Summary: Climate Change Ecology

Read the summary and the most important questions on Climate Change Ecology

• 2 Chapters

• 2.1 Chapter 2: The Climate System and Change

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• How do clouds both have a cooling and warming effect?

  Clouds in the atmosphere can reflect incoming solar energy, cooling the surface. During the day, this effect can outstrip the warming effect of the water vapor in the clouds, whereas at night the warming effect of clouds dominates.

• Why is the movement water vapor so important in the climate system?

  Because water vapor has powerful heating (greenhouse gas) and cooling (daytime clouds) effects.

• How did the ozone layer allow terrestrial life to emerge?

  With the emergence of the ozone layer, UV radiation was screened out in the upper atmosphere, allowing life-forms to emerge onto land. Photosynthetic organisms were still dominant, allowing the continuing buildup of oxygen in the atmosphere.

• What defines warm als cold periods?

  During cool or cold phases, there is polar ice and substantial ice on land, and the global mean temperature is low. In the warm periods, there is little or no polar ice or ice on land.
  
  The warm periods generally are associated with high atmospheric CO2 levels, whereas the icehouse periods are associated with low CO2

• What are the three main types of orbital variation affecting the Earth’s climate?

  1. Eccentricity
  

  • the shape of the Earth’s orbit around the sun
  • shape varies from more circular to more oval with two cyclic periods—100,000 and 400,000years.
    

  2. Obliquity
  

  • the amount of tilt
  • 41.000 year periodicity

  3. Precission
  

  • the slow rotation of the direction of the tilt
  • 23.000 year periodicity

  
  
  All three of these orbital forcings affect the distribution of heating between seasons or between hemispheres more strongly than they affect the overall amount of solar energy reaching the Earth.
  
  Their effect on climate is therefore due to amplifications and dynamic effects rather than to changes in raw energy input.

• Why does the Northern Hemisphere have a bigger effect than the Southern Hemisphere on the warming and cooling of the whole planet?

  Warming and cooling of the Southern Hemisphere has no such effect because of the lack of land near the poles.
  
  North America and Eurasia have huge landmasses near the poles. When the Northern Hemisphere receives less heat, particularly in summer, ice may form on this land. The ice reflects sunlight and cools the entire planet. When the Northern Hemisphere receives more heat, the ice melts and the planet warms.

• What are the results of a more oval of circular orbit?

  The more circular orbit results in more even distribution of solar energy.
  
  The more oval orbit can result in less solar energy reaching the Northern Hemisphere’s large, ice-prone landmasses and can help trigger a glacial period.

• What is the role of the Southern Hemisphere in the formation and termination of glacial periods?

  Low obliquity (tilt) brings cool summers to both hemispheres, which favors ice buildup in the north and intensified circumpolar current in the south. The intensification of the circumpolar current reduces upwelling of CO2-rich water. The reduction in atmospheric CO2 cools the planet, facilitating continental ice sheet buildup in the north.
  
  This effect is reversed at the end of glacial periods.

• What principle direves the atmospheric circulation?

  Warm air is less dense than cool air and therefore rises.

• What is the main route of heat transport?

  Warm air rises and builds up in the tropics, pushing toward the cooler poles. As air masses move from the tropics toward the poles, they cool, descend, and eventually return to the tropics in a giant loop.