Oct 6, 2005 (From the CalCars-News archive)
Summarizes global warming's impact in the Sierras -- and steps we can take.
http://syrcl.org/sierra-citizen/sc-view_article.asp?id=266 The Sierra Citizen, published by the South Yuba River Citizens League, "California's largest and most effective single-watershed organization" also reprinted in http://www.yubanet.com/artman/publish/article_26048.shtml YubaNet - Nevada City,CA,USA
Fall 2005 Issue
Hot Times in the Old Sierra Nevada
by Tim Omazu
Fires, pestilence, landslides, flooding. These days, such Old Testament-style calamities are likely to strike more often and with greater force in the Sierra Nevada, thanks to global warming.
By one prediction, California's average summer temperature may increase by nine degrees Fahrenheit over the next 100 years, even if the world slashes its output of global-warming gases-such as carbon dioxide-by 80 percent by 2050.
Such a reduction is a tall order. Roughly 20 pounds of carbon dioxide spews from every tailpipe of every car for every gallon of gasoline burned. That means 100 gallons of gas pump 2,000 pounds-one ton-of carbon dioxide into the atmosphere. It's statistics like this that give new meaning to the importance of fuel-efficient vehicles.
The worst news is that if we Americans (and the rest of the world, including oil-hungry developing nations) don't end our gas-guzzling ways and fail to hit that 80-percent reduction target, it is predicted that California's average annual summer temperature may increase 18 degrees Fahrenheit by this century's end.
If either scenario comes to pass, it would bring staggering changes.
Imagine summer being nine or 18 degrees hotter in the Central Valley or in Los Angeles. Nowadays, the average summer temperature in LA is 75 degrees. Bump that up to 84 or 93 degrees, and you're practically at Death Valley's average summer temperature of 95 to 100 degrees.
If that sounds alarmist, well ... global warming can make bad things happen. Case in point: Hurricane Katrina that devastated New Orleans and the Gulf Coast. A few months before the hurricane hit, MIT professor Kerry Emanuel published a paper in the journal Nature that said hurricanes have gotten bigger and badder over the last three decades-due, in part, to global warming. Emanuel has analyzed records of tropical cyclones-commonly called hurricanes or typhoons-since the middle of the 20th century. He found that both the duration of the cyclones and their wind speed have increased by about 50 percent over the past 50 years.
While global warming wouldn't cause hurricanes in the Sierra Nevada, it would still pack a wallop.
Sayonara Snowpack, Hello Mudpack?
For example, the Sierra's snowpack could recede thousands of feet uphill. Instead of snow, much more of the Sierra's precipitation-if the same amount continues to fall-would come in the form of rain. Currently, the snowpack melts slowly throughout the warm months, thereby providing half of the state's water storage. But if global warming causes the snowpack to shrink, reservoirs would have to be larger or managed differently, or the early deluge of rainwater would simply spill out.
Less snowmelt would also mean warmer water temperatures in the Sierra's rivers and streams, leading to reduced habitat for cold-water fish such as salmon and steelhead trout. Rivers would tend to run dry in the summer. And since rain hits the ground harder than snow, the result could be increased sediment to wash into the mountain range's waterways.
Don't count on a long skiing season, either.
Other changes that global warming could bring to the Sierra include a radical makeover in the type of forest cover, increased flooding and wildfires, and reduced capacity for the Sierra's fast-growing forests to act as a "sink" to hold carbon dioxide.
With a future that seems this cloudy, it's hard to find a silver lining.
But it's not too late to make changes that could mitigate global warming's impact, experts say.
"The important thing to realize ... is that [the temperature] rise really depends on our actions today," explains Amy Luers, a California-based climate-impact scientist with the Union of Concerned Scientists. "How bad it's going to get really depends on what we're doing now."
So how can we combat global warming? There are steps that professional resource managers and watershed groups can take. The rest of us can do our part, too.
Resource Managers Must Grapple with Global Warming
The Sierra Nevada Alliance-60 groups dedicated to protecting and restoring the Sierra-has commissioned Janet Cohen, SYRCL's former executive director, to put together a report called the Sierra Climate Change Toolkit-Planning Ahead to Protect Sierra Natural Resources and Rural Communities.
Cohen's draft report emphasizes how important it is for resource managers and watershed groups to factor global warming's effects into their calculations.
For example, over the next 15 years, federal licenses for more than 100 dams in the Sierra will expire-including dams on the South Yuba River. Many of these licenses were granted when there wasn't much emphasis on environmental concerns. For example, only a dribble of water is required as the release from Spaulding Dam on the South Yuba.
Environmentalists such as Cohen see relicensing as a once-in-a-lifetime chance to improve the health of rivers. But global warming has to be taken into account, she adds.
"People have to realize that this is happening," Cohen says. "The snowpack [threat] is really serious. It's imperative that the people who are working on negotiating [relicensing] demand that climate-change impacts be taken into account in the studies leading up to re-licensing."
Maury Roos, California's state hydrologist, explains that for every annual temperature increase of one degree Celsius, the snowpack would recede an average of 500 feet in elevation.
Instead of global warming causing the state to be 9 to 18 degrees hotter, Roos cites more-conservative-but still frightening-temperature-increase figures. He points out that the Intergovernmental Panel on Climate Change (IPCC) predicts that if fossil-fuel use continues at present levels, California's annual temperature could increase 3 degrees Celsius-or 5 degrees Fahrenheit-by the end of the century.
Multiply that 3 degrees Celsius by 500 feet in elevation, and that means the snowpack would recede 1,500 feet uphill.
"Particularly in the Yuba River [watershed], the snowmelt would be quite a bit east," Roos explains. "So you'd get more water runoff. For the Yuba River, I'd say the major impact [is] whether the water would get too warm for cold-water fish."
Roos thinks that global warming has already made its presence known in the Sierra Nevada.
"I think we're beginning to see some changes," he says, with snowmelt between April and July appearing to be down.
"That seems to have dropped off. Not dramatically."
The Sierra isn't Middle Earth, and its trees aren't Ents-they can't get up and walk away as the temperatures rise.
Over time, trees and other vegetation could change radically in response to global warming. Just as the snowpack is likely to retreat uphill, so are the forests. Conifers from lower elevations would displace alpine and sub-alpine vegetation. Likewise, oaks and madrone would replace lower-elevation conifers. And what's now foothill scrub forest would turn into grasslands.
But before this migration takes place-provided global warming doesn't happen so quickly that vegetation can't adapt by migrating-pestilence is likely to strike.
Insects and pathogens, by virtue of their mobility and short reproduction times, can respond to climate change much more rapidly than tree populations. As a result, insects and diseases are prime candidates to cause some of the early impacts of climate change on forests. Increased fire and drought are likely to lead to the type of environment ripe for the invasion and spread of introduced species.
So foresters need to take global warming into account and think about whether the trees they plant now will be viable in 50 years' time.
Scientists are also studying how forests act-and can be used-as "carbon sinks" to pull carbon out of the atmosphere. One such study is getting underway in 22,000 acres of Tahoe National Forest near Downieville.
The Nature Conservancy and the U.S. Forest Service are collaborating on a carbon-monitoring project that will use high-tech equipment to see how much carbon is stored in the Sierra and in a redwood forest near Mendocino.
Scientists say that the mixed-conifer forests of the Sierra and California's coastal redwoods store more carbon per acre than any other forest type on the planet. Thanks to congenial soil and plentiful winter rain, trees grow quickly in the Sierra Nevada, as long as they're not starved for sunlight or otherwise hindered. It is not uncommon to see one-inch-thick growth rings on the stump of a tree that had grown in an ideal spot.
The carbon-monitoring project will use high-resolution satellite images and airborne light detection and radar (LIDAR) to quantify forest carbon and to see if there are any altitudinal shifts in vegetation due to global warming.
Floods ... Or Drought?
The prospect of more winter rainfall raises all kinds of questions for resource managers.
"It makes it really hard to run your reservoirs," says Christopher Field, director of the Carnegie Institution's Department of Global Ecology at Stanford University.
Increased rainfall might overflow storm and wastewater systems. It might cause erosion and mudslides. And what about the mine-tailings impoundments that dot the Gold Country-such as a tailings dam made of logs that washed out near Grass Valley during the '97 flood, contaminating a small reservoir with arsenic-laden tailings?
Levees will be under pressure more often. Will they soften up and lose strength? Will they have to be moved back from riverbeds to hold the extra flow?
It's an open question as to whether global warming would bring more precipitation to the Sierra. It might bring less.
Worldwide, warmer temperatures and melting ice caps and glaciers are projected to create more rain-but not in the west.
"The most recent round of models are showing western North American, in general, coming up a little bit drier," Field states.
And that's worrisome, because "California doesn't have enough water for the people that we have here now," he adds.
Cars, Clotheslines, and Compact Bulbs
But what can the rest of us do to combat global warming?
For one, we can drive more fuel-efficient cars. Fortunately, a whole new class of super-efficient hybrids may be in the works.
It is said that there are two cars for every Californian. So it comes as no surprise that, according to The Union of Concerned Scientists, transportation accounts for 49 percent of our state's carbon-dioxide emissions.
The popularity of hybrid cars is increasing. This year, Toyota expects to sell about 180,000 of its four-door Prius, which gets about 55 miles per gallon. This represents a jump from about 40,000 Priuses sold last year.
By 2012, Toyota plans to offer a hybrid version of all its models. And every American, Japanese, and German automaker plans to offer a hybrid version of all its models within the next two years, according to the "Hightower Lowdown," a newsletter edited by Texas populist Jim Hightower.
But the Prius and its ilk may be only the first generation of hybrids. Better fuel efficiency, by a factor of ten, may be available through plug-in hybrid electric vehicles (PHEVs). Instead of primarily using gasoline power, these PHEVs would have lithium-ion batteries like those in a laptop computer, allowing drivers to travel 60 miles before recharging. That's three times the average driver's commute, points out the "Hightower Lowdown." So most drivers wouldn't have to go near a gas station. Recharging would be a snap, because the car would simply be plugged into a standard, 110-volt wall socket.
One might think that plugging a car into a wall socket would only increase the use of electricity plants that use such "dirty" fuel as coal. But that's still better than gasoline-powered cars, says the non-profit group California Cars Initiative (CalCars).
According to the CalCars Web site, "On the national [half-coal electric] grid, electric vehicles are still far cleaner than gasoline vehicles. And it's easier to clean central power plants than millions of vehicles. And utilities are increasingly being mandated to increase their percentage of power from renewable sources."
For example, the state of Nevada has a law that mandates that by the year 2013, 15 percent of all the state's electricity must be generated from renewable sources, such as geothermal plants and wind turbines.
Since PHEVs mainly steer clear of gas stations, they get about 100 miles per gallon. But that mpg-of-gasoline figure shoots through the roof-to 500 mpg-if you use biofuel, such as gasohol. A mixture of about 85 percent grain alcohol and 15 percent gasoline, alcohol-based fuel can be made by distilling plant waste, such as cornstalks, sawdust, and tree trimmings.
Of course, super-hybrid cars may be a few years off. But the average person can take steps right now to reduce his or her production of greenhouse gases. Something as simple as using a clothesline instead of a clothes dryer could have a big impact-if everyone did so.
The average American family devotes five to six percent of its annual electric budget to the motor and heating coils inside its clothes dryer, writes global-warming expert Bill McKibben in an article titled "Warming the World to Dry Our Socks."
"If we all used clotheslines, we could save 30 million tons of coal a year, or shut down 15 nuclear power plants," McKibben's article states.
Yet clotheslines are banned by nearly all of California's 35,000 homeowners' associations, according to Project Laundry List, a nonprofit group that is committed to ending the "lunacy" of such rules and restrictions. The group helped the state of Florida pass a right-to-dry bill that trumped all such restrictions in that state. Project Laundry List's Web site encourages people to work for right-to-dry bills in their states.
According to the American Council for an Energy-Efficient Economy, lighting accounts for about 20 percent of all the electricity use in the United States. Incandescent light bulbs convert about 90 percent of the electricity they use into heat-and only 10 percent into light. By comparison, compact fluorescent bulbs are much more efficient, using one-quarter to one-third the amount of electricity, the group says.
"If every household replaced its most commonly used incandescent light bulbs with compact fluorescent light bulbs, electricity use for lighting could be cut in half," explains the organization's literature. "Doing so would lower our annual carbon dioxide emissions by about 125 billion pounds. This action alone could halt the growth in carbon dioxide emissions from the United States given recent growth rates."
"California is a trendsetter in many ways. Technology and other changes adopted by the state to reduce global-warming gas emissions could set an example that others follow," says Dan Cayan of the Climate Research Division of the Scripps Institution of Oceanography.
Many experts agree that an 80-percent reduction in global-warming gases, worldwide, will be necessary to slow global warming. But there's a wrinkle.
"Since worldwide energy demand is expected to increase, the first world-including the United States-will have to reduce its global-warming gas output by 95 percent," says Stanford's Field.
Nonetheless, "I think climate change is a set of hard problems, but it's not a set of impossible problems," he adds.
Field says that solutions fall into four board categories: conservation, improvements in efficiency, new technology, and carbon sequestration.
The latter is already in use on an industrial level in oil fields, where carbon dioxide is pumped down wells to make oil more liquid, he explains.
"We don't know very much about the technologies available to use at the end of this century," Field states. "There may be technologies that we can't even dream about. If you had asked people in 1900 how they would go about solving a major problem, such as the spread of a then-incurable disease, they wouldn't have the know-how."
In the meantime, "It seems to me that it's our responsibility to keep the whole from falling apart," Field says. "I find that most Americans really are deeply concerned about having a sustainable environment and doing the right thing."