5.4 Why are gloval temperatures changing?

Question 1

what is the atmosphere?

Answer 1

a thin layer of gases extending 100km above the Earth’s surface

Question 2

what is the greenhouse effect?

Answer 2

the energy radiated from the earth’s surface is absorbed by gases in the atmosphere which warms it. these gases stop the infrared radiation from escaping

Question 3

what is global warming?

Answer 3

the gradual increase in the earth’s temperature generally due to the greenhouse effect cause by the increase of greenhouse gases trapped within the atmosphere

Question 4

what does the term global warming potential mean?

Answer 4

the measure of the greenhouse effect caused by the gas relative to the same amount of carbon dioxide over a given time

Question 5

what does CO2 have the largest effect?

Answer 5

it has the longest average lifetime in the troposphere

Question 6

what four processes produce methane?

Answer 6

anaerobic decay of organic matter in waterlogged conditions, decay of waste, cattle and incomplete combustion of fossil fuels

Question 7

what is the effect of methane compared with the effect of carbon dioxide?

Answer 7

a molecule of methane absorbs more infrared radiation than a molecule of carbon dioxide but it does not stay in the atmosphere for as long as carbon dioxide

Question 8

how could methane emissions be reduced?

Answer 8

through cattle waste recycling and using it as biofuel

Question 9

in science, what does the term theory mean?

Answer 9

implies a well-tested and widely accepted idea or principle supported by a great deal of evidence

Question 10

in science, what does the term controversial mean?

Answer 10

alternative points of view about it can be reasonably held

Question 11

why is global warming a controversial issue?

Answer 11

science can’t prove theories, they can only disprove them. there’s incomplete knowledge of how the climate systems work and data sets