GEOSCI 106 Lab 10_ Climate change- MARCH
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University of Wisconsin, Madison *
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Course
106
Subject
Geology
Date
Dec 6, 2023
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5
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GEOSCI/ENVIR ST 106: Environmental Geology
Lab 10: Greenhouse gases and climate change
Assignment overview:
Modern climate change has been largely generated by changes in greenhouse gas
concentrations. In this lab, you will quantify the relative effects of different greenhouse gases on climate,
and you will explore the spatial and temporal patterns of climate change observed in the recent past.
Instructions:
Fill out each red highlighted field (_________) according to each question’s instructions.
Submission:
To submit the assignment on Canvas, use the following steps:
1.
In Google Docs, generate a PDF: File → Download as → PDF Document
2.
In Google Docs, use Share → Get Shareable Link, and copy the link address
3.
In Canvas, upload your PDF to the assignment.
4.
In Canvas, paste the link address to your Google Doc in the assignment comments.
Potentially useful things:
This lab will require doing some calculations involving multiplication and
division. To arrive at the right answers, it will be helpful to carefully keep track of the units in your
calculations. To help with this, you may find the following numerical conversions useful. It will also be
useful to review the information on these topics that was covered in lecture.
1°C = 1.8°F
1 ppm = 1 part per million = 10
-6
= 0.000001
1 ppb = 1 part per billion = 10
-9
= 0.000000001
1 ppt = 1 part per trillion = 10
-12
= 0.000000000001
1
Figure 1.
Anomalies in July global average temperature from 1880 to 2019. Here, the y-axis
indicates the difference between each year’s global average July temperature and the 20
th
century’s average July global temperature. For example, a value of 0.2°C in a given year
indicates that July that year was 0.2°C hotter than the 20
th
century average. See the following link
for a zoomable version of this figure that can help you identify each year’s anomaly.
https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature
1. (a) Follow the link in the caption to Figure 1. In the article the link takes you to, zoom in on the
data in the first figure, which shows the same data as Figure 1 here in the lab. Scroll your cursor over
the bars in this graph to reveal a text box with the temperature anomaly. Which year was coldest?
Which year was hottest? How much colder and how much hotter were those years than the 20
th
century average? (2 points)
1904 was the coldest at -0.5 degrees and 2016 was the hottest at 1.0 degree above normal. _________
(b) What are the five hottest years in this record? (1 points)
_2015, 2016, 2017, 2018, 2019________
(c) When was the most recent year temperatures were lower than the 20
th
century average? (1 point)
_2000________
2
Figure 2.
Rate of change in temperature between 1990 and 2019. Here, the units are degrees
Fahrenheit per decade.
2. (a) Examine the map in Figure 2. Based on these data, what part of Earth warmed the most
between 1990 and 2019, and at approximately what rate? (1 point)
The north pole warmed at about a rate of 1 degree per decade._________
(b) What geographic region cooled the most over this time, and at approximately what rate? (1 point)
The ocean at the southernmost part of South America cooled at a rate of about -.05 degrees per
decade._________
(c) Where did more warming occur: over land or over the ocean? (1 point)
Ocean_________
3
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(d) Using the data in Figure 1, calculate the rate of change in global average July temperature.
Compute this as the change in temperature between 1990 and 2019 divided by the number of years
between 1990 and 2019. Include the units in your answer. (1 point)
_1.0-.04/29= 0.02 degrees per year________
(e) Which was faster: the maximum regional warming rate in Figure 2, or the global average warming
rate? Calculate the ratio between these two values to determine how many times faster one was than
the other. In your calculation of this ratio, be sure to use the same units in the numerator and
denominator. (2 points)
_The global warming rate was faster at a rate of 32.01 degree F per decade________
Table 1.
Global warming potentials of different greenhouse gases and their atmospheric
concentrations. (Concentrations are listed in parts per million (ppm), parts per billion (ppb), or
parts per trillion (ppt). See Unit Conversions on the lab’s first page.) These numbers quantify the
capacity of a certain amount of a gas to induce a certain amount of warming over 100 years,
relative to the warming induced by the same amount of carbon dioxide over the same time.
3. (a) Some greenhouse gases are more efficient at absorbing Earth’s emitted radiation than others, which
means that they generate more warming per molecule. This amount of warming each type of gas
generates is known as its global warming potential. Table 1 shows the global warming potential of
several greenhouse gases relative to that of carbon dioxide over a 100-year interval; that is, each gas’s
warming potential has been scaled to that of carbon dioxide. For example, one molecule of methane
warms the Earth about 34 times more than one molecule of carbon dioxide does. By definition, under this
scaling, the global warming potential of carbon dioxide is 1.
In the atmosphere, the amount of warming accomplished by a given gas depends on its global warming
potential as well as how much of that gas is in the atmosphere—i.e., its concentration. For a given gas,
this can be calculated as the product of its global warming potential and its concentration. Use the
4
Gas
Global warming potential
Concentration
Carbon dioxide (CO
2
)
1
415 ppm
CFC-11
5350
225 ppt
Methane (CH
4
)
34
1850 ppb
Nitrous oxide (N
2
O)
298
330 ppb
information in Table 1 to calculate the ratio of the warming produced by carbon dioxide to the produced
by each of the other gases. (3 points)
Ratio of warming by CO
2
to warming by CH
4
: _1/34________
Ratio of warming by CO
2
to warming by N
2
O: _1/298________
Ratio of warming by CO
2
to warming by CFC-11: _1/5350________
(b) Based on your answer to part (a), list the four gases in Table 1 in order from the largest influence on
Earth’s climate to the smallest. (1 point)
_CFC-11, N20, CH4, CO2________
(c) Global climate models project that carbon dioxide concentrations may reach 600-1000 ppm by the
year 2100. How much warming would that much carbon dioxide generate relative to the amount of
warming currently generated by carbon dioxide? Express the upper and lower bounds on this range as the
ratio between the amount of warming that this carbon dioxide will produce to the amount of warming
carbon dioxide currently produces. (2 points)
_1.45< x< 2.4________
4. (a) Read the news article, “Trees on the Move”
(
https://www.npr.org/sections/krulwich/2014/02/18/279189378/trees-on-the-move-as-temperature-zones-
shift-3-8-feet-a-day
). Which types of plants and animals are most likely to be immediately impacted by
climate change? List three characteristics that make them more susceptible to climate change. (3 points)
_Snails, Worms and Beetles because they can’t move as far as fast as other animals.________
(b) Looking beyond the
global
headline number of 3.8 feet of climate zone movement per day, what
local
factors may affect the average movement of climate zones? List two factors. (2 points)
_Latitude and elevation.________
5