Carbon Dioxide

D. L. Lindstrom of the University of Illinois at Chicago and D. R. MacAyeal of the University of Chicago examined records of cores of ancient ice from Siberia, Scandinavia, and the Arctic Ocean. Using computers to simulate the status of ice and atmosphere going back 30,000 years, they found the earth's temperature had increased as the levels of carbon dioxide had increased. At the end of the most recent ice age, the rise in temperature was sufficient to melt the ice. Their findings suggest that cycles of ice ages followed by shorter warm periods may have been caused solely by rising and falling levels of carbon dioxide.

In 1986, worldwide carbon dioxide emissions from transportation and industrial sources totaled somewhat less than 5 billion tons, but in 1987, the total rose to more than 5.5 billion tons and has continued to rise through the early 2000s. The burning of fossil fuels and deforestation has two significant effects on carbon dioxide content of the air: (1) it eliminates the photosynthesizing organisms that remove carbon dioxide from the atmosphere, and (2) it results in carbon stored in wood and other biological molecules being released into the air as carbon dioxide. Burning of fossil fuels and deforestation have been largely responsible for a 25% increase of carbon dioxide in the atmosphere since 1850. In the last 25 years alone, the earth's atmosphere has become 0.4°C (0.7°F) warmer, and between 1983 and 1990, the surface temperature of the ocean rose about 0.8°C (1.5°F).

Those may not seem to be significant amounts, but during the last ice age in North America when ice covered the northern United States and Canada, the average temperature of the earth at sea level was only 4°C (7°F) colder than it is now. In 1989, Mostafa Tolba, head of the United Nations Environment Program, estimated that if current levels of gas released into the atmosphere continue, the earth's temperature is likely to rise between 1.4°C and 4.3°C (2.5°F and 8°F) by 2039.

Higher temperatures melt ice at the poles and after melting cause water to expand. Higher ocean levels cause inundation of low-lying, often densely populated, coastal areas. The Environmental Protection Agency estimates that for each 30 centimeters (11.8 inches) the sea rises, it encroaches 30 meters (100 feet) inland, and already during the past century, worldwide ocean levels have risen 12.7 centimeters (5 inches). It is estimated that 7,000 square miles of land in the United States alone will be flooded if the temperatures rise as predicted. Major shifts in population to higher latitudes could follow, with the grain belts of the midwestern United States shifting into Ontario, and the fertile crescents of Asia shifting north into Russia. Higher temperatures can also have major effects on winds, currents, and weather patterns, causing droughts and creating deserts in some areas, while bringing about heavy rainfall in others.

Stern-Jansky-Bidlack: 25. Ecology Text © The McGraw-Hill

Introductory Plant Biology, Companies, 2003

Ninth Edition

Stern-Jansky-Bidlack: 25. Ecology Text © The McGraw-Hill

Introductory Plant Biology, Companies, 2003

Ninth Edition

w arene s s

John Muir, Fath er of America's National Park System

Today, America's national parks are overcrowded as some 270 million people enjoy their beauty each year, relaxing in the great outdoors, hiking in fields and mountains, or navigating their rivers. Whether it is Yosemite, the Grand Canyon, Acadia, or one of the many others, each park has a unique and special appeal. These magnificent parks are the result of many people's vision and foresight; however, perhaps none more so than John Muir who lived from 1838 to 1914. Often called the "Father of the National Park System," he influenced presidents, members of Congress, and "just plain folks" by his love of nature and his writings about it. Always traveling and exploring various ecosystems, he visited Alaska five times, walked 1,000 miles from Indianapolis to the Gulf of Mexico, as well as walking across California's San Joaquin Valley to explore the Sierra Nevada. Later he wrote of viewing the Sierra Nevada range for the first time, "Then it seemed to me the Sierra should be called not the Nevada, or 'Snowy Range,' but the Range of Light, the most divinely beautiful of all the mountain chains I have ever seen."

Wherever he roamed in the wilderness, he noticed increasing waste and destruction from various sources, whether overgrazing by cattle and sheep or overcutting by loggers. It was his love for the American forest that drove him to work tirelessly for its preservation. He wrote some 300 articles and 10 books that told of his travels and contained his naturalist philosophy. He called to everyone to "climb the mountains and get their good tidings." He wrote that the wilderness should be preserved, viewed as a treasure rather than a resource to be exploited. Through his writing, he drew attention to the destruction forests were facing and worked to find remedies.

One solution was the formation of national parks. Largely through Muir's efforts, Congress, in 1890, created Yosemite National Park. He was also personally involved in the creation of Sequoia, Grand Canyon, Mount Rainer, and Petrified Forest national parks. He went one step further by founding the Sierra Club in 1892 and served as its first president until his death in 1914. He and his friends conceived the Sierra Club with the mission to "do something for wilderness and make the mountains glad." His idea was to form an association that would work to protect Yosemite National Park.

This brought him to the attention of President Theodore Roosevelt, who visited Muir in Yosemite in 1903. Together with Muir, under the trees of the park, Roosevelt's innovative conservation programs began to take form.

John Muir's words and life inspire environmental activism today; they also teach the importance of enjoying nature and protecting it. Muir wrote a warning that is just as timely today as it was 100 years ago.

Plant Carbon Dioxide Light

Shafts of light penetrate the coastal

Box Figure 25.1

redwoods of Muir Woods.

Shafts of light penetrate the coastal

The axe and saw are insanely busy, chips are flying thick as snowflakes and every summer thousands of acres of priceless forests, with their underbrush, soil, springs, climate, scenery and religion, are vanishing away in clouds of smoke, while, except in the national parks, not one forest guard is employed. Any fool can destroy trees. They cannot run away; and if they could, they would still be destroyed—chased and hunted down as long as fun or a dollar could be got out of their bark hides, branching horns or magnificent bole backbones. Few that fell trees plant them; or would planting avail much towards getting back anything like the noble primeval forest.1 A living memorial to John Muir is located 12 miles north of San Francisco, Muir's home in his later years. Muir Woods is a 560-acre national monument consisting of

1. Atlantic Monthly, No. 80, 189T.

504 Chapter 25

Awareness Box Continued a grove of majestic coastal redwoods along a canyon floor. The towering redwoods and lush canyon ferns growing along Redwood Creek make this a forest of tranquility. Only a 30-minute drive from San Francisco, Muir Woods is visited by over 1.5 million people each year. He declared that this grove of coastal redwoods was the "best tree-lovers monument that could possibly be found in all the forests of the world."

John Muir—lover of America's forests, roamer of the wilderness, inspired writer, and fighter for conservation.

D. C. Scheirer

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