I'm sure there are aspects of it are not settled, but that is not the same as not knowing anything. We can not predict accurately if it will rain 10 days from n

I'm sure there are aspects of it are not settled, but that is not the same as not knowing anything. We can not predict accurately if it will rain 10 days from now, but we still know it rains every now and then. There are deserts on earth that have been created by humans (Iceland for example, and the "Karst", victims to wooden ship building), and large lakes that are almost gone because of human actions. It also seems obvious that humans pollute water bodies around us to a degree that makes swimming in them or drinking from it impossible, to take up your pissing example.