Exam 3 Flashcards
Balance & Equilibrium
light from the sun carries it to earth, warming it up. Some of the excess energy escapes into space. If energy in = energy out, earth is at equilibrium
Albedo
percentage of solar radiation reflected back into space by an object or surface
Land & Ocean Albedo
low albedos, they absorb a lot - 0.1-0.4
Snow & Ice Albedo
high albedos, they reflect a lot - 0.7-0.9
Earth’s Average Albedo
0.3 or 30%
Greenhouse gasses
the atmosphere allows sunlight in, but prevents heat from escaping
Nitrogen and Oxygen are the two main gases in our atmospheres, but they don’t warm it.
Greenhouse gasses are water vapor, methane, and carbon dioxide
Industrial Age
has contributed to our pollution through natural gas, coal and oil
In the Past
volcanic eruptions used to cause so much carbon dioxide that it reached concentrations 400x hotter than now, but life always survived
Atmospheric layers
Exosphere Thermosphere Mesosphere Stratosphere Troposphere
Without gasses, the Earth’s surface would be ______ cooler
59 degrees
Earth, Venus, Mars
Earth’s atmosphere has only a little amount of CO2: 387ppm, atmosphere is thicker and denser than mars, but not as thick as Venus
Methane traps ____ as much energy as CO2
8x
Ozone layer
only contributes 3%-7% of greenhouse gasses
Blocks UV light, w/out it we couldn’t live here
CFC (chlorofluorocarbons)
coolants in refridgerators and air conditioners responsible for depletion of ozone layer
Human Activities that Produce Greenhouse Gases
burning fossil fuels, breathing, livestock
Offset Gases by
electric cars, less deforestation and using selective cutting instead, forest fires
Trees Burning Produces
lots of CO2
Anthropogenic methane
much of it comes from waste and decay in our landfill, human waste and sewage breaks down into methane
manure from chickens, pigs, cattle, and sheep account for 37% of all human-related methane
Nonhuman sources of Greenhouse Gases
molten rock and magma are rich in CO2, bacteria, frozen soil in the artic
Alternate energy sources
dams, windmills, solar panels, windmills, wave power station
Carbon capture and sequestration
photosynthesis, business factory offsets, preserving forests, some trees don’t produce as much oxygen
Biofuels
made from plant products
CO2 burned in replaced w/plants
not carbon neutral
Hunters & Gatherers
our ancestors got food by hunting for food
omnivores
only animal that practices agriculture
agriculture couldn’t develop until our ancestors had evolved to the point of having foresight and long term planning
Theories
- Oasis Theory. climate became drier, causing suitable habitats to shrink, so people had to live closer together in the small areas that still had food plants
- In areas where cereal grains grew well natural, humans could settle in one spot and still have enough to eat, they did not have to move from place to place
- Even w/out climate change, human population became dense enough that more food was needed to prevent starvation. Pop densities tend to be lower in non ag. societies
