Learning Objectives
After reading and studying this chapter, students should:
• Know the tools used for studying Earth system science and global change.
• Understand the science of climate change and global warming.
• Know some of the potential impacts of global warming and how they might be minimized.
• Know how global climate change is linked to ozone depletion.
Chapter Summary
This chapter focuses on aspects of climate, climatic processes, and climate change. The chapter opens
with discussions of Earth system science and its place in the study of global change, of tools for
Chapter Outline
I. Global change and Earth system science: an overview
A. Preston Cloud’s central goals of Earth science
2. apply that understanding to better manage our environment
B. Earth system science
2. Earth system science studies Earth as a system with interrelated components
C. The geologic record
2. organic material
3. glacial ice
D. Real-time monitoring
1. regular collection of data for a specific purpose
2. methods vary with subject being measured
E. Mathematical models
1. numerical methods to represent real-world phenomena and linkages between processes
2. climate models
II. Earth’s climate and atmosphere
A. Overview
3. major climatic zones
4. troposphere: lower 7–18 kilometers of atmosphere, where dramatic water vapor variations
1
18
8
Global Climate Change
90
2. mixture of nitrogen, oxygen, trace gases and other compounds
III. The greenhouse effect
A. Earth’s energy balance
1. three factors determine temperature of Earth: amount of sunlight received, amount of sunlight
reflected, atmospheric retention of heat
3. solar energy is in form of electromagnetic radiation
5. greenhouse effect is a natural phenomenon, with recent human perturbations
IV. How we study past climate change
A. Records
1. Instrumental
2. Historical
3. Paleo-proxy
a. tree rings
b. pollen
c. corals
d. carbon-14
e. carbon dioxide
f. methane
V. Global warming
A. Overview
1. global warming is defined as the observed increase in the average temperature of the near-
surface land and ocean environments of Earth
3. human processes in the past 100 years have contributed significantly to global warming
B. Recent global warming
2. the atmospheric concentrations of greenhouse gases have been increasing
3. carbon dioxide measurements
C. Global temperature change
1. variations in Earth’s temperature since the Pleistocene
a. Eemian Interglacial period
D. Warming trends in the past 1000 years
1. 1100–1300 AD: major warming trend
3. 1970s–present: most of increase in last century since 1970
E. Why does climate change?
1. Milankovitch cycles: long-term cycles in climate
a. climate forcing: an imposed change of Earth’s energy balance
F. Solar forcing
1. variability of solar energy over the past 1000 years
G. Volcanic forcing
2. Mt. Pinatubo eruption
H. Anthropogenic forcing
2. industrial age forcing due mostly to emissions of carbon dioxide
4. human activities also cause global dimming, which has a cooling effect
VI. Potential effects of global climate change
A. Magnitude of warming
B. Glaciers and global warming
2. important in landscape development and erosion
C. Glaciers and the cold climate phenomenon
2. glaciation
a. snow compressed into glacial ice
b. continental glaciers/ice sheets
3. permafrost
a. permanently frozen ground
4. loess
a. windblown silt
b. movement
D. Melting of glacial ice, sea ice, and thawing of permafrost with global warming
1. accelerated melting of mountain glaciers
3. positive feedback cycle
5. Antarctic peninsula
6. thawing of permafrost
E. Climate patterns
1. effects on agriculture (see A Closer Look: Desertification)
3. El Niño as an example of climate change causing hazardous events
F. Sea level rise
G. Changes in the biosphere
1. shifts in range of plants and animals, including disease-carrying mosquitoes
3. marine ecosystems
H. Adaptation of species to global warming
2. new vs. old models
I. Strategies for reducing the impact of global warming
1. reduction of greenhouse gases
3. energy planning emphasizing fossil fuel reduction
5. geologic sequestration of carbon
6. rate of climate change could be rapid (see A Closer Look: Abrupt Climate Change)
VII. Coupling of global change processes: Ozone depletion and global warming
A. Ozone depletion
2. CFCs are also strong greenhouse gases
B. Other couplings of global change processes
2. fossil fuels and volcanic eruptions produce particulates, which lead to cooling
3. examples of environmental unity in action
Answers to Review Questions and Critical Thinking Questions
Review Questions
1. Preston Cloud’s central goals for the Earth sciences are: a. understand how Earth works and how it
7. The three main factors that determine the temperature of Earth are the amount of solar energy
8. The main evidence that late 20th century warming is attributable to human activities is that the recent
11. Major potential effects of global warming include changes in climate patterns (and, consequently,
12. The main ways to reduce carbon dioxide emissions are improved engineering of fossil fuel-burning
14. CFCs and carbon dioxide are both greenhouse gases that have been implicated in global warming.
Critical Thinking Questions
1. This question could focus on a number of areas, including increasing mechanization of travel,
2. An answer to this question will reflect the mindset of the student, but should focus on topics such as
climate change, water resource issues, air and water quality, and others.
3. An answer to this question will reflect the attitudes of the student toward scientific certainty, and
4. This question deals with the cycles of the ice ages and where Earth lies now in those cycles. To
answer this question accurately, the student may need to research scientific understanding of the ice
5. This question is closely related to question 3. In addition to addressing issues of scientific certainty,