ERTH 535:
Planetary Climate Change
(Spring 2018)
Pre-class Quiz #7:
Recent and Future Climate
Dr. Dave Dempsey
Dept. of Earth & Climate Sci.
SFSU

This is a "preview" version of Pre-class Quiz #7. The preview version is suitable for printing and leisurely inspection before you submit your answers to the interactive or "live" version—that is, the real thing. When you feel ready to submit your answers, go to iLearn's ERTH 535 "Pre-class Quiz" section, select the interactive version, and follow its instructions.

(Responses must be submitted via iLearn by 10:30 a.m. on Monday, May 21.)

Description: The questions below pertain to recent and future global climate. They are based on Reading Assignment #15.

Questions:

(1) Multiple Answer. Volcanic eruptions and global mean surface temperature. What impact to major volcanic eruptions have on global-mean surface temperature, and for how long? (Select the one best answer.)

  1. Volcanoes inject sulfur dioxide into the stratosphere, where it forms sulfate aerosols that reflect sunlight, cooling the surface for up to several years.
  2. Volcanoes inject sulfur dioxide into the stratosphere, where it forms sulfate aerosols that reflect sunlight, cooling the surface for many decades.
  3. Volcanoes inject smoke, dust, and ash into the troposphere and stratosphere, where these aerosols absorb solar radiation, warming the surface for up to several years.
  4. Volcanoes inject smoke, dust, and ash into the troposphere and stratosphere, where these aerosols absorb solar radiation, warming the surface for many decades.

(2) Multiple Choice. Solar cycles and global mean temperatures. What impact do sunspot and other, decade-to-century scale cycles in solar output have on global mean temperatures? (Pick the one best answer.)

  1. Such solar cycles can't explain observed variations in global mean temperatures at any time during the Holocene.
  2. Such solar cycles might help explain some changes in global mean temperatures, but their magnitudes are very small and no one can yet explain how they could do it.
  3. Such solar cycles have significant, well established effects on global mean temperatures.
  4. Such solar cycles have been the most important contributor to observed variations in global mean temperatures during the Holocene.

(3) Multiple Choice. Future carbon dioxide concentrations. What would happen to atmospheric carbon dioxide concentrations if humans immediately reduced current consumption rates of fossil fuels back to the rates in 2000 or 1990, and kept them there? (Pick the one best answer.)

  1. CO2 concentrations would immediately fall to levels observed in 2000 or 1990.
  2. CO2 concentrations would stop rising and remain steady near today's level (389 ppm).
  3. CO2 concentrations would continue to rise, but more slowly than they are rising today.
  4. CO2 concentrations would continue to rise, at least as fast as they are rising today.

(4) Multiple Choice. Attribution of observed global warming. What is one strong piece of evidence that global warming observed in the last 40 years has been due mostly to anthropogenic greenhouse warming? ("Anthropogenic" means "caused by humans".) (Pick the one best answer.)

  1. Humans have been burning fossil fuels at increasing rates in the last 40 years.
  2. Carbon dioxide, methane, nitrous oxide, and chlorofluorcarbon gas concentrations have all been increasing in the last 40 years.
  3. Global climate models reproduce the observed warming well with the effects of anthropogenic greenhouse gas emissions included, but not otherwise.
  4. Most active climate scientists believe that global warming is largely anthropogenic.


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