8/14/2019 POS - Global Warming

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Nathaniel Kan

Perspectives on Science Questions

Global Warming

1. What is the greenhouse effect?

Energy is being constantly absorbed and released by the Earth. High energy light emitted

from the sun travels to Earth. Some of this light is reflected, depending of the albedo of

the area of the Earth, and some of this light is absorbed. If these were the only forcesacting to determine the temperature of the Earth, we could find the temperature by taking

the energy absorbed by the Earth and subtracting that which is reflected and emitted.

However, one also must take into account the greenhouse effect. Certain gases in the

atmosphere of the Earth are transparent to high energy light, but absorb low energyinfrared light. These greenhouse gases prevent some of the heat from leaving the Earth,

resulting in a warmer climate than otherwise.

2. What is special about greenhouse gases?

Greenhouse gases, such as CO2, CH4, H2O, unlike the large part of our atmosphere, madeup of N2, O2, Ar, absorb heat from the sun. Like the glass of a real greenhouse, these

gases allow light and heat in, but only allow some heat back out. This results in an overall

increase in the temperature of the planet. The more greenhouse gases in the atmosphere,the higher temperature the climate will become.

3. Why is the carbon budget so important?

The carbon budget is the amount of free carbon in the atmosphere. While our planet

naturally goes through cycles in the climate, the amount of carbon based gases, such asCO2 or CH4 will directly affect the temperature, because of the nature of the gases asexplained in (2). Up until the beginning of the Industrial Revolution, the carbon budget

was relatively static. After we began burning fossil fuels, however, new carbon was

released into the atmosphere. Since that time, we have been able to detect a noticeableincrease in the world carbon budget.

4. How are the earth's orbit parameters and sunspot cycles related to the climate?

There have been hypotheses that the earths orbit and the suns sunspot cycles do affect

the climate. We do not, however, know a direct correlation for either. The orbit of the

earth would affect the distance from the sun at different periods during the year, whichwould affect how much radiation from the sun reaches the earth, thus affecting the

climate. As for sunspot cycles, correlations have been drawn to the climate, however,

these require arbitrary scaling on the part of the observer. We do not know any directcorrelation.