First, in what way are you skeptical? That the planet is warming? That humans have anything to do with it? That it’s a result of greenhouse gas emissions? That

First, in what way are you skeptical? That the planet is warming? That humans have anything to do with it? That it’s a result of greenhouse gas emissions? That its effects will be catastrophic? Others have addressed your direct question in more detail: the predictions keep getting worse because a) the original predictions were conservative (“there’s no way it can get that bad”, “there’s no way we won’t begin to react”, etc.), b) we’re getting more data from recent years as the planet does begin to warm and seeing that it’s happening faster than many models predicted so new models have to incorporate this new worrying information, and c) there’s often biases in reporting on top of these other things.