A research collaboration between Victoria University of Wellington and NIWA is working towards a better method for adapting to coastal flooding as sea levels continue to rise due to climate change. The research, published in the journal Environmental Research Letters, outlines a system of “signals” and “triggers” that will warn communities when to act to avoid flooding from sea-level rise.

This new research is part of a project led by Dr. Judy Lawrence from Victoria University of Wellington’s Climate Change Research Institute, with NIWA and Manaaki Whenua Landcare Research.

Rising sea level is already causing more frequent  flooding along many coasts globally and in future will greatly increase the frequency and consequences of flooding and cause saltwater intrusion into groundwater and rivers, geomorphological adjustment of the coastline, and rising groundwater levels.

Rather than use MSL trends or incremental change to develop signals and triggers, the study used increases in the frequency of smaller storm-tides, to signal the future increase in frequency of large storm-tides, which could be tied to an adaptation-threshold.

The study shows how early signals (warnings) and triggers can be designed to initiate adaptive action before coastal flooding reaches an adaptation-threshold beyond which undue harm occurs and costs of adaptation increase.

The authors conclude that an early signal could occur in the 10-year monitoring period starting 2021 meaning that a full strategic assessment, planning and community engagement process needs to begin now with urgency to map out future pathways.

“The next step is to work with councils and communities directly to apply our method,” says Dr. Lawrence. “Housing and infrastructure decisions that are being made now will be impacted by climate change -related coastal flooding, so it is important for communities to be able to consider different coastal flooding scenarios in their planning processes.”

More information: Scott A Stephens et al. Developing signals to trigger adaptation to sea-level rise, Environmental Research Letters (2018). DOI: 10.1088/1748-9326/aadf96 

Journal reference: Environmental Research Letters