We do have economies B for controlled experiments and that data is pretty clear.
The richest countries are those who use the most energy to help them deal with nature.
Effects might happen depending on the temperature but we don't know which or how severe or when or if it will. We don't know how much humans affect it meaning that we don't know if it even make sense to do anything.
Evolution is not scientifically demonstrated. It's a way to interpret the data and observations from biology. It's the model that explains the best, but it's not in itself science just like climate science isn't science in any concise way but rather an interpretation of data.
It's that data which is being discussed and speculated about. We are very far from demonstrating even a fraction of what we speculate.