources and their ability to attract tourists. The major resource depended upon is the wild salmon stock, which may be drastically affected by the global climate crisis. To prepare for this impending possibility, we have chosen a multi-path approach. We propose to inform the public with a public service radio announcement, develop a website to explain the problems, and encourage diversification and development of our other natural resources. In addition, we propose to supply nutrients to systems that are adversely impacted by lower numbers of salmon returning to them.
Since the late 1800s, temperatures at Earth's surface temperatures have risen significantly, partially due to the increasing levels of ozone in the atmosphere (Jacobs et. al., 2004). Troposphere ozone, or lower level ozone, is considered a greenhouse gas, meaning it traps and retains heat from the sun. Other common greenhouse gases include carbon dioxide, methane, nitrogen oxides, and even water vapor (Nardo, 1991).
Alaska has experienced the largest regional warming of any state in the United States with an average rise of 3°C since the 1960's and 4.5°C in winter. For Alaska, two general circulation models have generally been used to predict future climate changes: the Canadian Climate Model and the Hadley Center Model. Within Cook Inlet, the Canadian model predicts the largest increase in air temperature, ranging from 5°C to 10°C, by the year 2100. Precipitation is projected to increase by 20-25 % (USGS, 2001).
Skyview High School, located in Soldotna, Alaska, lies in the heart of the Kenai Peninsula (Figure 1). The 16,013 square mile landmass that makes up the Kenai Peninsula is bordered directly by the Gulf of Alaska on the eastern side and Upper Cook Inlet (UCI) on the western side. There are approximately 52,000 people on the peninsula (Census, 2002). In addition to local residents, the population increases two to three times during the tourist and recreational use periods of May to August. The people of the Kenai Peninsula Borough (KPB) value their natural environment. Beatty et al. (2002) found that every age group of people living in the KPB felt that protecting wildlife was a greater priority than economic development.
Following is a discussion of impacts of the global temperature crisis on the KPB.
In Alaska, glaciers are receding at an increasingly rapid rate each year due to the rise in temperature (Figure 2, Berg, 2004). Since the 1980's, peninsula glaciers have been rapidly growing smaller. For example, Exit Glacier is receding 43 feet each year and the Harding Ice field has lost 5% of its mass (Berg, personal communication, 2004).
The combined impact of this rapid melt is significant. Increased flows of glacial rivers have been measured along the whole Alaskan coast. These flows not only increase silt loads within the main stem glacial systems but also are having a significant impact on the band of low salinity coastal water along the Gulf coast. This band is getting wider and, in some cases, blocking the flow of productive marine waters into coastal areas like Prince Williams Sound (Okkonen, 2004).
The euphotic zone depth (EZD), the water depth in lakes where sunlight is sufficient for photosynthesis to occur, is inversely impacted by the turbidity of the water. The increased rate of glacial melt raises the turbidity of glacial streams, rivers, and lakes and therefore decreases the depth at which light can penetrate.
Less light means a reduction in phytoplankton and photosynthesis, which translates to less zooplankton, which are the primary food resource for rearing sockeye salmon populations (Tarbox, 2004). For example, in Skilak Lake, a large glacial lake on the Kenai Peninsula, the EZD measurements by the Alaska Department of Fish and Game (ADF&G) indicated that since the mid 1980's, there has been a reduction in EZD from 12m to 4m in 1995 but has generally increased since then (Figure 3).
Drying of Fresh Water Streams
Though a significant reduction in precipitation has not been noted on the Kenai Peninsula accompanying the temperature increase, a drought is taking place (Berg, 2004, Figure 4). This has been caused by an increase in the rate of evaporation (Okkonen, 2004). Hundreds of small streams are fed by rainfall and snow melt each year, so many of these small tributary streams are drying (Okkonen, 2004). The significance of this is a decrease in freshwater fish spawning ground and habitat, along with less fresh water for wildlife to use for nesting, rearing, or consumption.
Kettle Lakes and Wetland Drying
A kettle lake is a lake formed when a piece of ice is left behind by the main mass of a glacier and sinks below ground level and melts, leaving an indention in the land. Once the ground water level rises, a lake is formed. Most of the lakes in Alaska are considered kettle lakes. In recent decades, KPB residents have noted that the kettle lakes have been drying out indicating a significant change in the ecosystem. Figure 5 shows a kettle lake in our area that has dried significantly. While this does not directly affect the Kenai River watershed, it does indicate that we are experiencing a drought.
Spruce Bark Beetle Infestation
Another indicator that we are undergoing a fluctuation from the regular climate pattern can be seen in the outbreak of the bark beetle population. The normal hatch-cycle of the spruce-bark beetle takes two years (Berg, 2004). Warm, dry weather shortens the gestation period of the eggs and speeds up the growth of the beetle larvae, causing a population outbreak. Areas where such outbreaks occur are referred to as Red Needle areas (Figure 6). ADF&G reported recently that the level of spruce bark beetle activity in South-central Alaska increased to 1 million acres of active infestation from 545,000 acres in 1997 (Moss and Thomas, 2000).
Rising Tree Line
The average tree line elevation in south central Alaska is 3500 feet. Trees and shrubbery mingle along this line with fewer trees growing as the elevation increases. The trees that are present are mangled, warped, and stunted. In warmer climates, the tree line extends to a higher elevation. In recent years, it has been noted that the trees high on the line in Alaska are beginning to grow straight up, rather than along the ground (Berg, 2004). This further illustrates that the climate has drastically changed.
The Most Significant Impact
After careful review of impacts of global temperature increases on the Kenai Peninsula, we determined the impacts on salmon production in the Upper Cook Inlet to be the primary concern. Salmon are an integral part of the KPB economy and ecosystem.
In addition to published figures on the economic contribution of salmon to the local area, we conducted a survey (Appendix A) of bed and breakfast owners in our area to assess the level of importance of salmon fishing to their business. We surveyed 27 bed and breakfast businesses, the results are presented in Figure 7. We conclude that a majority of tourists visit the Kenai Peninsula specifically to fish. Seventy nine percent of tourists came for fishing, 3.6% for bird watching, 11.4% for general wildlife viewing, 1% for business, 1.2% for trail hiking, and 3.8% for other reasons. Over 79% of these bed and breakfast operators believe these numbers are not changing but are staying the same. If salmon were to decrease, 63.1% of the owners of the bed and breakfasts look to an increase in general wildlife viewing to enhance their business.
Relative to ecosystem functions, salmon are a key species. For example, salmon provide an important source of food to Kenai Peninsula brown bears and provide marine nutrients to freshwater ecosystems, a biofeedback loop that is important to overall ecosystem health (Bisgard et al, 2001).
All five species of Pacific salmon are found on the Kenai Peninsula. Most salmon species spawn in the fall (August to September) and the eggs develop over winter. The hatching takes place in January to February and the fry stay in the gravel for three to six weeks. At this point, each species of salmon use a different type of habitat for rearing. Coho salmon move from spawning areas to slower moving water for freshwater rearing such as beaver dam lakes and small kettle lakes. Chinook salmon, in contrast, tend to stay in faster moving waters and orient toward the banks, where overhanging vegetation provides shelter and food. Sockeye salmon move both upstream and downstream to rear in both large glacial lake systems and clear water lakes. Pink and chum do not rear in freshwater, but move directly to the estuarine area immediately upon leaving the gravel (Groot et al. 1995: Groot et. al. 1991).
Since temperature rises impact all salmon in UCI, we chose the Kenai River system as a specific example. Few residents of the KPB realize that 70%-80% of sockeye salmon returning to the Kenai River as adults, rear in Skilak Lake, a large glacial system. Chinook salmon in the Kenai River composes two runs: an early run which enters the river in May and June, and a late run that enters in July or August. Early run chinook salmon spawn mainly in the tributaries, such as Slikok Creek, Soldotna Creek, Funny River, and the Killy River. Late run chinook spawn in the main stem Kenai River. Juvenile coho salmon also enter in two distinct time period: August/September and late September/October. Early fish, like chinook salmon, spawn in the tributaries and late run fish spawn in the main stem. Coho salmon migrate extensively throughout the system. They rear and over-winter primarily in the Moose River system (Tarbox, 2004).
The impact of global temperature increases on Kenai River sockeye salmon is not at first obvious as adult sockeye salmon spawn in the main stem Kenai River and rear in the large glacial lake systems. These systems buffer direct temperature influences on salmon as they remain relatively cold. However, indirect impacts are significant. Observations by local hydrologists indicate that May/June Kenai River glacial flows have increased and associated with this is an increased in near shore water velocities. In addition, as previously noted the EZD had decreased in Skilak Lake and with it primary and secondary production figure 4; (Ruffner, 2004; Edmundson et al. 2003; Willette, 2004).
Sockeye salmon fry, 25mm, migrate upstream to Skilak Lake from outlet spawning areas. The migration path is along the near shore areas where current velocities are minimal in May. The energy expended by these fry to migrate at significantly higher flow rates may reduce overall survival as additional energy is depleted.
More significantly is the impact of temperature increases on glacial melt and the resultant increase in turbidity levels and decrease in EZD. "Euphotic zone depth in Skilak Lake was correlated with cyclops biomass indicating that light penetration affected primary and secondary production," noted Edmundson et al. (2003). "Also, copepod biomass was correlated with fall fry abundance and size, which was in turn related to over winter mortality of fry. These relationships are evidence of mechanisms that cause limitations in primary production to affect survival of sockeye salmon. Such mechanisms exist, because food abundance limits the growth of juvenile sockeye salmon in this system. Thus, large escapements and especially consecutive large escapements have the potential to substantially reduce stock productivity, and this potential is much greater when light penetration and primary production are reduced by elevated glacial runoff".
The above variables have been modeled and projected to show the impact of decreased EZD on Kenai River sockeye salmon adult numbers by Willette (personal communication, 2004). He found that at an EZD of 12 m, the average return of sockeye salmon would be 4.9 million at spawning escapements of 700,000 fish, with a harvest of 4.2 million. The potential for a harvest of less than 1 million fish was 0.6%. In contrast, at an EZD of 4m and a similar spawning escapement, the return is decreased to 2.4 million with a 1.7 million fish harvest. The probability of a harvest less than 1 million fish increased to 21.5% (Figure 8). During the 1980's, the EZD of Skilak Lake was closer to 8-12 m, as opposed to more recent measurements of 4-6m in the late 1990's.
Chinook and coho salmon spawn in some of the smaller tributaries to the Kenai River system, such as Slikok Creek. In 2004, a year that was significantly warmer than normal, approximately 0.75 miles of Slikok Creek went dry (Ruffner, 2004). This took place at a time when adult chinook salmon were migrating upstream to spawn. This was an obvious block to migration of both adult and juvenile fish.
Chinook and coho salmon fry also emerge in May and June from the spawning gravels and disperse through out the river system. Higher mainstem flows may require more energy expenditure to maintain position in the current and fry may be swept out to sea as they become weaker. In addition, the reduction in flows in the freshwater tributary systems may reduce habitat availability as surface water levels decrease. Recent studies of streams on the lower peninsula indicated that water temperatures exceeded levels that are good for salmon spawning and rearing.
In summary, it is anticipated that overall salmon production on the Kenai Peninsula will decrease with the projected global temperature increases. We project that the following impact on our community and ecosystems will take place as a result of poor salmon returns.
First, the most obvious impact will be the reduction of fish available for harvest. Presently, the sport and personal use fisheries for sockeye salmon from the Kenai River harvest 600,000 fish (Fox, 2004). If this level of harvest were maintained, only 400,000 fish would be left for the commercial fishery; that is if harvest levels reach less than 1 million fish as projected. That would not sustain this industry (Maw, 2004). In contrast, if a commercial priority were given, the sport fishery and personal use fisheries would suffer along with the businesses that count on them.
Relative to other sport fisheries, the decrease in chinook and coho salmon production may make these fisheries less attractive to sport fisherman. For example, in the early run chinook salmon fishery, the ADF&G has had to close the fishery numerous times in the past 20 years because of poor returns. This has already caused an impact on the economy of the local area and further restrictions because of poorer returns will only make the problem worse (Marsh, 2004). If we were to cut back on the harvest for a few years to try to make up for more returns in the future, the depleted river system would still not be able to support the fish populations and many of the following year's fry would die.
Less obvious is the impact of poor salmon returns on the ecosystem of the Kenai River. It has been well documented that bears, birds, and other animals along the Kenai River and its tributaries depend on salmon for a portion of there life requirements (Bisgard et al. 2001). If management actions by ADF&G or natural events reduce the number of fish entering the system, there will not be enough nutrient cycling and carcasses available for food. This is an important biofeedback mechanism that should be considered in all management actions.
What We Can Do Locally
In our search to find solutions to the climate crisis, we first decided that people must be better educated. George Lakoff, who teaches linguistics at the University of California, Berkeley, argues that the words "global warming" makes people think that it is a good thing. When humans hear "warming", they feel pleasant emotions and tend not to react to the threat (Butler, 2004).
Because the population needs to comprehend that the global temperature crisis is a serious problem with dangerous consequences, cognitive scientist Lakoff suggests that we change the vocabulary to something that conveys the seriousness of the situation. Responding to this idea, we decided that the first step to take in informing the people about global warming would be to change the phrase into something more dire, such as "global temperature crisis", "Atmospheric Asphyxiation", or "climate crisis". We feel that by changing the recognized term to something that better demonstrates the gravity of the situation, people might begin to heed the warnings of scientists and understand the hazard our community may face (you will note we have not used the term global warming in this paper).
For our local community, we have prepared a public service announcement [WAV file, 1.5 MB] that changes the tone of this discussion (see Appendix B and attached disc). This public service announcement will be played on the local radio stations and, we hope, by others to raise public awareness. However, we realize that people also need information, and for that we have constructed a web page that is accessed through the Skyview High school web page. The theme for our web page is for people to take personal responsibility for their actions, which contribute to the global temperature crisis.
In response to the potential for a major decrease in salmon populations in the Kenai River system, our team decided that the community's economy must be stabilized, and alternatives found for those who may lose jobs to the decline in salmon-related industries. We are not able to incorporate the displaced fishermen unless we go against our community's values. We focused on the bed and breakfast industry during the fishing season as an indicator if indirect relations to the fishing industry.
The Kenai Peninsula is well known by tourists and residents for their extensive trail system. Some of the commonly traversed trails include Skyline Trail, Fuller Lakes Trail, Resurrection Trail, Seven Lakes Trail, Russian River Trail, and many others (Happy Trails, 2003). Along these trails, such activities as hiking, backpacking, camping, biking, skiing, wildlife and bird viewing, photography, and even picnicking, are encouraged. Winter activities include snowmobiling, cross country skiing, snow shoeing, dog mushing, and ice fishing.
Tourists coming to the Kenai Peninsula to follow these trail systems are presently a small part of our economy. One of the facets of our plan to help the Kenai Peninsula remain economically stable, despite a drop in the salmon populations, includes adding more trails. These trails will be advertised to their best advantage, and specific types of trails will be constructed to meet the needs of tourists. Better biking trails will be made for all bikers; backpacking trails will be connected statewide for avid adventurers. In this way, our community may make greater and more profitable use of one of our major assets: the wilderness. With more tourists and nature buffs coming to the Kenai Peninsula for these activities, bed and breakfasts, restaurants, and stores will continue to get business. This would also open the door to other forms of stores, such as outdoor outfitters.
Some members of our team previously started this concept for wetland areas near the Kenai River mouth in 2002 (Beatty et al. 2002). The effort focused on bird watching and the significant growth in that industry. We felt that the community should build on this and be more inclusive of other activities and interest.
Also, we looked at the health of local ecosystems, especially the small tributary systems that rely on salmon carcasses for nutrients. In Washington and Oregon, small streams that have few salmon returning have been seeded with salmon carcasses from other areas to provide essential nutrients and food for adjacent wildlife (Bilby et al., 1996). Our plan involves assessing which streams may meet the criteria for this activity and doing so with carcasses collected from other sections of the Kenai River system that has abundant carcasses. This would serve to feed adjacent wildlife and return marine nitrogen to the stream.
What We Can Do Internationally
Internationally, scientists agree that a global plan is needed to slow the climate crisis. They also agree that reducing emissions of carbon dioxide from burning fossil fuels is the first and most obvious step in slowing this process (Block et al., 1990). In 1997, delegates from one hundred and sixty countries met in Kyoto, Japan to prepare an agreement known as the Kyoto Protocol. Our team feels that the signing of agreements limiting the burning of fossil fuels, and the global use of alternate sources of energy, is essential to slowing these significant temperature increases in our environment.
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