Environmental archaeology is like being a detective who solves puzzles about things that happened long long time ago by looking at really old things (artifacts) and the environment they were found in. But instead of solving mysteries about people and their lives, environmental archaeologists study nature and the way it's changed over centuries.
Let's say you find a big bone while digging in the ground, but it's not a bone from a dinosaur or a big scary animal you normally see in movies. A "dead" giveaway that it's not from a recent animal is that the bone has turned brown or gray. Environmental archaeologists can tell you what kind of animal it was and what it liked to eat by looking at the marks on the bone. They can even figure out how long ago it lived by measuring the radioactive material in the bone.
It's like a really fun puzzle where you have to figure out what life was like in the past by looking at the pieces of the puzzle you find in the ground, like bones, pollen, and rocks. Environmental archaeology helps us learn about how people and animals lived in the past and how the environment has changed over time. All of this information can help us figure out how the world might change in the future.