Warmer Climate for Whatcom County

Helen Brandt, Ph.D., is a Whatcom county writer. She provides individual tutoring, assessment and parent consultation for K-8 students - helenbrandt@comcast.net.

City and county planners are busy preparing for an increasing population and the strains on infrastructure it creates. Scientists working for the National Forest Service and the National Park Service, as well as the National Oceanic and Atmospheric Administration are preparing for a different development. Significant changes are in store for the Pacific Northwest and Whatcom County as our climate warms.

A new report from the U.S. Climate Change Science Program released in June 2008 details what has happened thus far and what we can expect in the future. The report, “Adaptation Options for Climate-Sensitive Ecosystems and Resources,” details changes that have already occurred in our area within the last half-century, and suggests adaptations that are likely as we move into the 21st century.

The report analyzes changes in the Olympic National Forest and Mount Rainier National Park. These prototype forests are indicative of the changes we will see in our own Mt. Baker/Snoqualmie National Forest and Wild Sky Wilderness.

Temperature changes in the past century have been well documented There has been a 1.8 degree Fahrenheit (1.0 degree Celsius) increase in annual temperature since 1920. Most of the increase has occurred since 1950, mainly in the winters.

By the year 2000 the snow spring runoff was occurring one to four weeks earlier than it had occurred in 1948. Particularly at lower elevations, since 1950 there has been a 30 to 50 percent decrease in snowpack. Higher winter and spring temperatures may account for the trend toward decreasing snow water equivalent (SWE) in the Pacific Northwest.

There are 700 glaciers in the North Cascades, the largest concentration in the lower 48 states. During the dry months from June to September they release approximately 230 billion gallons of water. The water is used for irrigation, power generation, and for salmon. Water from the base of the Nooksack Glacier, high on Mt. Shuksan, begins the North Fork of the Nooksack River.

The fastest moving glaciers in the North Cascades are those on the flanks of Mt. Baker. In some areas they can move 200 feet per year because the slopes are so steep and the ice is so thick.

During the period from 1984 to 2006 the average thickness of the North Cascades glaciers decreased by more than 46 feet (14 meters). In those 20 years they lost between 20 to 40 percent of their thickness. Forty-seven glaciers are monitored and all are retreating significantly. Three have disappeared altogether. As of 1975 eight glaciers on Mount Baker were advancing. In the twenty years since 1984 they have retreated more than 1,115 feet (340 meters).

The U.S. Geological Survey has carefully studied the South Cascade Glacier near the Cascade crest. The glacier lies at the head of the South Fork of the Cascade River, which is a tributary of the Skagit River. During the 1956-1975 period its average volume decrease was –0.15 meter per year. But during the 1976-2003 period its average volume decrease was –1.00 meter per year. The rate of decrease appears to be accelerating.

Rapidly retreating glaciers near populated areas can create local events. Between 2001 and 2006 the Van Trump Glacier on Mt. Rainier produced four debris flows, filling the Nisqually River with sediment. It raised the riverbed at least six feet. In the future, floods will spread farther from the riverbanks because the riverbed is higher.

Within the lifetimes of children born today, temperatures in our area are expected to increase by 2.16 to 9.9 degrees F (1.2 to 5.5 degrees C). The greatest increases are expected to occur during the summer months. However, warming winter temperatures will also significantly affect our North Cascades mountains.

A recent research study to be published in the journal, Geophysical Research Letters, created complex mathematical simulations of how increased temperatures affect snowpack in western mountains. The high-resolution climate model simulations assume mean global warming of 7.2 degrees F (4 degrees C). A model simulation was used to estimate historically observed data and a high level agreement was found between the modeled estimates and the historical data.

Scientists quantify the discussion by calculating the total yearly runoff due to melting snow (snow-driven runoff). They then determine on what days one-fourth, one-half, and three-fourths of the runoff have occurred.

The models show earlier snow-driven runoff over the Northwest. And there are likely to be decreases in accumulated snow even at the highest elevations of the Cascades. The date when one-fourth of the snowmelt occurs (early spring) is projected to occur 70 or more days earlier during the latter third of this century. The greatest changes in the timing of snowmelt would occur at the 3,900 to 5,900 foot elevations (1,200 to 1,800 meters),

When snow melts earlier in the season or does not cover the ground, the uncovered ground absorbs more warmth from solar radiation than it would if there were snow cover. This tends to amplify the effect of surface warming and further increases melting.

The early snowmelt would lead to increased winter and spring flooding.

This warming climate will have numerous consequences. Lakes and streams will lose more water through evaporation during the summer months. And the water will become warmer than it is now. For fish that need plenty of cool water, these developments could be detrimental.

With the melt of snowpack occurring earlier in the spring, runoff will decrease during the warmer months in the lowlands. This can affect the amount of summer water available for irrigation and for other human needs. The need for conservation of water supplies will increase.

In rivers and streams, decreased summer flows of water will decrease the dilution of pollutants. Earlier water runoff from melting snow could necessitate additional water storage capacity in reservoirs and could affect hydroelectric power generation.

Tree species that have not been able to grow at higher elevations because of the short growing seasons and heavy snowpack will be able to grow successfully at higher elevations. Alpine meadows will be subject to invasions of native trees.

Subalpine fir is already invading the Paradise flower fields at Mt. Rainier National Park. During mild winters the fir is able to gain a foothold and form tree islands. The groups of trees are better able with withstand cold and snow than are isolated trees standing alone.

Plants may flower earlier. But if their pollinators do not also arrive earlier they will not be pollinated. Fruit and berry production could be affected. If insect larva hatch sooner, birds that arrive at their usual, later migration time, could find little to eat. Their nestlings would go hungry. On the other hand, if the usual predators are not on hand when hatching occurs, insect populations could expand.

Summer heat, drought and vehicle emissions can interact in multiple ways. Ozone formation increases as temperature increases. The combination of heat and vehicle emissions can have significant consequences for air quality in areas far from urban centers. Ozone is a greenhouse gas rivaling methane in significance. It has quadrupled in the northern hemisphere since 1880.

Most people can notice ozone at 0.01 ppm (parts per million) in air. If levels are at 0.1 to 1.0 ppm, people can experience headaches, burning eyes and respiratory irritation.

Ozone created from precursors in the industrial Puget Sound lowlands or from the Fraser River Valley in British Columbia can be carried on prevailing winds to the North Cascades, especially during hot summer days. And long distance transport can bring us ozone from Asia. What might this mean for our forests?

Ozone can reduce trees’ ability to grow. Ozone has been found to reduce productivity in eastern and southern forests by 5 to 10 percent.

A Cornell research study compared young cottonwood trees growing in New York City, with young trees of the same species in the rural Hudson River valley. The city trees at the end of three years had twice the biomass as those in the rural area. How could that be? Unfortunately for the rural area, ozone concentrations there were higher than in the Bronx. (So much for moving to live in an idyllic rural setting!)

Ozone enters plants through pores in the leaves. There it interferes with the reactions involved in photosynthesis and leaves the plants weakened and undersized.

High levels of both CO2 (carbon dioxide) and O3 (ozone) cause leaf pores to close. This means plants take up less of the carbon dioxide they need for photosynthesis, but also absorb less of the harmful ozone.

Many common Northwest native plants are sensitive to ozone, including lupine, huckleberry, vine maple, salal and serviceberry. Trees such as Western hemlock, Douglas fir and red alder also can show ozone damage. Ozone can cause some trees to drop their leaves or needles sooner. They are more susceptible to drought, insects and disease. Needless to say, trees in a weakened state are also more vulnerable to wildfire.

Because of its effects on people and ecosystems, scientists have been collecting data on ozone in our forests and urban centers. Background ozone levels in western Washington have been steadily rising (from 10 ppb in the 1880s to close to 40 ppb in 2000). Monitoring stations at Paradise on Mount Rainier have shown levels of ozone increasing between 1999 and 2003, often at levels higher than Seattle and its suburbs.

Environmental Protection Agency (EPA) data on July 24, 2004, showed concentrations at levels of 110 parts per billion (ppb) near Mount Rainier, and exceeded the EPA’s health guideline of 85 ppb. More recently ozone concentrations have not shown a trend up or down.

Based on modeling, passive ozone sampling and on aircraft measurements, ozone increases 1.3 ppb with each 100-meter increase in elevation. Consequently, high elevation regions (mountaintops) experience greater ozone concentrations than do lower elevations. One of the highest concentrations in the Puget Sound area was at 5,400 feet elevation. Mt. Baker, at 10,781 feet, could be prone to elevated ozone concentrations.

With a warming climate, storms and droughts are expected to be more intense and less predictable. When water runoff from melting snow occurs earlier in the year, summer soil moisture decreases. Low soil moisture can contribute to the frequency and intensity of fires.

Forest fires can impact our lakes, streams and air quality. Local wildfires can increase the amount of phosphorus and sediment entering lakes and watershed streams. Wood smoke contains carbon monoxide, formaldehyde, nitrogen oxides and particulates.

Lake Tahoe is a good example of what can happen to a lake when forest fires occur. A December 2002 research report reported data on an intense forest fire, which occurred near the Tahoe basin. Aircraft took samples downwind of the smoke plume. Phosphorus concentrations were 10 times those of normal air over the lake. The sample included fine and coarse particulate phosphate. The study concluded that atmospheric deposition of phosphorus and nitrogen to the lake could be significant during local forest fires.

After a forest fire the bare ground can erode and wash sediment into streams and lakes during heavy winter rains. This can increase the amounts of phosphorus and nitrogen in the water and make the water less clear.

Forests in our area are less prone to fire than are forests on the dry east side of the Cascade Range. But the smoke transported from the east side and from British Columbia forest fires can affect our forests.

What changes will we see in our own lives? Hazarding some guesses, more people will install rain barrels to save spring rains for use during the dry months. Green lawns in July will disappear. In many cases grass will be replaced by lettuce, chard, potatoes, zucchini, rhubarb and strawberries. Sunny fences will support grape vines. Tomatoes will ripen to full perfection. Southern ornamental plants that could not be grown here because of low winter temperatures will thrive. Our ski season will be shorter.

Craig MacConnell, WSU Extension, expects to see both positive and negative impacts for local agriculture. The important thing is to prepare and plan on ways to mitigate any negative effects for farmers.

Reducing pollutants entering the atmosphere will be a priority. Hence highway-driving speeds will hover around the most efficient levels, 55–60 mph. Low-mileage vehicles will become relics. Bus and train service will become more frequent and convenient as more people use them.

Housing costs will increase as more people try to move here to escape the heat, water shortages and air quality warnings in other regions. Farmland will increasingly be seen as valuable for sequestering carbon, a use that conflicts with conversion to housing developments. To allow summer cooling, houses and offices will have windows that open. Transoms above doors will reappear.

As drought and heat increase the costs of agricultural produce in the Southwest, local vegetable and fruit farms will serve a greater portion of our needs. Finally, with warm summer evenings, more of us may sit outside, go for a walk and enjoy the company of our neighbors. §

Adaptation Options for Climate-Sensitive Ecosystems and Resources

• http://www.climatescience.gov/Library/sap/sap4-4/final-report/default.htm

North Cascade Glacier Climate Project

• http://www.nichols.edu/departments/glacier

• http://www.nichols.edu/departments/glacier/intro.htm