![College Physics: A Strategic Approach (3rd Edition)](https://www.bartleby.com/isbn_cover_images/9780321879721/9780321879721_largeCoverImage.gif)
The Greenhouse Effect and Global Warming
Although seasons come and go, on average the earth’s climate is very steady. To maintain this stability, the earth must radiate thermal energy—electromagnetic waves—back into space at exactly the same average rate that it receives energy from the sun. Because the earth is much cooler than the sun, its thermal radiation is long-wavelength infrared radiation that we cannot see. A straightforward calculation using Stefan's law finds that the average temperature of the earth should be –18°C, or 0°F, for the incoming and outgoing radiation to lie in balance.
This result is clearly not correct; at this temperature, the entire earth would be covered in snow and ice. The measured global average temperature is actually a balmier 15°C, or 59°F. The straightforward calculation fails because it neglects to consider the earth’s atmosphere. At visible wavelengths, as the figure shows, the atmosphere has a wide “window” of transparency, but this is not true at the infrared wavelengths of the earth’s thermal radiation. The atmosphere lets in the visible radiation from the sun, but the outgoing thermal radiation from the earth sees a much smaller “window.” Most of this radiation is absorbed in the atmosphere.
Thermal radiation curves for the sun and the earth. The shaded bands show regions for which the atmosphere is transparent (no shading) or opaque (shaded) to electromagnetic radiation.
Because it’s easier for visible radiant energy to get in than for infrared to get out, the earth is warmer than it would be without the atmosphere. The additional warming of the earth’s surface because of the atmosphere is called the greenhouse effect. The greenhouse effect is a natural part of the earth’s physics; it has nothing to do with human activities, although it’s doubtful any advanced life forms would have evolved without it.
The atmospheric gases most responsible for the greenhouse effect are carbon dioxide and water vapor, both strong absorbers of infrared radiation. These greenhouse gases are of concern today because humans, through the burning of fossil fuels (oil, coal, and natural gas), are rapidly increasing the amount of carbon dioxide in the atmosphere. Preserved air samples show that carbon dioxide made up 0.027% of the atmosphere before the industrial revolution. In the last 150 years, human activities have increased the amount of carbon dioxide by nearly 50%, to about 0.040%. By 2050, the carbon dioxide concentration will likely increase to 0.054%, double the pre-industrial value, unless the use of fossil fuels is substantially reduced.
Carbon dioxide is a powerful absorber of infrared radiation. And good absorbers are also good emitters. The carbon dioxide in the atmosphere radiates energy back to the surface of the earth, warming it. Increasing the concentration of carbon dioxide in the atmosphere means more radiation: this increases the average surface temperature of the earth. The net result is global warming.
There is strong evidence that (he earth has warmed nearly 1°C in the last 100 years because of increased greenhouse gases. What happens next? Climate scientists, using sophisticated models of the earth’s atmosphere and oceans, calculate that a doubling of the carbon dioxide concentration will likely increase the earth’s average temperature by an additional 2°C (≈ 3°F) to 6°C (≈9°F) There is some uncertainty in these calculations; the earth is a large and complex system. Perhaps the earth will get cloudier as the temperature increases, moderating the increase. Or perhaps the arctic ice cap will melt, making the earth less reflective and leading to an even more dramatic
But the basic physics that leads to the greenhouse effect, and to global warming, is quite straightforward. Carbon dioxide in the atmosphere keeps the earth warm; more carbon dioxide will make it warmer. How much warmer? That’s an important question, one that many scientists around the world are attempting to answer with ongoing research. But large or small, change is coming. Global warming is one of the most serious challenges facing scientists, engineers, and all citizens in the 21st century.
The following questions are related to the passage “The Greenhouse Effect and Global Warming” on the previous page.
The thermal radiation from the earth’s surface peaks at a wavelength of approximately 10 μm. What is the energy of a photon at this wavelength?
- A. 2.4 eV
- B. 1.2 eV
- C. 0.24 eV
- D. 0.12eV
![Check Mark](/static/check-mark.png)
Want to see the full answer?
Check out a sample textbook solution![Blurred answer](/static/blurred-answer.jpg)
Chapter P Solutions
College Physics: A Strategic Approach (3rd Edition)
Additional Science Textbook Solutions
College Physics (10th Edition)
College Physics
University Physics Volume 2
University Physics (14th Edition)
Introduction to Electrodynamics
The Cosmic Perspective (8th Edition)
- Ozone layer One method of estimating the thickness of the ozone layer is to use the formula In Io - In I = kx, where I, is the intensity of a particular wavelength of light from the sun before it reaches the atmosphere, I is the in- tensity of the same wavelength after passing through a layer of ozone x centimeters thick, and k is the absorption con- stant of ozone for that wavelength. Suppose for a wave- length of 3176 X 10 8 cm with k - 0.39, Io/I is measured as 1.12. Approximate the thickness of the ozone layer to the nearest 0.01 centimeter.arrow_forward1. If microwaves have a longer wavelength than ultraviolet waves, which type of wave has less energy? A. ultraviolet B. microwaves C. Both types of waves have the same energy. D. Wavelength cannot be used to determine energy. Gamma rays are the highest energy waves in the electromagnetic spectrum. Using the diagram which region would BEST represent gamma rays? A 2. A. Region A B. Region B C. Region C D. Region Darrow_forwardRadio waves have the lowest frequency of all the electromagnetic waves. What does the frequency of radio waves say about the energy they carry? a.Radio waves carry high amounts of energy. b.Radio waves carry low amounts of energy. c.The energy carried in all Electromagnetic waves is the samearrow_forward
- 1. Which part of the electromagnetic spectrum has a higher frequency than ultraviolet waves? a. infrared b. microwaves c. x-rays d. none of these 2. Which part of the electromagnetic spectrum has a longer wavelength than visible light? a. gamma rays b. radio waves c. ultraviolet waves d. X-rays 3. Which of the given regions of the electromagnetic spectrum are arranged according to decreasing wavelength? a. X-rays, gamma rays, ultraviolet, infrared b. microwaves, infrared, gamma rays, X-rays c. gamma rays, X-rays, microwaves, radio waves d. radio waves, microwaves, X-rays, gamma raysarrow_forwardCan you do 1-6arrow_forwardWhich of the following lists electromagnetic radiations from lowest to highest energy? A. radio waves, microwaves, ultraviolet radiation, visible light B. microwaves, radio waves, visible light, X-rays C. radio waves, infrared radiation, visible light, ultraviolet radiation D. gamma radiation, infrared radiation, visible light, X-raysarrow_forward
- Which of the following is NOT related to the contradiction between Maxwell’s theory of electromagnetism and Newton’s laws of mechanics? A. Maxwell’s theory implies that the speed of light is constant in all inertial frames of reference. B. Einsteinian relativity proves that ether, which is thought to be the medium of light, does not exist. C. Newtonian laws show that magnitude of quantities like speed vary according to inertial frames. D. Galilean transformations predict that light speed in an inertial reference frame would be c’ = c + v.arrow_forwardAnswer these climate physics questionsarrow_forwarda. Violet light has a higher frequency and shorter wavelength than red light. b. Violet light has a lower frequency and shorter wavelength than red light.c. Violet light has a higher frequency and longer wavelength than red light. d. Violet light has a lower frequency and longer wavelength than red light.arrow_forward
- #2arrow_forwardIn the Michelson-Morley experiment of 1887, the speed at which light traveled through vacuum in perpendicular directions was measured to high accuracy. The data indicated that light traveled at exactly the same speed, independent of which direction it traveled. From this data, scientists concluded that: Select one: a.the speed that light travels through vacuum depends on the speed of the source of light b.light behaves like a stream of particles c.light can eject electrons from a metal surface d.light does not require a medium - it may travel through vacuumarrow_forwardThe frequency range for AM radio is 540 to 1600 kHz. The frequency range for FM radio is 88.0 to 108 MHz. a) Calculate the minimum wavelength for AM radio in meters. b) Calculate the maximum wavelength for FM radio in meters. c) Caculate the minimum wavelength for FM radio in meters.arrow_forward
- AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStaxPhysics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College
![Text book image](https://www.bartleby.com/isbn_cover_images/9781938168284/9781938168284_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781337553278/9781337553278_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781337553292/9781337553292_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781938168000/9781938168000_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781337672252/9781337672252_smallCoverImage.jpg)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781938168161/9781938168161_smallCoverImage.gif)