Climate change is when the amount of heat in our atmosphere (the air around us) changes over time. When the heat in our atmosphere gets too high, bad things can happen. For example, it could make our weather more extreme, like more hurricanes or bigger floods. It could also make animals sick, make the ground dry and plants die, and make the oceans too warm for sea animals to live in. All of these things make it harder to grow food and keep people healthy. We need to work together to reduce climate change, so things don't get worse.