Grade 10 Academic Science – Climate Change
Greenhouse Gases – Changing the Climate
Section 9.4 Pages 384-389
Greenhouse Gases are a natural part of Earth’s atmosphere. Yet, Greenhouse Gas levels have
increased significantly in the past 2000 years (see Figure 1). These increases are attributed mainly to
human activities such as burning fossil fuels. The scientific term for “resulting from human influence” is
ANTHROPOGENIC.
Figure 1. Concentration of Greenhouse Gases in Earth’s Atmosphere over the past 2000 years.
The principle greenhouse gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), water
vapour (H2O) and chlorofluorocarbons (CFC). The most significant greenhouse gas produced by
human activity is CO2. Table 1 shows the change in atmospheric CO2 between 1959 and 2009.
Task

Calculate the percent change in CO2 concentrations in the atmosphere for each year since 1959
using 1959 as the base (...or starting...) year.
Table 1. Atmospheric CO2 Concentrations at Hawaii between 1959 and 2009
Year
Atmospheric CO2 Concentration
(ppm)
Percent Change since 1959
1959
315.98
------
1969
324.62
1979
336.78
1989
352.90
1999
368.14
2009
387.35
Source: EPA. 2010. Atmospheric Concentrations of Greenhouse Gases. (Online).
http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewInd&lv=list.listbyalpha&r=231323&subt
op=342
Did you know?
 The number of atoms of carbon stored in Earth’s plants, soil and dead organic matter is greater
than the number of atoms of carbon present as CO2 in the atmosphere
As you know, global temperatures are increasing as the concentrations of atmospheric Greenhouse
Gases are increasing. Table 2 shows CO2 concentrations from 400,000 years ago to present is
determined from ice cores from the Antarctic.
Table 2. Atmospheric CO2 Concentrations and Air Temperature Variation from 400,000 to present
measured in ice cores from the Antarctic.
Year before
Atmospheric CO2 Concentration
Air Temperature Variation
present
(ppm)
(OC)
400,000
279.1
1.0
375,000
239.1
-4.5
350,000
186.2
-7.7
325,000
255.7
3.5
300,000
257.2
-1.7
275,000
228.0
-3.5
250,000
205.7
-6.2
225,000
279.0
2.0
200,000
251.0
-1.7
175,000
190.1
-7.3
150,000
200.6
-7.1
125,000
275.4
3.2
100,000
228.2
-2.0
75,000
217.1
-5.0
50,000
190.4
-6.0
25,000
191.7
-8.2
0
387.35
3.5
Source: EPA. 2010. Atmospheric Concentrations of Greenhouse Gases. (Online).
http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewInd&lv=list.listbyalpha&r=231323&subt
op=342
Task





Graph the CO2 Concentrations and Air Temperature Variations in ice cores over time.
Contrast Year 0 with other periods of high CO2 concentrations. What do you observe?
What is happening to CO2 concentrations and global temperatures at Time 0 (now)?
Summarize you observations regarding the trend in CO2 and air temperature, and any correlation
between the two variables (i.e., How the variables change at the same time).
Do your graphs prove that CO2 concentrations cause global temperatures to change...specifically
to rise? Explain. HINT: Recall the connection between the Greenhouse Effect and Earth’s
temperature.
ANTHROPOGENIC GREENHOUSE EFFECT is the increase in the amount of lower-energy infrared
radiation trapped by the atmosphere due to human activities which is leading to an increase in Earth’s
average global temperature.
 Humans are ENHANCING the Greenhouse Effect
 As human release more greenhouse gases, Earth’s energy balance changes (i.e., more thermal
energy is trapped inside the atmosphere, raising global temperature beyond “normal”).
FEEDBACK LOOP
(see also Section 8.10 in your textbook).
You know an increase in
greenhouse gases in the
atmosphere increases
temperature.
At the same time, the
temperature increase
increases the concentrations
of greenhouse gases in the
atmosphere.
Permafrost is a carbon sink.
As temperature increases, the
permafrost thaws. This action
releases the greenhouse
gases contained in the
permafrost. The concentration
of greenhouse gases in the
atmosphere increase further,
which in turn, increases
temperature.
This is called a Positive Feedback Loop.
NOTE: The ocean is a carbon sink that stores vast amounts of carbon. Much of the carbon is stored as
dissolved CO2 and carbonic acid.
Task

Describe and explain the Feedback Loop that will occur as ocean temperature rise.
HOMEWORK / PRACTICE
 Page 389 Questions 1-6