Carbon Detective: free carbon footprint game for Earth Day

What is Carbon Detective?

Eight cases, three suspects each: everyday habits and purchases like a beef dinner, a new phone, a tumble-dried load or a flight. Rank them from the biggest carbon footprint to the smallest, then see the figures to scale and what drives each one. Figures are rounded examples from well-known public estimates.

Carbon Detective is a free Earth Day game about carbon footprints. Each of eight cases puts three suspects side by side, like 1 kg of beef, chicken and lentils, or making a laptop, making a phone and streaming for an hour, and you rank them from the biggest footprint to the smallest.

After each case, bars to scale show rounded example figures in kg of CO2e and a line on what drives each one. The figures come from well-known public estimates, and real numbers vary by country and source, so each case only compares things that differ clearly: the ranking holds whichever source you pick.

At a glance

Category

Seasonal

Difficulty

Medium

Play time

3–5 min

Price

Free, in your browser, sign-up optional

How to play

Meet the suspects

Each case has three habits or purchases, like 1 kg of beef, chicken and lentils.

Rank them

Tap them from the biggest carbon footprint to the smallest. Tap one again to take it back.

Read the reveal

Bars to scale show rounded example figures in kg of CO2e, with what drives each one.

Score

30 points per pair in the right order, +10 for a perfect case. A clue shows one figure for −25.

Scoring

Each case: 30 points per pair of suspects in the right order, plus 10 for a perfect ranking, so 100 per case and 800 per run.

The clue shows one figure for 25 points. Figures are rounded examples from widely published estimates.

What it trains

Carbon footprint basics

What CO2e means and what drives the footprint of food, travel, gadgets and home energy.

A sense of scale

Telling the big items (flights, beef, heating) from the small ones (lights, streaming).

Estimating

Ranking by reasoning about how things are made and used.

Strategy and tips

Think about the making

For gadgets and clothes, most of the footprint comes from making them, not using them.

Cows weigh a lot

Beef, cheese and milk carry methane from cattle, so dairy and beef sit high on food lists.

Watch the flights

One long flight can outweigh months of everyday driving.

Heat is hungry

Heating homes, water and tumble dryers uses far more energy than lights or streaming.

Save the clue

A clue reveals one figure for 25 points. Use it when two suspects look close.

Why play Carbon Detective?

People tend to worry about small things, like a light left on, and miss big ones, like a flight or a beef habit. Knowing the rough size of each footprint helps you put your effort where it counts. Carbon Detective trains that sense of scale with everyday examples, one case at a time.

Frequently asked questions