CH 19 APES
Terms in this set (50)
change that occurs in the chemical, biological, and physical properties of the planet
global climate change
the changes in the climate of Earth-the average weather that occurs in an area over a period of years or decades
specifically refers to one aspect of climate change: the warming of the oceans, landmasses, and atmosphere of Earth.
examples of global change
rising sea levels, increased extraction of fossil fuels, increased contamination, altered biogeochemical cycles, decreased biodiversity, emerging infectious diseases, over harvesting/exploitation of plants and animals, global climate change
examples of global climate change
increased storm intensity, altered patterns of precipitation and temperature, altered patterns of ocean circulation, global warming
examples of global warming
the warming of the planet's land, air and water, increased heat waves, reduced cold spells
steps of the greenhouse effect
1. incoming solar radiation consists primarily of UV and visible light (or ultraviolet radiate band visible radiation)
2. some (1/3) uv light is absorbed by the ozone layer in the stratosphere, but the remaining uv and visible light, passes through the atmosphere)
2. solar radiation is absorbed by clouds and the surface of the planet. the clouds and the surface of the planet emit infrared radiation
3, much of the infrared radiation is absorbed by earth with the help of greenhouse gases (it can not easily pass through the atmosphere)
3. nevertheless, because the planet is not as hot as the sun, it emits of the rest its energy as infrared radiation (aka infrared light) back into space.
4. the rest of the infrared light goes back toward the surface of the earth, causing the surface to become even warmer. the greater the amount of greenhouse gases, the more infrared radiate is absorbed and emitted back toward earth.
the net flux of energy
zero-inputs = outputs
potential problems with the recent years with the steady state of our earth.
1. if incoming solar energy is greater than the sum of reflected solar energy and reedited infrared energy, the energy accumulates faster than it is dispersed and the planet becomes warmer.
2. if incoming solar energy is less than the sum of the two outputs, the planet becomes cooler
the gases in the atmosphere that absorb infrared radiation
the two most common gases in the atmosphere
what does NOT absorb greenhouse gases
what DOES absorb greenhouse gases
H2O-water, CO2-carbon dioxide, CH4-methane, N2O-nitrous oxide, O3-ozone, CFCs-chlorofluorocarbons(the only one which does not exist naturally)
positives of ozone
it filters out harmful ultraviolet radiation
negatives of ozone
1. ozone in the lower troposphere acts as a greenhouse gas and can cause increased warming of the earth
2. an air pollutant in the lower troposphere--> cause damage to plants and human respiratory system
greenhouse warming potential
estimates how much a molecule of any compound can contribute to global warming over a period of 100 years.
calculate by considering:
1. the amount of infrared energy that a given gas can absorb
2. how long a molecule of the gas can persist in the atmosphere
the greenhouse gases with the greatest global warming potential (in decreasing order)
2. nitrous oxide (N2O)
3. methane (CH4)
4. carbon dioxide (CO2)
5. water vapor (H2O)-<1
natural sources of greenhouse gases
volcanic eruptions, decomposition, digestion, denitrification, evaporation and evapotranspiration
add CO2 to atmosphere
when decomposition occurs under high-oxygen conditions, the dead organic matter is ultimately converted into carbon dioxide. usually occurs at the bottom of wetlands where plants and animals decompose and oxygen is low in supply
or when animals digest plant matter
nitrous oxide (N2O)
a natural components of the nitrogen cycle that is produced through the process of denitrification.
usually occurs in the low oxygen environments of wet soils and at the bottoms of wetlands, lakes and oceans.
in these conditions, nitrate is converted to nitrous oxide gas, which then enters the atmosphere as a powerful greenhouse gas
most abundant greenhouse gas in the atmosphere and the greatest natural contributor to global warming.
the burning of fossil fuels
when humans burn fossil fuels, we produce CO2 that goes in the atmosphere
black soot may reflect solar radiation under some conditions and may be responsible for greenhouse gases.
particulates tat fall on ice and snow in the higher latitudes absorb more of the sun's energy by lowering the albedo. as the snow and ice begin to melt, the particulates become more concentrated on the surface. the increased concentration raises the amount of solar radiation absorbed, which increases melting. this is an example of a positive feedback loop!
1. agricultural fields that are overirrigated, or those that are deliberately flooded create low-oxygen environments similar to wetlands and therefore can produce methane and nitrous oxide
2. synthetic fertilizers that naturally fix atmospheric nitrogen can create an excess of nitrates in the soil that are converted to nitrous oxide by the process of denitrification
3. raising livestock-livestock eat a lot of plants and rely on gut bacteria to digest the cellulose. gut bacteria live in low-oxygen conditions and produce methane as a by-product
living trees remove CO2, and decomposing trees add CO2 to the atmosphere
when trees are not replaced, they net destruction of vegetation leads to an increase in CO2
when landfills are not aerated properly, they create low oxygen environment, like wetlands, in cinch decomposition causes the production of methane as a by-product
the family of chemicals that serve as refrigerants used in air conditioners, freezers and refrigerators
major contributors of methane to atmosphere
livestock, landfills, the production of natural gas and petroleum products
the major contributors of nitrous oxide
agricultural soils that receives nitrogen from synthetic fertilizers, applications of manure as an organic fertilizer, and nitrogen-fixing crop
major contributors of CO2-carbon dioxide
94%-burning fossil fuels for energy
intergovernmental panel on climate change, a group of over 3000 scientists from around the world working together to assess climate change
tiny, marine organisms having harsh ells that resist decay after death. the shells have been building up in sediments for millions of years. When scientists identify the predominant species of forminifera in a layer of sediment, they can infer the likely temperature of the ocean at the time the layer of sediment was deposited
use of ice
during the process of compression, the ice captures small air bubbles. the bubbles contain tiny samples of the atmosphere that existed at the time the ice was formed. scientists have traveled to these frozen regions of the world to drill deep into the ice and extract long tubes of ice called ice cores
recent temperature increases
the surface temperature of the earth has increased roughly .8 degrees C (1.4 degrees F) over the past 120 years
ice formed during a period of warmer temperatures contains a higher percentage of heavy oxygen than ice formed during colder temperatures
possibilities for warming temperatures
1. increase in solar radiation
2. warming is caused by increased CO2 in addition to warming caused by natural fluctuations
positive feedback loop
higher temperature lead to fast decomposition--> decomposition--> faster decomposition boosts the rate at which CO2 is added to the atmosphere -->CO2--> higher levels of CO2 promote higher temperatures
as CO2 increases from anthropogenic sources--> arctic regions become substantially warmer and the frozen tundra begins to thaw--> as it thaws, the tundra develops areas of standing water with little oxygen available under the water as the thick organic layers of the tundra wing to decompose--> organic material experiences anaerobic decomposition--> decomposition produces methane, a stronger greenhouse gas-->more global warming
because CO2 is required for photosynthesis, increased plant growth increases uptake of CO2 from atmosphere--> decreases the amount of CO2 in atmosphere
over the next 70 years, the arctic is predicted to warm by an addition 4 degrees C-7 degree C (7 degree F-13 degree F)
usually, glaciers would partially melt during the spring and summer, then grow back to their full size during the winer. however, as summers become warmer, glaciers are melting faster than they can grow back in the winter, leaving some people without a reliable water source
1. melting of the permafrost causes overlying lakes to become smaller as the lake water drains deeper into the ground.
2. melting can also cause substantial problems with human-built structures that are anchored into the permafrost, including houses and oil pipelines.
3. melting permafrost can also mean that the massive amounts of organic matter contained in the tundra will begin to decompose. because this would occur in wet soils under low-oxygen, it would release substantial amounts of methane increasing the concentration of this potent greenhouse gas (positive feedback loop)
as water of the ocean becomes warmer, it expands
this could endanger coastal cities and low-lying island nations by making them more vulnerable to flooding
cause more air conditioning and cooling, cause damage to crops, more irrigation would up the prices of food.
increased: more crops, recharge aquifers, flooding, landslides, erosion
decreased: more difficulty to grow crops, and greater efforts to supply water
fewer colder days, were deaths due to freeing, decrease in risk of crop damage, make new areas available to agriculture, decrease energy needed to heat buildings, allow pest species to expand their range
thermohaline circulation changes-increased melting from greenland and the norther polar ice cap could dilute slaty ocean water causing much of europe to experience significantly colder temperatures
international treaty about global change
in the face of scientific uncertainty, we should behave cautiously
an approach that involves taking CO2 out of the atmosphere. ex: storing carbon in agricultural soils or retiring agricultural land and allowing it to become pasture or forest