The United Nations is a group of countries that work together to help keep the world fair and peaceful. Every year they have a big meeting where they talk about important things that affect the whole world. One time, in 2009, they talked about something called "climate change."
Climate change is when the world is getting warmer because of lots of things we do, like driving cars and building factories. When the world gets warmer, it can cause problems like floods, droughts, and the disappearance of some animals.
At the meeting in 2009, leaders from all around the world came together to try to find ways to stop climate change from getting worse. They talked about how to use less energy, like turning off lights and planting more trees to help clean the air. They also talked about making new rules to make sure people and companies are doing their part to help the environment.
Even though it was a very important meeting, it was hard for everyone to agree on what to do. Some countries didn't want to make any changes because it might cost them money or they didn't think it was a big deal. Other countries thought it was really important and wanted everyone to work together to help the planet.
In the end, they made a big agreement called the "Copenhagen Accord." It wasn't perfect, but it was a start. It said that countries would work together to cut down on the things that cause climate change and help each other out if there were any big problems.
So even though it was a big challenge, the people at the United Nations worked hard to try to make the world a better place by fighting climate change.