I’m not sure what you mean by “the science is settled.”

Science, by definition, isn’t settled. More information will always improve understanding of the past and predictions of the future — especially when it comes to something as complex as the climate.

But we have more than enough information to be confident in some broad conclusions:

1. The climate is warming. Not that each year will be warmer than the last, but that the overall trend is increased global temperatures.
2. Human activity — namely greenhouse gas emissions — is partially responsible.
3. The warming will probably cause various disruptions, including rising sea levels, more intense storms, and droughts. And the likelihood and severity of those disruptions increase the more the planet warms.

Exactly what will happen is uncertain. There’s way too much variance in weather, and uncertainties in predicting a chaotic system, to know for sure.

But the probabilities of serious disruptions that will cause a lot of human and economic damage are high enough that it makes sense to take action to reduce those probabilities.

What actions we should take, and how much of them, is the debate we should be having.