Team Questions Session 3

  1. Understanding Earth’s energy balance is essential to understanding the issue of global warming. For example, the solar energy striking Earth’s surface averages 168 watts per square meter (W/m2), but the energy leaving Earth’s surface averages 390 W/m2. Why isn’t the Earth cooling rapidly?

There are other types of energy that are heating up the earth other than solar energy, such as geothermal and nuclear energy. These energy, from various human’s activities, contribute to the amount of heat on Earth too. Hence, the amount of heat energy present on Earth may be much higher than 168 W/m2 and may require more than the 390 W/m2 leaving the Earth to observe a net cooling effect.

The other reason is that the atmospheric counter radiation will reflect some of the energy back. Greenhouse gases also absorb and preserve the radiation energy in both ways. Thus, Earth will not cool rapidly since much of the heat energy is retained by the atmosphere.

See details of the Earth’s energy balance (source):

  1. Do you think the statement made by the cartoon is justified? Explain.

The logic of the cartoon characters is that the heavy snow in the winter indicates global warming is less of an issue. However, this logic is faulty for that global warming stands for ascending trend of global average temperature. An extreme case, such as an extremely strong winter in a location as seen from the cartoon, will not be representative in the global point of view.

On the other hand, global warming will cause various drastic weather conditions. In this case, global warming causes water to evaporate and increase the atmospheric moisture content in the prior season. Therefore, the snow in the winter is heavier.

Considering ocean circulation, global warming will decrease the ocean circulation. Thus, in some specific region, the winter will be colder as well.

  1. One of the first radar devices developed during World War 2 used microwave radiation of a specific wave range that triggers the rotation of water molecules. Why was the design not successful?

Microwave is not efficient for long-distance transmission as it can trigger water molecules to rotate in the air and energy will be lost in the process. This may lead to an incomplete transfer of information if used for transmitting data. One may tried to use a waveguide to reduce the loss of energy during transmission but this is not practical during WW2. Furthermore, technology at that time may be less advanced and they may be lacking a high power source transmitter for it to be feasible.

  1. Now that you have studied air quality (Unit 1), stratospheric ozone depletion (Unit 2), and global warming (Unit 3), which do you believe poses the most serious problem for you in the short run? In the long run?

Short Run

Air Quality will pose the most serious problem for us because it is directly related to our daily lives and a problem in the air quality, such as a high concentration of Carbon Monoxide, can lead to death straightaway. In comparison, effects of ozone depletion and global warming will take a longer time to take effect.

Long Run

Global warming will pose the most serious problem for us in the long run because its effects forms a vicious cycle that worsens each other. As time goes by, it will get worse and worse. For example, the melting of ice cap causes a rise in sea level, and at the same time it will also causes Carbon Dioxide trapped in the air to be released into the air. With more greenhouse gases, like carbon dioxide, the effects of melting ice cap will speed up forming the vicious cycle.

Ozone depletion and Air Quality may worsen, but it does not form a vicious cycle like global warming.