IDS 102
Climate Change & Greenhouse
Concept Review/ End of Module Questions
On February 2, 2007, the Intergovernmental Panel on Climate Change concluded that “Global warming is very likely caused by man, meaning more than 90 percent certain.” That's the strongest expression of certainty to date from the panel. They also announced that if nothing is done to change current emissions patterns of greenhouse gases, global temperature could increase as much as 11 degrees Fahrenheit by 2100. But if the world does get greenhouse gas emissions under control something scientists say they hope can be done the best estimate is about 3 degrees Fahrenheit. ( Consider how these changes will influence our planet in the end of module questions.
1) As global temperatures rise, what will happen to the size of the polar ice caps and mountain snow pack? Why? How will this change global sea-levels?
Polar Ice Caps will melt and in most places glaciers & mountain snow pack will be reduced. This will result in sea-levels rising. The melting of polar ice caps will also decrease the Earth’s albedo, thus increasing the amount of energy the surface absorbs. This decreased albedo will thus result in an increase in temperatures at the poles
2) Given that the snow pack in the Cascades provide water to streams in the summertime and thus supplies much of the water that is used by cities in Western Washington and farmers in Eastern Washington, discuss how will increased temperature influence the fresh water supply in Washington State. Consider how the amount of snow that melts in the spring (the rate of spring melting) increase or decrease and how will this affect water levels in local rivers and the number of spring flooding events as well as how will the summertime level of local rivers will change? How will our ability to generate hydroelectric power in the summertime be affected?
Currently, a large amount of precipitation falls as snow in the winter. A small amount of this snow becomes incorporated in mountain glaciers while most of it melts slowly in the following spring and summer, supplying water to many rivers during the summer months in which we get little or no rain.
As temperature start to warm, the snowpack and glaciers will start to melt at a faster rate in the spring. This means that spring floods will increase while river levels drop dramatically in the summer. We are currently seeing decreased summer snow pack and a corresponding drop in the level of rivers in the summertime.
Eventually we may start to see our rivers run dry in the summer. This will make it more difficult to generate hydroelectric power in the summer.
3) Tropical rainforests are disappearing at a rate of 10-20 million hectares (1 hectare = 2.5 acres) per year. What effect would removing the tropical rainforests have on CO2 concentration in the atmosphere and why?
Fewer tree will result in less photosynthesis, which will result in less CO2 forming into plant matter and thus CO2 levels in the atmosphere will rise.
4) Given that tropical storm intensity is related to ocean temperature, (warmer waters contribute to stronger storms), how would you expect the intensity of tropical storms to change with global warming?
The intensity of tropical storms will increase and the number of intense tropical storms will also increase.
5) In many places, the length of the growing season (= time that is frost free) is increasing as we see increased global warming? This might seem to be beneficial to farming, but so far we have not seen an increased crop yield. Suggest at least 2 negative effect of global warming that might contribute to decreased crop yields.
Warmer winters mean that more insect pests will survive the winter, thus total number of insect pests may increase and may increase crop damage.
Increased temperatures can result in an increase in the evaporation rate of water from the soil, thus drought conditions may increase even if rainfall does not change.
6) Below is a crude diagram of a greenhouse with a glass roof, which is transparent to visible light, but is NOT transparent to infrared radiation. Assume that the light source only emits visible light. Describe why the temperature inside the greenhouses is warmer than the outside temperatures by circling the correct type of radiation (visible light and/or infrared) and the process (absorption, emission, etc.)
7) Below is a crude diagram of the surface of the moon. The moon is light by light from the sun, but the moon does not have an atmosphere that will absorb either visible light or infrared light. Describe what happens to visible light from the sun that hits the moon’s surface and determine if the surface of the moon will be warm or cold.
Most of the visible light from the sun is absorbed by the surface of the moon, while a small fraction (about 10%) is reflected. The moon’s surface then emits IR radiation, which is radiated out to space. Because the moon does not have an atmosphere to trap the IR radiation, no heat builds up and the moon is thus a very cold place.
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