Chart assignment
Charts to read and discuss
Read each chart, then answer its questions. Every chart shows its source and date; open it for a table of the numbers and the data to download.
Chart 1 of 2 · Climate
How much has the US warmed since 1895?
The interactive chart needs JavaScript. The numbers are on the chart's page.
The contiguous US averaged 54.6°F in 2025. The warmest year since records began in 1895 was 2024, at 55.5°F. Through 2025, the dashed trend line, the straight line that best fits every year, rose about 0.18°F a decade, or 2.3°F since 1895, and warming had sped up to about 0.5°F a decade since 1970. Alaska and Hawaii aren't included.
How to read this chart
Each point is one year's average temperature across the lower 48 states, in degrees Fahrenheit. The axis doesn't start at zero, so a small rise looks steep: read the numbers on the axis, not the height of the line. The dashed line is the trend, the straight line that best fits every year; single years bounce above and below it.
Questions to discuss
- Find the warmest and coolest years on the chart. How many degrees apart are they?
- Why might one year be much cooler than the year before, even while the trend line keeps rising?
- The axis doesn't start at zero here, but bar charts always do. Why is that fair for temperatures but not for bars?
Source: NOAA National Centers for Environmental Information, Climate at a Glance (Public domain (U.S. government work)) · Data as of Dec 31, 2025
Open the chart and its numbersChart 2 of 2 · Road safety
Are U.S. roads getting safer per mile driven?
The interactive chart needs JavaScript. The numbers are on the chart's page.
In 2024 there were 1.19 deaths for every 100 million miles driven, down from 3.35 in 1980. The lowest rate was 1.08 in 2014; it jumped to 1.34 in 2020, when people drove less but deaths rose. Miles driven are the Federal Highway Administration's estimates.
How to read this chart
Each point is the number of people killed in traffic crashes for every 100 million miles Americans drove that year. Dividing by miles driven turns a count into a rate, so years when people drove more or less can be compared fairly.
Questions to discuss
- About what fraction of the 1980 rate is the rate in the latest year?
- In 2020 people drove less, but the rate went up. What could explain that?
- Why is deaths per mile a fairer way to compare years than the total number of deaths?
Source: NHTSA Fatality Analysis Reporting System (FARS) and FHWA Highway Statistics (table VM-2) (Public domain (U.S. government work)) · Data as of Dec 31, 2024
Open the chart and its numbersTeachers: make your own chart assignment, or change this one. Free, no account needed.