Department of Geography and Environmental Studies
GG101 Introduction to Physical Geography
Lab 6: Environmental Change with focus on Climate
Tasks and Questions
Figure 1 in the Lab 6 background reading shows the global mean annual temperature record from 1880 to 2019 presented as departures from the 1951-80 mean. Figure 3 shows the change in Canada over the period 1948 to 2019 expressed as departures over the period 1961-90. Figure 3 was from the Climate Trends and Variations Bulletin (Annual Report 2019) published by Environment Canada. The graph below has been generated from that same data and adjusted so the baseline period is also 1951-80. The years plotted are 1950 to 2019. The annual values are shown in grey, the red line is a 5 year running average and the blue line is a linear trend fit over the period 1970 to 2019.
Compare Figure 1 from the background reading with the graph above. From Figure 1, consider the period only from 1950 to 2019. Both records show that temperatures in the 1950s and 1960s were largely unchanged (flat). By the mid-1970’s the temperatures began to increase.
Question 1 (2 marks)
For the period from 1970 to 2019.
- Estimate the magnitude of the temperature change that occurred Globally and in Canada, present your estimates as numeric values over that interval.
- Comment on the year to year variability (variation) in the two records, which record has more variability.
Spatial Pattern over the Period 2000-2019
In the Climate Atlas of Canada, a base period of 1976 to 2005 is used to capture ‘current conditions’.
Go the GISS global mapping site described on pages 2, 3 and 4 in the background reading. Set the Data Sources using the parameters shown in the background reading (they are the default data sources). The Map Type will be Anomalies. For the Base Period use 1976 to 2005. For the Time Interval use 2000 to 2019 (20 year time interval). We will examine mapping output that shows the spatial variation in global temperature over the period 2002 to 2019 (relative to 1976 to 2005).
For the Mean Period use:
- Annual (Dec-Nov)
- NH Winter (Dec-Feb)
- NH Spring (Mar-May)
- NH Summer (Jun-Aug)
- NH Fall (Sep-Nov)
Task 2 (5 marks)
Examine the five maps you have created that show the spatial distributions of the changes in mean
Annual, Winter, Spring, Summer, and Fall temperatures over the period 2000 to 2019. Complete Table 1 by identifying the global areas that are experiencing the most substantial warming and cooling for the selected time periods. You may identify global areas in a number of ways, such as latitudinal zone (e.g., high latitude land areas of North America), segment of a continent (e.g., northeastern Africa), country (e.g., Chile and Peru), or segment of an ocean (e.g., Arctic Ocean north of Siberia).
Question 2 (1 mark)
What season has shown the most significant change in temperature over the period 2000 to 2019?
Question 3 (1 mark)
Overall, what latitudinal zone has experienced the greatest warming since 2000?
Table 1. Spatial patterns in warming and cooling over the period 2000 to 2019.
Areas of Highest Warming
The data in the maps from GISS show us the magnitude and spatial pattern of warming that has occurred over the last 20 years. We will use results from a General Circulation Model (GCM) from the same organization to examine the distribution of changes to mean annual temperature that would occur if the concentration of greenhouse gases in the atmosphere increased to the equivalent of 520 ppm CO2 and a new planetary energy balance were to be established. The CGM is called ROCKE-3D and the URL is in the background document. Examine the global pattern of surface temperature change that is projected under a scenario of a doubling of CO2 (2X CO2) as compared to pre-industrial CO2 levels. Repeat the process for a four times CO2 (4X CO2) scenario. For these two maps use the Variable called surface temperature.
Question 4 (1 mark)
What is the average warming that would occur for the globe as a whole for the two scenarios?
2X CO2 :
4X CO2 :
We will now use the ROCKE-3D model to examine how a series of variable may change as we move to a higher CO2 world. For these analyses we will use two time periods, they are the Pre-Industrial and the 4X CO2 time frame. We will examine three Variables, they are:
- sea ice fraction (%)
- planetary albedo (%)
- cloud cover (%)
For each of these variables examine the results from the pre-industrial model and the 4X CO2 model.
Question 5 (3 marks)
Describe the overall changes (global) that occur when we compare the pre-industrial to the 4X CO2 model for these three variables.
Question 6 (1 mark)
Why is a loss of sea ice in polar regions associated with a lower albedo in the same regions.
Task 5 (5 marks)
In this section we will look at climate changes at the local scale that are projected for the Toronto area under two different scenarios. Go to the Climate Atlas of Canada interactive mapping website. In the Climate Atlas interactive map, examine the Annual, Winter, Spring, Summer, and Fall mean temperatures for the Toronto location. Record the average values for each of the above variables for 1976-2005, and for the projected time periods 2021-2050 and 2051-2080 under the Less Climate Change and More Climate Change scenarios. Enter the data into Table 2.
Table 2. Average temperature values for Toronto, with projected average temperatures under the Less and More Climate Change scenarios.
Examine the graphing output for the above variables for the two scenarios (low and high amounts of climate change). The high amount of climate change corresponds to a high emission scenario, this is similar to the pathway that we are currently following. The magnitude of change for each of the above variables is larger for the higher emission case. Figure 11.27 in your textbook shows the global projections of mean temperature change for these same two scenarios, they are called RCP8.5 and RCP4.5 for the high and low emissions cases. Refer to the graphs from the Climate Atlas that you have just examined and Figure 11.27.
Question 7 (2 marks)
Compare the projected temperature changes for the Toronto area that will occur under the two scenarios. Comment on the seasonal pattern and on the difference between the two scenarios.
Question 8 (4 marks)
Return to Climate Atlas mapping site, zoom down to the Toronto area. There are several variables that are listed under the Heading “Hot Weather”. Using the higher emission scenario for the two projected time periods examine the variables: (i) Very Hot Days, (ii) Tropical Nights, (iii) Number of Heat Waves, and (iv) Average Length of Heat Waves. What do the projections show? Using the resources available from the Climate Atlas site comment on why these projected changes are of particular concern for urban areas in Canada.