Winter without snow, melting glaciers, and increasingly hotter summers: Our Earth is sweating. The culprit is humanity, it is us. Climate killer CO2 and other greenhouse gases are heating up our atmosphere - with an uncertain outcome. This thematic issue provides students with fundamental knowledge about the climate and the warming of our planet. Complex relationships are explained simply and vividly, and students can test them through numerous experiments. For example, the children simulate the rise in sea levels and the greenhouse effect using simple materials. The worksheets encourage students throughout the issue to take active action: You too can protect the climate!.