Read this piece in the NY Times by Justin Gillis. The piece is really strong in terms of its discussion of climate science but amazingly weak in terms of its discussion of social science. He returns to the theme of rising sea levels and what this means for coastal areas. Without any serious discussion, he jumps to claim that tens of millions of people are at risk. He appears to embrace a science fiction view that the water rises like a Tsunami and catches millions of unprepared people. In the real world, what happens as sea levels rise? Rational urbanites foresee this trend and retreat and move to higher ground. There is a lot of land on higher ground and we will rebuild our cities there. This will create jobs and "economic stimulus". We are always rebuilding our cities. It is possible that we will live at higher population density but cities such as Hong Kong, NYC and Singapore have shown that there can be high quality of life in dense cities.
Permit me to repeat, there are scenarios under which Gillis is correct and a catastrophe is approaching but you must embrace an extreme view of myopia at the individual level and place based politicians doing everything in their power to keep coastal residents from retreating in the name of attracting more Federal FEMA resources for their jurisdiction.
Developing country cities built along coastal areas are at the greatest risk but again for those who want to help such nations adapt don't forget the "miracle" of Japan, China and South Korea. Economic growth offers the best strategy to adapt as it gives the people of the nation the resources to invest in their own coping strategies.