Earth Science, 10^th edition

Chapter 19: Climate

 

    I. The climate system

       A. Climate is an aggregate of weather

       B. Involves the exchanges of energy and moisture that occur among the

             1. Atmosphere

             2. Hydrosphere

             3. Solid Earth

             4. Biosphere, and

             5. Cryosphere (ice and snow)

 

  II. World climates

       A. Every location has a distinctive climate

       B. The most important elements in a climatic description are

             1. Temperature, and

             2. Precipitation

 

III. Climate classification

       A. Brings order to large quantities of information

       B. Many climatic-classification systems have been devised

       C. Köppen classification of climates

             1. Best known and most used system

             2. Uses mean monthly and annual values of temperature and precipitation

             3. Divides the world into climatic regions in a realistic way

             4. Boundaries Köppen chose were largely based on the limits of certain plant associations

             5. Five principal climate groups

                  a. Humid tropical (A)

                  b. Dry (B)

                  c. Humid middle-latitude with mild winters (C)

                  d. Humid middle-latitude with severe winters (D)

                  e. Polar (E)

             6. A, C, D, and E climates are defined on the basis of temperature characteristics

             7. Precipitation is the primary criterion for the B group

 

 

IV. Human impact on global climate

       A. Humans have been modifying the environment over extensive areas for thousands of years

             1. By using fire

             2. By overgrazing of marginal lands

       B. Most hypotheses of climatic change are to some degree controversial

       C. Global warming

             1. Water vapor and carbon dioxide absorb heat and are largely responsible for the

                  greenhouse effect of the atmosphere

             2. Burning fossil fuels has added great quantities of carbon dioxide to the atmosphere

       D. The atmosphere response

             1. Global temperatures have increased

                  a. Balance of evidence suggests a human influence on global climate

                  b. Globally averaged surface temperature is projected to increase by 1.4 to 5.8°C by the

                      year 2100

             2. The role of trace gases

                  a. Atmospheric race gasses

                      1. Methane

                      2. Nitrous oxide

                      3. Certain chlorofluorocarbons

                  b. Absorb wavelengths of outgoing Earth radiation

                  c. Taken together, their warming effects may be nearly as great as carbon dioxide

              

VI. Climate feed-back mechanisms

       A. Possible outcomes of altering the climate-system

       B. Two types

             1. Positive -feedback mechanisms reinforce the initial change

             2. Negative-feedback mechanisms produce results that are just the opposite of the initial

                  change and tend to offset it

 

 VII. Some possible consequences of global warming

       A. Altered distribution of the world’s water resources and the affect on the productivity

             of agricultural regions

       B. Rise in global mean sea level

       C. Changing weather patterns

             1. Higher frequency and intensity of hurricanes

             2. Shifts in the paths of large-scale cyclonic storms

                                    3. Changes in frequency