The economic effect of rising sea levels

Economic impacts can include loss of productivity of land, infrastructure and property.

Loss of property and land

Harbour and coastal erosion may adversely affect peoples’ incomes due to a loss of rural productive land. Erosion on or nearby a property can result in a reduction in the value or price of the property. Affected property owners could also find that it is difficult to get insurance or a mortgage for housing if it has or is likely to be affected by erosion.

The loss of property will arise if coastal protection works are not undertaken, or are not successful.

People may not be able to afford to repair or even demolish damaged property. Related to this are the potential costs associated with relocating a house or in the case of loss of a dwelling the costs associated with buying or renting another home.

Commercial

Depending on how the council addresses coastal and harbour erosion it has the potential to affect commercial fisheries and the aquaculture industry by damaging coastal wetlands and changing the water quality of estuarine areas. Communities dependent on coastal or harbour tourism could experience a decrease in tourist expenditure.

The reduced productivity of businesses that rely on infrastructure which is affected by erosion (such as the transportation network), or which incur costs in mitigating erosion, will have a knock-on effect on the local economy.

Community infrastructure

Coastal and harbour erosion may compromise the performance of surface and stormwater drainage systems in low-lying coastal settlements. Erosion could also damage transport infrastructure (roads and rail) by flooding and/or eroding roads. Changes in sedimentation around the coastline could affect navigation routes. Coastal and harbour walkways/cycleways can also be at risk.

This infrastructure has been paid for by residents through rates and tax. Therefore, the reallocation of public funds to flood hazard protection, infrastructure repair and upgrade, and disaster relief is a cost to the community.

Erosion protection works

Council is responsible for nearly 100 existing legally consented coastal protection structures. These range from sand tubes to timber walls to rock revetments. They are of various ages, in various states of repair and have a range of replacement lifespans up to 75 years. In total they have a current replacement value in excess of $12.5 million.

The assessment of their condition and likely effective longevity has not to date factored in sea level rise. With all hard defences any rise in sea level will have to be countered by raising the structures heights if they are to remain effective. This will be an expensive activity and ultimately may prove unaffordable and unachievable.