Climate sensitivity refers to how sensitive our planet is to changes in atmospheric composition, particularly when it comes to greenhouse gases. It measures the response of Earth's climate system to a change in external conditions, such as an increase in carbon dioxide levels due to human activities like burning fossil fuels or deforestation. The sensitivity is determined by how much the global temperature will rise in response to that change in atmospheric composition. A higher level of climate sensitivity means that a smaller amount of greenhouse gases can cause a significant increase in Earth's average temperature, leading to more severe impacts from climate change such as rising sea levels and extreme weather events. Understanding the climate sensitivity is crucial for predicting future changes in our planet’s climate and developing strategies to mitigate or adapt to those changes.