Optimal strategies to cope with climate change depend on the pace of change

The researchers calculated the return on investment for each scenario using the discount rate—a measure that investors use to value future income. A high discount rate means investors don’t value the future cost as much as if they have a low discount rate.

It makes more sense to build near the coast if buildings don’t last very long, because investors are focused on short-term return, and sea level is rising slowly. Durable buildings, low discount rates, and rapid rates of sea level rise would point to building farther from the shoreline.

Of course, ignoring future sea-level rise is a recipe for failure. A buffer zone approach based on a single amount of sea-level rise fails to make productive use of valuable coastal land. The dike approach provides only a temporary hold, but even though they provide no long-lasting solution, they could make sense if the dikes could be made cheaply enough.

While the researchers focused on sea-level rise, they believe that consideration of rates of climate change and sea-level rise should be taken into account in other areas of adaption, including adaptation of agriculture, buildings, and other sectors. The authors point out that their study represents a first step in understanding practical approaches to adaptation, and that more research is needed to understand and manage the response of both human and natural systems to increased rates of change.

Ken Caldeira, of Carnegie Science’s Department of Global Ecology, said “Future research on adaptation strategy needs to consider how economic incentives interact with real political systems, so that we might produce better outcomes. Unfortunately, as we have seen after Hurricane Katrina and in other flooding, if politically powerful people are flooded, they can sometimes get the rest of society to pay for the damage. This can set up perverse incentives and result in people building where they should not build, or putting dikes where they make no sense. Developing good policy means taking into consideration both physical and human dimensions of the problem.”

Caldeira continued, “I used to live in New Jersey, and there was a river that flooded all the time. Eventually, they turned much of the flood plain into a park. Then, when the river flooded, it was no big deal, and the rest of the year, people could enjoy the park. Future adaptation strategy needs to be more like this, where we think about what the best use of land is, and don’t try to fit everything into a ‘one size fits all’ policy.”

— Read more in Soheil Shayegh et al., “Adapting to rates versus amounts of climate change: a case of adaptation to sea-level rise,” Environmental Research Letters 11, no. 10 (4 October 2016)