Okay kiddo, let me explain it to you in simple terms.
Chappuis absorption is when some gases like carbon dioxide (CO2) and water vapor (H2O) get absorbed by the Earth's surface.
Just like how a sponge absorbs water, the Earth's surface can absorb gas too. And when the gas is absorbed, it becomes a part of the Earth.
This happens naturally and has been going on for a long time, but scientists are now studying it more closely because of climate change.
When the Earth absorbs more CO2 than it can handle, it can cause problems like global warming. That's why we need to be careful and make sure we don't put too much of harmful gases into the air.
Does that make sense to you, little one?