Question 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 Earth cooling rapidly.

According to the first law of thermodynamics, energy is conserved (cannot be created or destroyed). The earth receives the heat energy from the sun and it can release the heat by emitting radiation. In order to keep the temperature of the earth to be equilibrium, the energy from the sun has to be balanced with the heat radiated by the earth. The solar energy striking Earth’s surface averages 168 W/m². However, the energy leaving Earth’s surface averages 390 W/m². The earth is not cooling rapidly because some of the heat is coming from the Earth’s interior and continuously flow into the surface. The long-lived radioactive decays of uranium and other radioactive elements in the interior of the earth keep the earth in high temperature. So the heat emitted by the earth need to be balanced with the heat energy from the sun and from the interior of the earth. Even the heat released by the earth is larger than the heat received from the sun, the earth will not cool down rapidly because the interior of the earth will keep the heat flowing.

Question 2:

“This winter has lowered my concerns about global warming …” Decide and explain where the statement is correct or incorrect.

The statement is incorrect. Snowing does not show that there is less global warming. In all storms, the main source of precipitation is the moisture already in the atmosphere at the start of the storm. Thus, the more moisture in the environment, it rains or snows harder. In mid winter (December-February), as long as it does not warm beyond freezing, rise in temperature leads to greater snowfall. This is because increased moisture leads to greater snowfall, and the atmosphere can hold 4% more moisture for every 1 F increase in temperature. In fact, the amount of snowfall at 32 F would be at least double that at 14 F. Thus, heavier snowfall might actually show that temperatures in the atmosphere are rising, though not warming beyond freezing, thus increasing moisture which leads to heavy snowfall.

Question 3:

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

As the microwave radiation travels through the air to detect an object, water in the atmosphere absorbs that microwave radiation. The microwave energy thus triggers the rotation of water molecules. Besides, the objects they want to detect are also been triggered by microwave radiation. As a result, the signal of the intended object was mixed with the signal of the water. Hence, the design of the radar device was not successful.

Question 4: 

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 (pick one and explain)? In the long run (pick one and explain why)?

Deteriorating air quality would definitely pose the greatest threat in the short term as its effects are felt almost immediately. The ongoing haze issue which has implicated Singapore annually proves that most if not all of society are susceptible to worsening air quality. Within a short period of time of the burning, Singaporeans have felt the difference in the quality of air in the atmosphere. The urgency of this issue, coupled with the lack of resolution without involving political trivia, results in air quality being a dangerous problem in the short run.

Global warming could prove to be a catastrophic occurrence in the long run. Very few humans could possibly escape its presumed wrath should it happen. The truly frightening thing is that we know how we are contributing to its impending arrival but we are not doing a lot more to slow it down.