In the fall of 2024, Citizen Math released updated versions of every lesson in our library, plus a few new ones! We know you may have already prepped an earlier version or planned a repeat of last year, so we're continuing to make these earlier versions available through Thursday December 5, 2024.

You can find the new lessons through the regular search, and we hope you love them as much as we do. You can read more about these updates in Our Community.

Click here for the updated version of this lesson!

Scientists estimate that on Halloween 2011 the global population reached 7 billion. But how long did it take humanity to grow to this level, and how large should we expect our population to become?

In this lesson, students will explore how many people the Earth is adding and losing each minute, and use this to build an exponential model for human population growth. They’ll also predict what the world population will be in the future and discuss the environmental consequences of population growth and economic development.

- The global population is growing exponentially
- As the population grows, two other things grow with it: the Gross World Product and the amount of CO2 in the atmosphere.
- The developing world is currently growing more quickly and contributing more to CO2 than is the developed world…but the developed world is disproportionally responsible for getting CO2 levels to where they are now.

- Given two data points, calculate growth rate as a percent
- Build and evaluate an exponential function in a real-world context
- Analyze graphs showing roughly exponential relationships