Climate Change

Concepts Instructor Prep Student Protocol

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Global climate change is a fervently discussed topic in the news, and scientists agree that the Earth's climate is changing. But before going into what causes climate change and how scientists study it, let's clarify a few terms. The word climate is often used interchangeably with weather, but there is a difference.

Weather describes the atmospheric conditions, such as temperature, in a region over a short period of time, like a day. Climate, however, records the same conditions for the same region but over an extended period, average annual temperature for example. Global climate refers to the same variable analyzed and compiled across the entire planet. If you look at the data for average global temperature since 1880, you will see that it has been on the rise, and this is what people refer to as global warming.

One major contributor to global warming is the greenhouse effect caused by greenhouse gases, such as carbon dioxide, water vapor, ozone, and methane. These gases got their collective name because they form a layer around the Earth that is similar to the glass shield of a greenhouse. Just like the greenhouse, this layer of gas allows the Sun's rays to penetrate and then traps them, letting only a portion of the reflected rays escape back into the atmosphere and leading to a rise in temperature near the Earth's surface. Some cover of greenhouse gases is essential to ensure that the Earth's temperature stays habitable, but human activity, such as fossil fuel burning, have led to the concentration of some of these gases like CO2, which has risen above optimal levels, fueling global warming.

One major impact of this climate warming is the melting of glacial ice, which in turn results in sea level rise. This melting is exacerbated due to a phenomenon called the albedo effect. Albedo, derived from the Latin word, “albus”, meaning “white”, refers to the ratio of proportion of reflected to total solar radiation. This value will be close to one for fresh, white snow because it reflects most of the radiation. Bare soil, in contrast, has an albedo of only around 0.2, and open ocean only 0.1, and so these reflect significantly less - and so, as the climate warms, the snow melts, resulting in lower albedo, meaning that the Earth reflects less and retains more of the radiation as heat. This, in turn, causes the snow to melt more, creating a positive feedback loop and rising sea levels.

Another impact of climate change can be seen in species distribution. Species are found across a geographical area known as their range. As the climate warms, the resulting environmental changes, like melting ice caps, can cause a shift or decline in the habitable range of some of the species. Scientists have been studying these range shifts for different organisms in response to a variety of environmental variables. Using these data, they can model future changes in climate patterns and predict the likely fate of a species.

In this lab, you will assess greenhouse effects on an artificial microclimate, compare melting ice in different conditions, and study historical species' range shifts following environmental change.

Print Procedure Steps

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Melting Land and Sea Ice
- NOTE: This activity is a simulation of land- and sea-ice melting and their effects on water levels.
- First, label one graduated cylinder as 'Sea Ice' and the other graduated cylinder as 'Land Ice.' Hypotheses: the experimental hypothesis might be that the land ice melting will cause the water level to rise more than the melting sea ice. The null hypothesis would be that there will be no difference in the change in water level between the two containers.
- Add 10 ice cubes to the sea ice graduated cylinder, and then fill it to the 300 mL mark with cold water from the faucet.
- Record the initial water level in centimeters in Table 2.
- Fill the land ice graduated cylinder to the 300 mL mark with cold water from the faucet.
- Place the styrofoam piece on top of the water.
- Add 10 ice cubes to the graduated cylinder and record the initial water level in Table 2.
- Allow 30 minutes for the ice to melt.
- Once the ice is melted, record the final water level in both the sea ice and land ice graduated cylinders in the table.
- Now, calculate the change in water level in each graduated cylinder by subtracting the initial measurement from the final water level values. Change in water level = final water level - initial water level
- Record this value in Table 2.
- Submit the change in water level data for each container to the class instructor to be pooled with the rest of the class data in Table 4.
Greenhouse Gas Effects
- NOTE: This activity is a intended to simulate the effect of greenhouse gases on the Earth, by investigating the different greenhouse properties of a covered container versus an open container. HYPOTHESES: The experimental hypothesis could be that the covered container will reach a higher temperature than the uncovered container. The null hypothesis may be that there will be no difference between the temperature in the covered versus uncovered container.
- First, tape thermometers to the insides of both graduated cylinders, facing outward so that the numbers can be seen through the plastic. Make sure the thermometers are at the same level.
- Label the first graduated cylinder 'Open,' and the second cylinder 'Closed.'
- Place plastic wrap over the top of the closed cylinder and secure it firmly with tape or rubber bands. NOTE: Each student group should use the same method to secure the plastic wrap.
- Record the initial temperatures of the cylinders in Table 3.
- Set both graduated cylinders out in the sun or under a heat lamp for 30 minutes.
- Once 30 minutes has passed, record the final temperatures of each container in Table 3.
- Calculate the change in temperature by subtracting the initial temperature from the final temperature. Change in temperature = final temperature - initial temperature
- Record the resulting value in Table 3.
- Submit the change in temperature data for each container to the class instructor to be pooled with the rest of the class data in Table 5.
Species Range Shifts
- NOTE: In this activity, you will observe historic glaciation in North America and Pleistocene and modern-day species ranges for a rodent species. Then, you will develop hypotheses to explain any observed shifts in the species range. Hypotheses: The alternative hypothesis might be that the species range of your assigned rodent species will have expanded Northward between the Pleistocene and the modern-day maps. The null hypothesis would be that the species range will not change between the time periods.
- To explore species range shifts, obtain a species assigned by the instructor with its Pleistocene distribution. NOTE: Pleistocene = 21,800 to 15,600 years ago.
- Use the provided figure which depicts historic glaciation in North America to develop a hypothesis about how species may shift their ranges between the Pleistocene and modern-day climates.
- Now, review your assigned species range distribution for the modern-day era and compare it to the Pleistocene distribution.
- Record your general observations on species range shifts seen in any direction in Table 7 and record your hypotheses for these observations.
Data Analysis
- Collect a copy of the compiled class data for the average change in temperature and water level from the instructor, tallied in Table 4 and Table Five respectively.
- For the land versus sea ice activity data, type the data range or highlight cells to insert the values into the parentheses of the average command (=AVERAGE(X:X)).
- Now type or highlight the data range into the parentheses of the standard deviation command (=STDEV(X:X)).
- Plot the mean and standard deviation for each treatment as a bar chart.
- Then, calculate and plot the mean and standard deviation for each treatment from activity two in the same manner, and generate a bar chart.
- Perform a t-Test on the sea and land ice data by first starting the analysis tool pack by clicking on “data”, and then “data analysis”.
- Select “t-Test, paired two sample for means” from the drop-down menu, and click “OK”.
- Click on the upward facing arrow next to variable one and select the data for the land ice by clicking on the first data point and dragging the cursor to the last data point in the column.
- Then click the arrow next to variable two and select the data for the sea ice.
- Select a place for the output and click “OK”.
- Repeat these steps for the class data from the greenhouse gases activity.
- Record the p-values and direction of any significance for both activities in the appropriate table.
- For the species range activity, record whether the species appeared to undergo a range shift, which direction it was in, and why this may be.
Results
- To analyze your data, examine the data plot from the melting sea ice activity, and note whether land or sea ice melting resulted in a greater water level rise.
- Next examine the results of greenhouse gas effects activity and note whether the data showed any differences in the temperature in the covered container, as compared to the open container. If you did notice difference, consider what the addition of the plastic wrap can be compared to, environmentally speaking.
- Finally, in the species range activity, note whether your species underwent a Northward range shift and discuss this finding with your classmates. If your species did not undergo any noticeable range shift, or shifted in a direction other than Northwards, explain why you think this might be the case. NOTE: It is important to remember that these data sets are small representations and that historical data cannot truly be complete, but they do provide a cursory examination into how species ranges can change under a warming climate.