Rising sea levels - Gregory De Costa

  • Gregory De Costa

One of the biggest impacts of climate change is changing sea levels and the effect this has on freshwater supplies in coastal areas.

Unitec Civil Engineering Senior Lecturer Gregory De Costa has spent the last six years looking at just how much of a problem it could become, focusing his efforts on the low lying coastal city of Wellington which is at risk of “saline intrusion” – saltwater getting into its water aquifer.

“Due to climate change we have either sea level rise or sea level drop, depending on the situation,” says De Costa. “We also have changing weather patterns, and more extreme weather events. My interest is in our water, more specifically groundwater in coastal zones and how these changing weather patterns and rising sea levels affect our water resources, through both surface and groundwater.”

De Costa is part of an international collaboration of civil engineering researchers concentrating on the potential effects of climate change on the Asia Pacific region. Funded by the Asia Pacific Network for Global Change Research (APN-GCR) the group is made up of civil engineers from institutions in India, Japan, Sri Lanka, Indonesia, Australia and New Zealand. All are climate change field researchers, each with their own complementary area of expertise.

His original work on sea level rise was based around the Wellington coastal area of Petone, where he looked at the expected sea level rise and the extreme climate events that could occur in that area and how it could lead to aquifer contamination. “We were able to plot out the area of land that would get inundated, and how much would get inundated for particular scenarios based on different sea level rise data and extreme weather event situations.”

Being able to predict possible flooding in an area like Petone is not the only benefit of this research, De Costa says. It could also help millions of people who live in coastal zones worldwide. “Around the world, the majority of the population lives in coastal zones. Added to this, much of the new industry and development is taking place in coastal zones, so they need more and more water. On the other hand, the ability to supply good quality water is reducing, because we have to use the resources we have. In addition to this we see other changes in the climate and sea level rise, which will reduce the quality of the water we have even further. When the population is increasing, we need more water, but we’re also experiencing the problem of decreasing quality of water due to climate change.”

Find out more about Gregory De Costa’s research here.