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Our Precarious Earth and its Biosphere. Milton Saier Professor of Molecular Biology University of California, San Diego msaier@ucsd.edu. Population Reduction and Earth Preservation (PREP). honors. EARTH DAY -. EVERY DAY!. One people,. One biosphere,.
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Our Precarious Earth and its Biosphere Milton Saier Professor of Molecular Biology University of California, San Diego msaier@ucsd.edu
Population Reduction and Earth Preservation (PREP) honors EARTH DAY - EVERY DAY! One people, One biosphere, One Earth, One future. Visit: http://stuorg.ucsd.edu/~prep
Overpopulation • The world's population is now about 6.3 billion and it is still expanding very rapidly, despite a marginal slowing over the last couple of years. • Every day we share the Earth and its resources with 250,000 more people than the day before; every year, there are about another 90 million mouths to feed. • It is the equivalent of adding a Philadelphia to the world population every week; • a Los Angeles every two weeks; • a Mexico every year; • and a US and Canada every three years.
“Discovered” by the Dutch Explorer Jacob Roggeveen in 1722 • Barren grassland without a single tree or bush over 10 feet high. • Around 2000 inhabitants speaking language of Polynesian origin. • Only 47 species of plants (mostly grasses, sedges, and ferns). • Native animals included nothing larger than insects. Domestic animals, only chickens.
Around 300 statues erected along coast. • Heights of 33 feet. • Weighing up to 82 tons.
Around 700 more in various stages of completion. • The largest of these unfinished statues was 65 feet tall and 270 tons.
In the 1960s the Swiss writer Erich von Däniken claimed they were the work of extraterrestrial astronauts with ultramodern tools, who became stranded on Easter, and were finally rescued.
Archeology • Radio Carbon dates estimate first human arrival around 400 AD, also supported by linguistic research. • Garbage heaps have shown that early Easter Islanders subsisted on fish, seabirds, and a large quantity of dolphin.
One Mystery Solved • Palm furnished canoes to hunt dolphin. • Palm also provided rollers to move statues from quarries to coast. • Ropes from the huahua tree enabled islanders to erect massive statues. • Toromiro tree yielded firewood to cook fish, seabirds, and dolphin.
Population • Densities of archeological sites suggest a large population. • Archeologists put the population at between 7,000 and 20,000 at Easter’s height, around 1,400AD. • Plenty of people to carve, transport and erect the statues.
But where did the trees go? • Pollen analysis shows palm population declining by 800 AD. • Just after 1400 AD, the last of the palm trees had disappeared. • What happened to the trees? • Forests were cleared to plant gardens, build canoes, and to transport and erect statues. • Native birds responsible for pollinating trees’ flowers and dispersing their fruit had died out.
Disastrous Effects on Food Sources • No more canoes to hunt dolphin or fish. • Dolphin bones disappeared abruptly from garbage heaps around 1500 AD. • Soil erosion ruined crops and gave no hope for the forests return. • Land birds, large sea snails, and many seabirds disappeared.
Warfare and Cannibalism • Rival clans began to fight for the dwindling resources. • Spear points littered the landscape. • Statues were pulled down by warring factions. • People took to living in caves for protection against their enemies. • As resources dwindled, people turned to the only sources of protein left. • First rat bones and then human bones began to make up a larger portion of bones in the garbage heaps.
Population Crash • 1400 AD: Population at its height, estimated between 7,000 and 20,000 individuals. • 1700 AD: Population crashed to between one-quarter to one-tenths of its former numbers. • 1900 AD: Population was 111.
Chaco Canyon’s pueblo was the largest structure ever built in North America until the Nineteenth Century’s skyscrapers. • 650 rooms • 5 stories high • 670 feet long • 315 feet wide
Archeologists have established that construction of the pueblos began around 900AD and occupation ended in the Twelfth Century. Why build a city in the desert? Where did they get the material, especially the 200,000 16-foot-long beams to support the roofs? Why did they abandon the city after putting so much work into building it?
From Forest to Desert • The damaged ecosystem was no longer able to support a large number of crops. • While natural climate change in the form of a drought was once thought to have been the sole reason for the abandonment of Chaco Canyon it is now clear that the extreme damage to the resource base was also a major contributor.
Middle East • Birth place of our civilization. • Agriculture, animal domestication, and writing developed here. • This area of the world was called the Fertile Crescent, implying an area of abundance. • The Middle East and Mediterranean was once a lush mosaic of wooded hills and fertile valleys.
So what happened to the Fertile Crescent? • Thousands of years of deforestation, overgrazing, and erosion have transformed this Garden of Eden into a dry, desolate expanse. • This theory of environmental destruction is supported by contemporary accounts and archaeological evidence.
Petra • Made famous (in the US) by Indiana Jones and the Last Crusade. • Once a thriving commercial center which controlled trade between Europe, Arabia, and the Orient. • Now ruins among the sand.
The Shift of Power • After the Mideast had overexploited its environment, power moved to Greece, then Rome, then to western and northern Europe. • Today the US, Europe and parts of Asia are the top resource-users, but we are not just exploiting the resources of our own area.
World Economy and Globalization • With the advent of modern international trade and shipping we are no longer limited to using just those resources we have at hand. • Our population keeps increasing at a tremendous rate and so does our consumption of resources. • We are now capable of literally creating an economic and societal collapse of the entire World similar to Easter Island.
Global Warming 1. We add 6 billion tons of CO2 to the atmosphere every year. 2. Only 1% of this CO2 can be recycled by the entire photosynthetic capacity of the Earth. 3. Most methane production is due to man-related activities. 4. Atmospheric temperatures, previously constant for over a century, are measurably higher than in 1980. 5. There has been no increase in solar yield. 6. Human activities are responsible for this global warming.
Our Temperature Buffer 1. Glacier National Park: 1900: 150 glaciers 2000: 35 glaciers 2030: 0 glaciers 2. Worldwide, we are losing our ice caps and glaciers. 3. Their loss is clearly related to human activities. 4. When they are gone, atmospheric temperatures will skyrocket.
Consequences of Global Warming 1. Elevated atmospheric temperatures 2. Loss of glaciers, ice caps and their ecosystems 3. Increased ocean levels, decreased land surface 4. Altered flora and fauna; species extinction 5. Increased drought, evaporation and humidity 6. Loss of our current agricultural land 7. Facilitation of disease transmission
Drug Resistant Pathogens 1. Drug resistance in bacteria is becoming a major human health problem. 2. Some enterococci and staphylococci are resistant to all known antibiotics. 3. Many human diseases are re-emerging with increased virulence. 4. New human diseases are arising, probably by jumping from other animals.
HIV: A New Human Disease 1. HIV probably “hopped” to humans from another primate. 2. Billions of dollars have been spent on HIV. 3. HIV is currently the best-understood virus. 4. We still have no cure. 5. We still have no vaccine. 6. Treatment is costly with severe side effects.
The Oceans The water is still there! But: 1. the level of pollution is significantly increased. 2. the fish populations are reduced, often to <1% of normal. 3. thousands of species are already extinct. 4. One-third of coral reefs worldwide are dead, one-third are dying, and only one-third are still healthy. 5. Few of the causative agents of coral diseases have been identified, so we have no cure.
Marine Statistics: San Diego Sea Life
Large Fish off the San Diego Coast 1. Before 1920, large sea bass, cow cod and groupers over 6 feet in length were caught off the San Diego coast. 2. None has been seen in the area for at least 20 years. 3. Cow cod are down to 1% of their original population world wide.
Cow cod, extremely long-lived fish now perhaps at 1% of their old level
Green Turtles in San Diego 1. In 1920, San Diego was a canning center for turtle soup. 2. Huge Green turtles were numerous in the San Diego Bay and nearby coastal areas. 3. After depleting the supply, the canneries went out of business. 4. No one has seen a full sized green turtle in the area for several decades.
California Lobster 1. Large Californian Lobsters were still plentiful in San Diego in the early 20th century. 2. They were caught for their tails, which were canned. 3. The San Diego Historical Society photographed huge fields of lobster skeletons, piled up to three feet deep. 4. Today, a lobster is caught on the average about eight times before it is legally large enough to keep. 5. The largest specimen found today are only a quarter of their mature size.
Abalone in San Diego 1. In the early 1950s, the ocean was covered with abalone. 2. A competent commercial diver could get two tons of abalone in a single dive. 3. Five species were prevalent: white, red, pink, green, and black abalone. 4. Today only the reds are left, and their population has been reduced to about 5% of its original size. 5. No one has seen a white abalone for years, and the blacks and greens are in serious trouble.
