Transcript Chapter 2: The Physical Setting

Chapter 2: The Physical World
• Tectonic Plate
Movement
• Climate Controls
• Climate Zones
• Climate Change
1. Tectonic Plate Theory
Figure 1.20
Hazards: earthquakes, volcanoes, tsunamis
Oceanic and
continental
crusts
Subduction
and Orogeny
Convergent,
Divergent, and
Transform
boundaries
Earthquakes of a 5.0 magnitude or greater, over a 10-year period.
Note their relationship to midocean ridges and oceanic trenches.
• Global Controls of Climate
– Latitude
– Land & water distribution
– Atmospheric pressure & winds
– Landform barriers
• Latitude
– Amount of solar energy received over the
course of a year
– Intensity of receipt of solar energy
• Proximity to water (land & water
distribution
– Continentality vs. Temperate
-56 degrees C (-68.8 degrees F), 1/13/2012
Atmospheric Pressure
There are four broad pressure areas in Northern Hemisphere (and
corresponding areas in Southern):
•Equatorial Low-Pressure Trough (marked by the ITCZIntertropical Convergence Zone)
•Polar High-Pressure Cells
•Sub-tropical High Pressure Cells
•Sub-polar Low-Pressure Cells
Atmospheric Pressure & Winds
• Landform Barriers
Global Pattern of Average Annual Rainfall
• Precipitation Sources
– Convectional
– Orographic
– Cyclonic
2. Temperature and Precipitation
3 Types of Precipitation:
Convectional, Orographic, Cyclonic
Orographic Precipitation
Figure 1.23
Cyclonic Precipitation
Climate Zones—Modified Koppen System
• Global Warming
– Causes of global warming
FIGURE 2.4 Solar Energy
and the Greenhouse Effect
The greenhouse effect is the
trapping of solar radiation in the
lower atmosphere, resulting in a
warm envelope surrounding
Earth.
Causes of Global Warming (cont.)
• Anthropogenic (humancaused) pollutants increase
the greenhouse effect
FIGURE 2.5 Increase in CO2 and Temperature These two
graphs show the relationship between the rapid increase of CO2
in the atmosphere and the associated rise in average annual
temperature for the world. The graphs go back 1,000 years and
show that both CO2 and temperature have been relatively stable
until the recent industrial period, when the burning of fossil
fuels (coal and oil) began on a large scale.
Global Climates: An Uncertain
Forecast (cont.)
• Global Warming
– The four major greenhouse gases
• Carbon dioxide (CO2): makes up more than 50%
of anthropogenic greenhouse gases; comes
mainly from burning fossil fuels
• Chlorofluorocarbons (CFCs): about 25% of
human-generated greenhouse gases; come
mainly from aerosol sprays, refrigeration, and air
conditioning
• Methane (CH4): about 15%; caused by burning of
vegetation, by-products of cattle and sheep
digestion, leaking natural gas pipelines, and
refineries
• Nitrous oxide (N2O): 5%; caused by agricultural
chemical fertilizers
• Average global temperature has increased by 1.33◦F from
1880 – 2008
• 11 of 12 warmest years on record since 1850 occurred
between 1995 & 2006
• 8 of the 10 warmest occurred since 2000
• Over last 50 years, average global temperature has
increased at a rate of .23◦F, about twice the rate for the
entire 20th C
• Temperatures in the N. Hemisphere are higher than at
any time in the last 1300 years.
• Since 1961, global ocean temperatures have increased,
to a depth of 3000 m (9800 ft).
• 80% of the heat added to the atmosphere has been
absorbed by the oceans
FIGURE 2.7
Auto Emissions in China In 2006, China surpassed the United States
as the country that emits the most CO2 into the atmosphere. While the
main reason for China’s huge emissions is the widespread use of coal
to generate power, the rapid increase in private auto ownership is an
increasing concern because car traffic has become a major cause of
smoggy skies in China’s urban areas.
Global Climates: An Uncertain Forecast
• Effects of Global Warming
– Computer models and scientists are coming to
agreement on effects
• Average global temperatures will increase 2 to 4°F by 2030;
this rate of increase could double by 2100.
– Same magnitude of cooling that caused the ice age 30,000 years ago
• Major shift in agricultural areas
– Wheat belt could become warmer and drier; lower grain yield
– Canada and Russia could become warmer
– Southern regions of the United States and Europe could become
warmer and drier, requiring irrigation
• Sea levels rise as polar ice caps melt, endangering
low-lying islands and coastal areas around the world—could
rise by 7.1 inches to 23.2 inches
FIGURE 2.6
• Sea ice
off Greenland
during the
summer thaw
• Warming will be greatest over land and in northern high
latitudes
• Summer sea ice will disappear in the Arctic by the end of
the 20th C
• More intense cyclonic storms in tropics; midlatitude
cyclones move poleward
• Increase in rain in high latitudes; decrease in subtropics
over land
• Heat waves; extremes in temperature
• Larger range for tropical diseases
• Wildfire risk increased
• Extinction of species
Global Climates: An Uncertain Forecast
• Globalization & Climate Change: The
International Debate on Limiting Greenhouse
Gases
– Earth Summit—1992, Rio de Janeiro
• First international agreement on global warming (167
countries)
– United States, Japan, India, China failed to meet
emissions reductions
– Earth Summit—1997, Kyoto
• Kyoto Protocol: 38 industrialized countries agreed to reduce
their emissions of greenhouse gases to below 1990 levels
The International Debate on Limiting Greenhouse Gases
• Former United States President Bush opposed Kyoto
Protocol; United States never ratified it
– Complying could damage U.S. economy
– Large developing countries (India, China) were not bound to
reduce greenhouse gases and would have an advantage
– Russia ratified (2004), and Kyoto Protocol became international
Law in early 2005
• Copenhagen: United Nations Climate Change Talks
(December 2009)
– Pact between U.S., China, India, Brazil, South Africa to take
action on global climate change
– Flawed, more intention than action