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Human Population: Atmospheric Science
Transcript of Human Population: Atmospheric Science
RESPONDING TO CLIMATE CHANGE
FUTURE TRENDS AND IMPACTS
GLOBAL CLIMATE CHANGE
Social and Economic factors affect Biodiversity:
Early European immigrants and their descendants viewed Costa Rica’s forests as an obstacle to agricultural and timber development.
Since 1945, Costa Rica’s population quadrupled and pressures on land increased.
Beginning in 1970, Costa Rica began protecting its land resources. Today over a quarter of the country’s area lies within national parks or other protected reserves.
Tourists now visit Costa Rica for ecotourism.
Hypothesis: Hot, dry climate conditions caused increased adult mortality and breeding problems among golden toads and other amphibians.
Evidence: Review of climate records revealed an increasing number of dry days from 1973 to 1998. Other observations note changes in the community from moisture-dependent species to more dry-tolerant species.
Climate Change, Disease, and the Amphibians of Costa Rica:
Local residents in Costa Rica’s mountainous Monteverde region told of an elusive golden toad that appeared only in the early rainy reason.
In 1964, Dr. Jay M. Savage and his colleagues encountered hundreds of these golden toads, which had never been formally discovered, during an expedition.
The newly discovered species went extinct 25 years later when global climate change caused drying of the forest.
Because all amphibians breathe and absorb water through their skin at some stage of their life, they are sensitive and vulnerable to individual or a combination of external environmental stressors.
Of the tigers that still survive in small pockets of their former range, those in the subspecies known as the Siberian tiger are the largest cats in the world.
For thousands of years, the Siberian tiger coexisted with the native people of what is today the Russian Far East, who equated the tiger with royalty and viewed it as a guardian.
The Russians who moved into and exerted control over the region in the early 20th century had no cultural traditions that expressed respect for the animal, causing the species to decline to as few as 30 animals.
Today, the population is in a range of 430 to 500 tigers, and 1,500 more survive in zoos around the world.
Saving the Siberian Tiger
One advantage of single-species conservation is in highlighting public awareness, especially if the organism in question is charismatic megafauna, such as a lion, tiger, or bear.
Typically, it’s the large mammals or birds, not the less charismatic vertebrates, invertebrates, or plants that are the focus of single-species conservation. Whereas, preserving and conserving habitats protects species that have yet to be discovered/studied and may be more economically feasible in the long term.
Single-Species Conservation: Pros and Cons
The lithosphere is everything that is solid earth beneath our feet.
The atmosphere is comprised of the air surrounding our planet.
The hydrosphere encompasses all water in surface bodies, underground, and in the atmosphere.
The biosphere consists of all the planet’s living organisms, or biotic components, and the abiotic portions of the environment with which they interact.
The number of dead zones has been rising globally.
Environmental scientists (Thomas Malthus and Paul/Annie Ehrlich) believe that there are limits to human population growth.
Even if resource substitution could enable indefinite population growth, could we maintain the quality of life that we would desire?
Population is one of several factors that affect the environment.
The IPATS model represents how humans’ total impact (I) results from the interaction among four factors—population (P), affluence (A), technology (T), sensitive a given environment is to human pressures(S): I = P × A × T× S.
Modern-day China shows how all elements of the IPATS formula can combine to result in tremendous environmental impact in very little time.
Impact can generally be boiled down to either pollution or resource consumption.
Earth has a carrying capacity for us.
Estimates of carrying capacity range from 1–2 billion people living prosperously in a healthy environment, to 33 billion living in extreme poverty in a degraded world of intensive cultivation without natural areas.
The naturally occurring sex ratio in human populations at birth features a slight preponderance of males. A greatly distorted sex ratio can lead to problems. In China, selective abortion of female fetuses has skewed the natural sex ratio.
Birth control is a key approach for controlling population growth. Birth control limits the number of children one bears, by reducing the frequency of pregnancy.
Family planning is the effort to plan the number and spacing of one’s children, so as to assure children and parents the best quality of life possible.
STUDYING CLIMATE CHANGE
we study the atmosphere to understand how pollution affects climate, ecosystems, and human health.
In addition, we try to protect our food resources, and predict violent storms that will harm people.
The atmosphere is a thin layer of gases that surrounds Earth.
Over our planet’s long history, the atmosphere’s composition has changed.
The atmosphere is layered.
The bottommost layer is the troposphere, which blanket’s Earth surface and gives us the air we need to live.
The stratosphere extends from 11-50 km above sea level. Between 17 km and 30 km it is called the ozone layer.
This layer greatly reduces the amount of UV radiation that reaches Earth’s surface. The protection of the ozone layer is vital for life on Earth.
Weather specifies atmospheric conditions over short time periods, typically hours or days, and within relatively small geographic areas.
Hurricanes form where warm moisture-laden air over tropical oceans is rising.
Tornadoes form when a mass of warm air meets a mass of cold air and the warm air rises quickly, setting a powerful convective current in motion.
Temperature inversion is a layer of cool air beneath a layer of warmer air.
This is a type of weather event that causes environmental health.
Inversions trap pollutants in cities surrounded by mountains.
Climate describes the pattern of atmospheric conditions found across large geographic regions over long periods of time.
One pattern is the latitudinal distribution of moisture across Earth’s surface.
a). Near the equator, solar radiation causes air to rise and creates a belt of precipitation
b). Another belt of precipitation occur around 60° latitude north and south
c). Sinking air around 30° latitude and in the polar regions, cause dry belts around the Earth.
Volcanic eruptions release large quantities of particulate matter and sulfur dioxide. Particulates reflect sunlight back to space and cool the atmosphere.
Fires also pollute. Human influence (fire suppression, development in fire-prone areas, “slash-and-burn” agriculture) make fires worse.
Winds can send huge amounts of dust aloft. Our unsustainable farming and grazing practices increase erosion/desertification.
immune system problems
in people and other organisms.
point sources (specific locations like a factory or power plant)
non-point sources (widespread sources such as cars)
Pollutants differ in the amount of time they spend in the atmosphere—
called their residence time
—because substances differ in how quickly they settle to the ground
Air pollution can emanate from:
Chinese cities suffer the worst air pollution and have created the Asian Brown Cloud, a 2-mile-thick layer of pollution over southern Asia.
Industrializing nations are suffering increasing air pollution because governments emphasize economic growth, not pollution control.
Photochemical smog, or brown-air smog, is formed when sunlight causes primary pollutants to react with our atmosphere gases.
Tropospheric ozone is the most abundant.
Smog is our most common air quality problem.
Since the onset of the industrial revolution, cities have suffered a type of smog we call industrial smog, or gray-air smog.
This forms when coal is burned and sulfuric acid is released.
Ozone molecules are considered a pollutant in the troposphere,
but in the stratosphere they are highly effective at absorbing incoming ultraviolet radiation from the sun,
thus protecting life on Earth’s surface.
Chlorofluorocarbons (CFCs) were produced at a rate of a million tons per year in the early 1970s. They were manufactured for air coolants, compressed gasses, and foam.
UV radiation breaks CFCs into chlorine and carbon atoms, the chlorine atom splits ozone.
CFCs can remain in the stratosphere for a century or more.
Human-made chemicals destroy stratospheric ozone.
In 1985, researchers discovered that stratospheric ozone levels over Antarctica in springtime had declined by half in just the previous decade.
In 1987 the Montreal Protocol was signed by 196 nations. It is considered our biggest environmental success story.
As a result, we have stopped the Antarctic ozone hole from growing worse.
However, the ozone layer is not expected to recover completely until 2060–2075.
Acid deposition involves acid-forming pollutants that fall onto Earth’s surface.
Burning fossil fuels releases sulfur dioxide and nitrogen oxides which react with water and oxygen to form sulfuric and nitric acids.
Acid deposition can release toxic metals which are stored in the soil.
This directly affects plants and our crops.
Acid water running off the land is toxic to many aquatic and terrestrial life forms and has led to the death of ecosystems.
The EPA focuses on seven pollutants which pose especially great threats to human health.
The Clean Air Act of 1990 strengthen regulations pertaining to air quality standards, auto emissions, toxic air pollution, acidic deposition, and ozone depletion.
New technologies such as cleaner burning engines, catalytic converters and scrubbers helped to reduce pollutants.
Scrubbers chemically remove pollutants before they leave the smokestacks of factories.
The average U.S. citizen spends 90% of the time indoors.
Indoor air generally contains higher concentrations of pollutants than does outdoor air.
As a result, the health effects from indoor air pollution in workplaces, schools, and homes outweigh those from outdoor air pollution.
Indoor air pollution in the developing world arises from burning wood with little to no ventilation.
Use of less-polluting fuels (natural gas), with better ventilation, will increase health dramatically.
Tobacco smoke and radon are the most dangerous indoor pollutants in developed nations.
limiting our use of plastics & treated wood
limiting our exposure to pesticides & cleaning fluids
monitoring air quality
keeping rooms clean
providing adequate ventilation
Global climate change describes trends in Earth’s climate, involving aspects such as temperature, precipitation, and storm frequency and intensity.
Climate change is the fastest-developing area of environmental science.
and cycles in the ways our planet spins, tilts, and moves through space,
influence how climate varies over long periods of time.
The current rapid climatic changes are due to the human activities of fossil fuel combustion and deforestation.
Greenhouse gases warm the atmosphere in a phenomenon known as the greenhouse effect.
As Earth’s surface absorbs solar radiation, the surface increases in temperature and emits infrared radiation.
Some atmospheric gases absorb infrared radiation effectively and are known as greenhouse gases.
Although carbon dioxide is not the most potent greenhouse gas on a per-molecule basis, its abundance in the atmosphere means that it contributes
more to the greenhouse effect than other gases.
Fossil fuel use is the main reason atmospheric carbon dioxide concentrations have increased so dramatically.
Deforestation reduces the biosphere’s ability to remove carbon dioxide from the atmosphere.
Other greenhouse gases are increasing in the atmosphere.
We release methane into the atmosphere by tapping into fossil fuel deposits,
raising large herds of cattle, disposing of organic matter in landfills,
and growing certain types of crops, including rice.
Nitrous oxide is a by-product of feedlots,
chemical manufacturing plants, auto emissions, and synthetic nitrogen fertilizers.
The oceans absorb carbon dioxide directly from the atmosphere, and hold 50 times more carbon than the atmosphere.
Warmer oceans absorb less CO2, which results in a positive feedback effect that accelerates warming.
Ocean water exchanges tremendous amounts of heat with the atmosphere. Ocean currents move energy from place to place. Greenland’s melting ice sheet will affect this flow.
Charles Keeling documented atmospheric carbon dioxide concentrations starting in 1958, and it has increased from around 315 ppm to 389 ppm.
Ice caps/glaciers have preserved tiny bubbles of ancient atmosphere.
greenhouse gas concentrations
frequency of fires
Evidence from paleoclimate - climate in the geological past.
Ice cores let us go back in time 800,000 year and eight glacial cycles.
The most thoroughly reviewed and widely accepted scientific information concerning climate change are reports issued by the Intergovernmental Panel on Climate Change (IPCC).
One reason warming is accelerating in the Arctic is that as snow and ice melt, darker, less-reflective surfaces are exposed, and Earth’s albedo, or capacity to reflect light, decreases.
Polar regions will continue to experience the most intense warming.
As glaciers and ice sheets melt, increased runoff into the oceans causes sea levels to rise.
If sea levels rise as predicted, hundreds of millions of people will be displaced or will need to invest in costly efforts to protect against high tides and storm surges.
Over one-sixth of the world’s people live in regions that depend on mountain melt water.
Some areas will receive more rainfall and others will receive less. Drought and floods would result.
Increased CO2 is acidifying the ocean and organisms can’t build their exoskeletons.
Changes in timing of seasonal events such as the onset of spring are creating complex effects in ecosystems worldwide.
Organisms are adapted to their environment and are affected when the environment is altered.
Agriculture—cuts in agricultural productivity are possible as droughts and floods increase.
Forestry—insects, disease outbreaks, invasive species, and catastrophic fires could all become more common.
Health—humans will experience more heat stress, tropical diseases, respiratory ailments, and hunger when droughts occur, and compromised sanitation during floods.
Economics—global climate change will cost nations.
Climate change affects people.
One strategy is called mitigation which hopes to lessen the severity of climate change.
The second strategy is called adaptation because the goal is to adapt to change by finding ways to cushion oneself from its blows.
We can respond to climate change in two fundamental ways.
Electricity generation is the largest source of U.S. CO2 emissions.
Conservation and efficiency can arise from energy-efficient technologies, or from individual ethical lifestyle choices.
The EPA’s Energy Star Program rates appliances, lights, windows, insulation, heating and cooling systems by their energy efficiency. Replace old appliances with efficient ones.
Use compact fluorescent lights and LED lights.
Natural gas has less impact on global warming than oil or coal.
We can also reduce greenhouse gas emissions by switching to clean renewable energy sources.
70% of electricity comes from fossil fuels, of which coal is the most commonly burned.
Transportation is the second largest source of U.S. greenhouse gases.
Increasing public transportation options is the single most effective strategy for conserving energy and reducing pollution.
Choosing where to live to reduce travel distance to work and school will save energy.
In 1992, the Kyoto Protocol international treaty required all 127 signatory nations to reduce greenhouse gas emissions to levels below those of 1990.
The U.S. Senate has steadfastly opposed emissions reductions out of fear that they will dampen the U.S. economy.
Just as we each have an ecological footprint, we each have a carbon footprint that expresses the amount of carbon we are responsible for emitting.
Hubbard Research Forest was established in New Hampshire in 1955.
the pH of the Hubbard Brook precipitation was found to be several hundred times more acidic than natural rainwater.
It was hypothesized that the fossil-fuel burning plants of the Midwest provided the compounds that increased the acidity of the soil in the northeast United States. The Clean Air Act of 1970 was amended in 1990 to restrict acidic compounds from these Midwest factories and power plants.
In 1996, researchers found that acidic deposition was leaching calcium and magnesium out of the soil. These nutrient deficiencies weakened trees making them more vulnerable to drought and insect damage.
Acid Rain at Hubbard Brook Research Forest
Rising Seas May Flood the Maldives
Timing Greenland’s Glaciers as They Race to the Sea
Nearly 80% of the Maldives’ land area lies less than 1 m (39 in.) above sea level, and the highest point of ground is only 2.4 m.
The world’s oceans rose 10–20 cm (4–8 in.) this past century and are expected to continue rising as temperatures warm, causing melting ice caps to discharge water into the ocean.
Higher seas are expected to flood large areas of the Maldives and cause salt water to contaminate drinking water supplies.
Scientists studying how ice moves were learning that ice sheets can collapse more quickly than expected and that Greenland’s ice loss is accelerating.
They also determined that the physical dynamics of ice flow accounted for two-thirds of total ice loss.
The IPCC report underestimated the likely speed and extent of future sea level rise.
Natural sources can pollute.
Toxic air pollutants are substances known to cause:
In addition, households’ burn lots of wood and charcoal,
and more people now own cars.
Keys to alleviating indoor air pollution:
Storm data suggest that warmer seas are likely to increase the power of storms and possibly their duration.
Warmer temperatures in the Arctic are causing permafrost (permanently frozen ground) to thaw.
Impacts of Climate Change upon different regions of the United States.
Many plants and animals shift toward the poles to avoid hotter and drier conditions.