Well, kiddo, the Environmental Modification Convention is a very important agreement that different countries made to protect the planet from harmful changes in the environment that humans might cause.
It's kind of like a big promise that all the countries in the world made to each other, to try and prevent any actions that might cause natural disasters, like floods or droughts, or that might harm animals, plants, or people.
For example, one way people might change the environment is by creating huge dams that stop the flow of rivers or build things that release pollutants into the air – such as factories or cars. These actions can have really bad consequences for other animals or people living in the region.
That’s why the convention agreement is designed to prevent any of these harmful consequences all across the world, for the good of everyone on earth. It helps countries work together to keep earth a happy and healthy place for all living beings.