PHY 237 Flashcards
The densest part of the atmosphere extends only ____ above the surface
a few kilometers
___ is the dominant form of energy in the atmosphere
radiation
____ is a measurement of the heat content of air at a location and time
temperature
Temperature depends on
how much radiation is present
Greenhouse gases
certain gases in the atmosphere that absorb radiation emitted by the earth
The atmosphere serves to
keep the earth warmer than it would be
The _____ is a property of minor gases
greenhouse effect
Greenhouse gases
CO2
CH4
O3
CFC
N2O
H2O (vapor)
Intergovernmental Panel on Climate Change
Established in 1988 - function to periodically report on climate changes to member countries of the UN
Carbon Dioxide
concentration increases by 1 to 3 ppm every year
Carbon Dioxide and Plants
Plants remove CO2 from the atmosphere by photosynthesis
Plants release CO2 through respiration
CO2 concentration decreases in Spring/Summer and increases in Fall/Winter
Methane (CH4)
Accounts for ~9.5% of all greenhouse gas emissions from human activities
Methane is produced by
bacteria acting on organic material in oxygen-free environments
Natural gas is about ___% methane
90%
CH4 is removed from the atmosphere through
bacterial processes in soil and chemical reactions
Methane’s lifetime in the atmosphere is [longer/shorter] than CO2
shorter
Methane is [more/less] efficient at trapping radiation than CO2
More
Ozone (O3) can be good or bad for your health depending on
where in the atmosphere it is found
Stratospheric ozone
considered good because it abosrbs ultraviolet radiation from the sun and protects living things
Tropospheric ozone
bad for the environment because it triggers a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma
The EPA
Environmental Protection Agency regulations help states reduce ozone levels in outdoor air
How ground-level ozone is formed
Tropospheric ozone is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds - this happens when pollutants emitted by cars, power plants, chemical plants, etc, chemically react in the presence of sunlight
Ozone is the most likely to reach unhealthy levels
on hot sunny days in urban environments
Ozone can be transported by
wind, so even rural areas can experience high ozone levels
At any given time, ozone molecules are constantly formed and destroyed in the
stratosphere
The Ozone Hole
In 1985, a dramatic decrease in stratospheric Ozone was detected over Antartica
H2O as a positive feedback mechanism
Warming by CO2 –> more H2O in atmosphere –> more warming because water is a greenhouse gas –> more water is evaporated
Global Warming Potential (GWP)
a measure of how much radiation energy one ton of an atmospheric gas will absorb over a specific period relative to one ton of CO2
Impact of Aviation
air travel is responsible for ~5% of human-caused global warming
Contrail clouds
line-shaped clouds produced by aircraft engines exhaust typically at aircraft cruising altitudes
Contrails are formed primarily of
water (ice crystals)
CORSIA
Carbon Offsetting and Reduction Scheme for International Aviation
an agreement by the UN calling on airlines to reduce greenhouse emissions in international flights by using lighter fuels, using airplanes of lighter materials, improved aircraft design, and modifying flying patterns
Carbon Intensity
how much fossil fuel is burned to produce a certain economic output; not the amount of carbon emitted, but a number prorated by the gross domestic product (GDP)
If the GDP and emissions both increase by 5 percent in a given year, the carbon intensity would
remain unchanged
Factors contributing to decline in US CO2 Emissions
major shift from coal to natural gas
higher automobile emission standards
popularity of electric vehicles
decreasing the cost of solar energy
