Global catastrophic risks are risks that could have major long-term harm on people, animals, or even the whole world. These kind of risks could come from natural disasters like volcanoes, floods, and earthquakes, or from humans doing things like making nuclear bombs or putting too much pollution in the air. Worst case, these types of risks could lead to things like the end of humanity or the end of life on Earth. It's really important for us to think about how to protect ourselves from these possibilities.