Human Impact on the Biosphere Chapter 50. Pollutants are substances with which ecosystems have no prior evolutionary experience and therefore cannot deal with them. Carbon oxides CO, CO 2 Sulfur oxides SO 2 , SO 3 Nitrogen oxides NO, NO 2 , N 2 O
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Each day 700,000 metric tons of pollutants are dumped into the atmosphere in the US alone
Thermal Inversions are when weather conditions trap a layer of cool, dense air under a layer of warm air. Thermal inversions can trap pollutants close to the ground
Normal air circulation pattern
warm inversion air
Air pollutants trapped under a thermal inversion layer
Major coal-burning power and industrial plants
Ultrafine particles reach alveoli in lungs and contribute to respiratory disorders. High concentrations can cause lung cancer.
metallurgical dust, fumes
Average particle diameter (µm)
Why is the loss of the Ozone Scary?
Lowest ozone values are in magenta and purple.
In NATURAL ecosystems, one organism’s waste serves as resources for others.
Converting Marginal Lands for Agriculture
- Almost 21% of land is used for Agriculture; another 28% is available but may not be worth the cost
- the green revolution has increased crop yields but uses many times more energy and mineral resources
- a growing human population is moving into marginal lands to meet our increasing needs
ice, snow, deserts, mountains
At one time tropical forest cloaked regions that were collectively 2X the size of Europe and home of 50-90% of all land dwelling species.
In 4 decades humans have destroyed more than half of the forests and most of the species.
Each year another 34 million acres is logged over = to leveling 34 city blocks every minute.
Deforestation- the removal of all trees from large tracts of land for logging agriculture and grazing.
In Shifting cultivation (slash-and-burn agriculture) trees are cut, the land used for a few growing seasons and then abandoned as fertility plummets.
Desertification is the conversion of grasslands and croplands to desert-like conditions
Fossil Fuels are limited resources, extraction costs are increasing and atmospheric levels of carbon, nitrogen and sulfur oxides are also increasing.
Hydropower, geothermal, solar 7%
Nuclear power 5%
Hydropower, geothermal, solar 6%
Nuclear power 1%
Natural gas 25%
Natural gas 7%
Nuclear fuel burned for 10 days right through a 6-foot thick steel and gravel barrier
Distribution of radioactive fallout within 2 weeks of the meltdown - Reached Europe
Made crops & live stock unfit for consumption
After soviet union's breakup, some underpaid workers of a Russian nuclear power plant have been selling fuel elements on the black market.
Developing nations that want to produce nuclear weapons - possibly deliver them to the hand of terrorist organization
In 1995 - these cells generated almost 4 million kwatt hours of net electricity in the US
“ If we make the transition to an energy-efficient solar-hydrogen age, we can say good-bye to smog, oil spills, acid rain, and nuclear energy, and perhaps to global warming. The reason is simple. As Hydrogen burns in air, it reacts with oxygen gas to produce water vapor – not a bad thing to have coming out of tailpipes, chimneys, and smokestacks.”
-G. Tyler Miller, Jr. (Environmental Scientist)