Unmanned aerial vehicles (UAVs) can now measure CO2 levels accurately using a new portable system. The system, weighing just over 1 kg, can be attached to small UAVs for autonomous in-flight measurements. Lab tests show it can measure CO2 changes with high precision. Field tests against a reference instrument confirm its accuracy. The system's fast response allows for real-time monitoring of CO2 emissions and their distribution. This new technology opens up possibilities for using UAVs to study atmospheric gases.