The Copenhagen Diagnosis is a big report made by many very smart scientists from all around the world. They wanted to explain to the grown-ups in charge of our planet that climate change is a really big problem that we need to fix before it gets worse.
Think of the Earth like a big balloon that we all live on. When we make too much pollution, like when we drive cars or cut down trees, it makes the balloon get really hot and could even pop! This would be very bad because lots of people and animals could get hurt.
The Copenhagen Diagnosis talks about lots of things that we can do to help stop the Earth from getting too hot. Like using more clean energy from the sun, wind, and water instead of dirty energy like oil and coal. They also talk about how people need to change the way they do things, like using less plastic and recycling more.
The report is really important because it gives grown-ups ideas on what they can do to help the Earth, so kids like you can grow up in a healthy and happy world.