CAS ES 107 Chapter Notes - Chapter 1: Carbonate Rock, Sulfate Aerosol, Tropospheric Ozone
7 Jun 2018
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Chapter 1: Global Change
-human activity is accelerating Earth’s changes
-the effects of our actions are seen most clearly in the thin envelope of gases in the atmosphere
-anthropogenic changes→ those caused by humans
-global climate→ the prevailing weather patterns of a planet or region over time, is being altered
by the addition of greenhouse gases to the atmosphere
-greenhouse gases→ gases that warm a planet’ surface by absorbing outgoing infrared radiation
and reradiating it back toward the surface (known as the greenhouse effect)
-this effect is known for Venus’ hot surface temp
-water vapor is a natural greenhouse gas
-the most abundant anthropogenic GG is carbon dioxide (fossil fuels, deforestation)
-when trees are cut down, they decay and carbon in their trunks, branches and leaves is released
as CO2
-volcanic emissions also releases CO2 which is cycled by plant and animals
-ozone layer→ chemically distinct region within the stratosphere and protects earth’s surface
from sun’s harmful ultraviolet radiation
-ozone (O3)→ form of oxygen that is much less abundant and chemically different than the
oxygen we breathe
-ozone hole→ over Antarctica with extremely low ozone concentration is anthropogenic in
origin
-we are decreasing biodiversity because of deforestation
-serious losses of ozone has been confined to the South Pole region
-tropical deforestation and fossil fuel burning causes global warming→ warming of the Earth’s
atmosphere due to an anthropogenic enhancement of the greenhouse effect
Three Major Themes
1. Global environmental issues
2. Global change in the past
a. Climate is a good example of the overlap of short and long time scales of global
change
b. Evidence of past climates has come from cores drilled into the sediments on the
ocean floor
c. Sediments→ layers of unconsolidated material that is transported by water or air
d. Core evidence tells us were are in the middle of a short interglacial period (a
warm interval marked by the retreat of Northern Hemisphere ice sheet) in
between glacial periods (cold intervals marked by the buildup of these ice sheets)
e. So without anthropogenic influence, we will slowly slip into an Ice Age
3. Systems→ group of components that interact
a. Earth system→ has four parts: atmosphere, hydrosphere, biota, and the solid earth
b. Atmosphere→ thin envelope of gases that surrounds earth
c. Hydrosphere→ various reservoirs of water, including ice
d. Cryosphere→ the ice portion of the hydrosphere
e. Biosphere→ biota, all living things
find more resources at oneclass.com
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f. Geosphere→ includes all rocks, or consolidated mixtures of crystalline materials
(minerals), and all unconsolidated rock fragments. Divided into the core, mantle
and crust.
g. Core→ dense mixture of metallic iron and nickel and part solid, part liquid
h. Mantle→thick rocky layer between core and crust and is the largest fraction of
earth’s mass
i. Crust→ thin, outer layer, which consists of light, rocky matter in contact with the
atmosphere and hydrosphere
j. Forcings→ internal and external influences
i. an example of a forcing is the variation in the amount of sunlight received
in each hemisphere during the course of a year. The response to this
forcing, governed by the interaction between the atmosphere and
hydrosphere, is the seasonal cycle of summer and winter.
3 major environmental changes→ global warming, ozone depletion, and tropical deforestation
Global warming
-its complex because it involves many different parts of the earth system
-its controversial because it’s hard to separate to anthropogenic influences and natural ones and
its causes are rooted in our global industrial infrastructure
-greenhouse effect is a real process that keeps surfaces of earth and other planets warmer than
they usually would be in the absence of an atmosphere
-global warming is an increase in earth surface temp brought about by a combo of industrial and
agricultural activities
-a milestone was reached in 2007 with the IPCC and their new report
Keeling Curve
-Charles David Keeling measured the atmospheric concentrations of CO2 on top of Mauna Loa,
a volcano in Hawaii
-the CO2 concentration in late 2007 was 384 ppm, its about that because the concentration
oscillates when forests release CO2 back into the air during winter (opposite in summer)
-its been increasing every year though
CO2 data from ice cores
-if we want to know when increases in CO2 began we have to study the air bubbles trapped in
polar ice
-build-up of CO2 began early in the 19th century, so well before the Industrial Age (1850)
-the rise in CO2 levels between 1800 and 1850 has been attributed to the deforestation in North
America by westward-expansion (pioneer effect)
-humans have been responsible for almost a 40% increase in CO2 concentration over the past
two centuries
Other Greenhouse Gases
-methane (CH4) and nitrous oxide (N2O) are also increasing because of human activity,
primarily agriculture
-N2O is less strongly influenced by humans because it has large natural sources
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
This effect is known for venus" hot surface temp. The effects of our actions are seen most clearly in the thin envelope of gases in the atmosphere. Global climate the prevailing weather patterns of a planet or region over time, is being altered by the addition of greenhouse gases to the atmosphere. Greenhouse gases gases that warm a planet" surface by absorbing outgoing infrared radiation and reradiating it back toward the surface (known as the greenhouse effect) The most abundant anthropogenic gg is carbon dioxide (fossil fuels, deforestation) When trees are cut down, they decay and carbon in their trunks, branches and leaves is released as co2. Volcanic emissions also releases co2 which is cycled by plant and animals. Ozone layer chemically distinct region within the stratosphere and protects earth"s surface from sun"s harmful ultraviolet radiation. Ozone (o3) form of oxygen that is much less abundant and chemically different than the oxygen we breathe.
