Brodie Baile Global Climate Change Lab
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School
Colorado State University, Fort Collins *
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Course
121
Subject
Geology
Date
Apr 3, 2024
Type
Pages
10
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GEOL 121 Name_________________________________ Lab Section ____________ This module was initially developed by O’Reilly, C.M., D.C. Richardson, and R.D. Gougis. 15 March 2017. Project EDDIE: Climate Change. Project EDDIE Module 8, Version 1. http://cemast.illinoisstate.edu/data-for-students/modules/climate-
change.shtml
. Module development was supported by NSF DEB 1245707. GLOBAL CLIMATE CHANGE LAB Student Handout Learning objectives: •
To analyze global temperature data to see if Earth’s average global temperatures are really increasing •
To analyze CO
2
data to see if atmospheric levels are really increasing •
To correlate CO
2
data with global temperature to see if there is a relationship •
To compare current trends with rates of change during pre-historic periods using ice core data •
To interpret what these results mean for understanding current climate change Why this matters: Current climate change is affecting many aspects of the environment, with socio-
economic consequences. For example, a warmer climate can allow new diseases to be introduced and persist (e.g. West Nile became established in the United States after an unusually warm winter allowed the mosquitos that carry the virus to survive and spread). We are concerned not only with the actual temperature, but also with the rate that the temperature changes. Very rapid changes make it more difficult for humans to adapt and more likely that other species cannot adapt and will go extinct. Activity A: How much are temperature and atmospheric CO
2
changing? Changes in air temperature -
Scientists from the Goddard Institute for Space Studies, NASA, compiled temperature datasets from weather stations all over the world to create the dataset you are going to be working with today to answer the question: Is earth “warming”? The data you will use are from years 1880-2022. 1.
Before you conduct your analysis, you should first make your predictions. What slope would indicate a warming Earth? What slope would indicate Earth’s average global temperature was not changing? What slope would indicate a cooling Earth? Sketch lines in the axes below to show what the expected slopes would be in these different scenarios. cooling warming no change o
C
o
C
o
C
time time time
GEOL 121 Global Climate Change Lab 2 Getting the air temperature data: These data are compiled by the Goddard Institute for Space Studies, NASA, and are made available at https://data.giss.nasa.gov/gistemp/
. For this lab, the data has been organized into an Excel spreadsheet for you, which you can find on the lab Canvas page. Open up the Global Temperature dataset by selecting the correct tab at the bottom of the spreadsheet.
2.
Examine Graph A.
Describe in words how global temperature has changed between 1880 and 2022. exponentially increasing 3.
We will now determine the rate of temperature change. Determining rates of change graphically is straightforward. The average rate of change is just the change in temperature divided by the change in time, or change in y divided by the change in x, or the slope of a line that fits through the data. Excel can calculate the slope of a line very easily. In Graph B
, a linear trendline has been added to the global temperature data (
black dashed line
). The equation for the trendline is also shown (outlined in black). The equation is written in the form y = mx + b
, where m
is the slope and b
is the intercept. Another name for the slope (
m
) is the rate of change. The R-squared (R
2
) is a statistic resulting from a linear regression analysis, which is the statistical name for what we just did by adding a trendline. It describes the proportion of variation in the dependent variable explained by the independent variable. When R
2
~1, the data form a perfectly straight line. As the data become more scattered from the line, R
2
decreases toward 0. Higher R-squared values indicate a stronger relationship between the two variables. Record the R
2
value down with your slope. a.
Equation for the line: y=.0077x-15.053 b.
R
2
= .763 c.
Rate of air temperature change (include units): .0077 c/year d.
Given your analysis, is Earth warming? How do you know? It is warming because of the positive rate of air temperature change.
GEOL 121 Global Climate Change Lab 3 4. Many scientists suggest that drastic changes in global temperature began in the mid-1900s when fossil-fuel-powered transportation became a mainstay for most families. We can test this hypothesis by adjusting the trendline so that it only looks at the most recent decades, after personal transportation became common. The red solid line
on Graph B
only includes data from 1965-2022. Record the values for the red solid trendline below. a.
Equation for the line: .0183x-36.109 b.
R
2
= .9194 c.
Rate of air temperature change (include units): .0183 c/year d.
Compare the slopes of these two lines (1880 through 2022 (black) versus 1965 through 2022 (red)). Does your analyses support the hypothesis that the rate of global average temperature is greater in recent decades? It supports the hypothesis because the slope as the years pass gets steeper. Changes in atmospheric CO
2
- In 1958, Dr. Charles David Keeling (1928-2005), who was a scientist at Scripps Institute of Oceanography, began collecting data on atmospheric CO
2
concentration at the Mauna Loa Observatory located in Hawaii. This dataset is what allowed us to understand the degree to which climate change is human-caused through our burning of fossil fuels and release of CO
2
into the atmosphere. Due to his scientific achievements, Dr. Keeling was awarded the National Medal of Science by President George W. Bush in 2002. This is the highest award for lifetime scientific achievement that can be granted in the U.S. Today, you get to analyze this same dataset, except that you have more data than was available to Dr. Keeling and his colleagues, because your dataset extends up to current time. Getting the atmospheric CO
2
data: The longest measurements of atmospheric CO
2
concentrations have been done in Mauna Loa, Hawaii. The simplest way to access the data is directly from the Mauna Loa page. http://www.esrl.noaa.gov/gmd/ccgg/trends/ For this lab, the data has been organized into an Excel spreadsheet for you, which you can find on the lab Canvas page. Open up the dataset by selecting the Mauna Loa CO
2
tab at the bottom of the spreadsheet.
GEOL 121 Global Climate Change Lab 4 1.
Examine Graph C. Describe in words how atmospheric CO
2 has changed between 1959 and 2022. It increased 2.
The black dashed line on Graph C
is a linear trendline applied to the CO
2
data. Record the equation and R
2
for this trendline below. Determine the current rate of change for atmospheric CO
2
data, as you did for air temperatures. a.
Equation for the line: 1.6244x-2875.2 b.
R
2
= .9818 c.
Rate of air CO
2
change (include units): 1.6244 ppm/year d.
Based on your analysis, has atmospheric CO
2
concentration increased? How confident are you in these results? Yes, the slope is positive, CO2 levels increased. I'm confident.
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