My theory: The forces of Line Must Go Up are going to keep winning. Mitigating the impact of climate change will be part of Line Goes Up. Whether it will be cheaper or more expensive than avoiding it in the first place will remain to be seen (but won't really matter in the end), but we will be facing whatever impacts we will be facing, and we will face them, and we will deal with them.
If you have any doubt, look at how the Netherlands dealt with storm surge.
If you have any doubt, look at how the Netherlands dealt with storm surge.