Data Literacy Project
Thinking of summer? Perhaps not in the Texas heat…
Background: Last week, the National Climate Assesment report was released by the U.S. Global
Change Research Program. The report compiles the most recent scientific data to determine what
patterns and changes are occurring in our climate, and what some of the observed and predicted
effects of these changes are or might be. According to the authors, “A team of more than 300
experts guided by a 60-member Federal Advisory Committee produced the report, which was
extensively reviewed by the public and experts, including federal agencies and a panel of the
National Academy of Sciences.” One of the patterns they analyzed was heat and drought, because
warming and lack of rainfall are likely effects of climate change.
In the graph below, the “Dots show the average summer temperature and total rainfall in Texas
for each year from 1919 to 2012. Red dots illustrate the range of temperatures and rainfall
observed over time.” (If you look at the graph you will see that the red dots form a loose circle
around all of the data, or highlight the range of the two variables) The report producers
highlighted the 2011 data because there were record temperatures and drought that year (large
red dot). They analyzed the data and found that the probability of such an extreme heat-drought
event “has more than doubled as a result of human-induced climate change.”
Data Source: NOAA
NCDC/CICS-NC.
http://nca2014.glo
balchange.gov/high
lights/reportfindings/extremeweather
1. What does each dot represent? (The purpose here is to elicit statements that show that students are
reading the graph correctly. The only specific years that are identified are the ones with red dots. We do not
know any of the other years. But, each dot represents one year’s worth of data on total rainfall and average
temperature (June-August). Ask students to pick one dot and describe that one year “In this year there was a
total rainfall of about 10 inches and the average temperature was about 79 degrees”)
2. Describe what the graph shows about how rainfall and temperature are related. (Purpose
here is to elicit description of what the graph shows. Sample response: Generally, as rainfall increases, the
annual temperature is cooler. When there is very little rainfall, it tends to be during the hotter years.)
3. I interpret the graph to mean…(Purpose here is to elicit an explanation (e.g. of the pattern or variability)
or interpretation of the meaning in terms of the context of the question. Sample response: The year 2011
definitely was both extremely hot and extremely dry. Years 2004 and 2007 were both wet and cooler during
summer. There is some variability, but the pattern seems to be pretty clear: dry years tend to be hotter, and
wet years tend to be cooler.
4.
Is the red dot for 2011 an outlier? And extreme value? What is its contribution to the story
that this graph is telling? (Purpose here is to elicit a discussion about outliers. When do you throw out an
outlier? When is the outlier an important part of the story?)
Note for teachers: Check out this great site from NOAA, which gives teaching resources related to the
National Climate Assessment: http://www.climate.gov/teaching/2014-national-climate-assessmentresources-educators