Green House - Comprehension Worksheet
There are two meanings of the term "greenhouse effect". There is a "natural" greenhouse effect that keeps the Earth's climate warm and habitable. There is also the "man-made" greenhouse effect, which is the enhancement of Earth's natural greenhouse effect by the addition of greenhouse gases from the burning of fossil fuels (mainly petroleum, coal, and natural gas). The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in the atmosphere warm a planet's lower atmosphere and surface. It was proposed by Joseph Fourier in 1824 and was first investigated quantitatively by Santé Arrhenius in 1896.
We need to first understand "infrared radiation". Greenhouse gases trap some of the infrared radiation that escapes from the Earth, making the Earth warmer that it would otherwise be. You can think of greenhouse gases as sort of a "blanket" for infrared radiation--it keeps the lower layers of the atmosphere warmer, and the upper layers colder, than if the greenhouse gases were not there. Naturally occurring amounts of greenhouse gases have a warming effect of about 33 °C (59 °F). The major greenhouse gases are water vapor, which causes about 36–70% of the greenhouse effect; carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone (O3), which causes 3–7%. Clouds also affect the radiation balance through cloud forcing similar to the greenhouse gases.
About 80-90% of the Earth's natural greenhouse effect is due to water vapor, a very strong greenhouse gas. The remainder is due to carbon dioxide, methane, and a few other minor gases.
It is the carbon dioxide concentration that is increasing, due to the burning of fossil fuels (as well as from some rainforest burning). This is the man-made portion of the greenhouse effect, and it is believed by many scientists to be responsible for the global warming of the last 150 years.
Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radioactive forcing from CO2, methane, troposphere ozone, CFCs and nitrous oxide. The concentrations of CO2 and methane have increased by 36% and 14% respectively since 1750. These levels are much higher than at any time during the last 800,000 years, the period for which reliable data has been extracted from ice cores. Less direct geological evidence indicates that CO2 values higher than this were last seen about 20 million years ago. Fossil fuel burning has produced about three-quarters of the increase in CO2 from human activity over the past 20 years. The rest of this increase is caused mostly by changes in land-use, particularly deforestation.
(A) does not affect the atmosphere of earth.
(B) changes the colour of all houses on earth to green.
(C) warms the earth’s lower atmosphere.
(D) warms the earth’s upper atmosphere.
(A) to the cooling of the polar regions.
(B) to the green house effect.
(C) to the increase in level of water in the oceans.
(D) to decrease in the size of the earth.
(A) water vapour (B) CO2
(C) Ozone (D) methane
Multiple Choice Questions (with more than one option):
(A) deforestation (B) burning of fossil fuels
(C) industrial revolution (D) fishing
(A) carbon- di- oxide (B) oxygen
(C) methane (D) hydrogen
Fill in the blanks:
fossil fuel burning