A couple of years ago the Parliamentary Commissioner for the Environment warned us of a "slow-moving red zone" due to sea-level rise. According to their estimates, tens of thousands of homes and billions of dollars of infrastructure were at risk. The PCE's warning was based on sea-level rise of up to a metre by 2100 (with storm surges above that line). But there's bad news: we may now be looking at twice that:
Previous predictions for rising sea levels might be incorrect, according to a new study.
The study - published in Proceedings of the National Academy of Sciences - found sea levels may rise by 2 metres by 2100.
These findings contradict the original prediction by the Intergovernmental Panel on Climate Change's Fifth Assessment Report in 2013, which suggested there will be a rise of just under a metre by the year 2100.
"For 2100, the ice sheet contribution is very likely in the range of 7-178cm but once you add in the glaciers and ice caps outside the ice sheets and thermal expansion of the seas, you tip well over two metres," lead author Professor Jonathan Bamber told the BBC.
Globally, this means whole countries disappear, and more than 180 million people displaced. In New Zealand? Well, we just don't know, because the PCE's maps, designed to highlight problem areas, only go to 1.5m. But even from them, we can get an idea of the scale of the problem: whole communities will be going under. Central Lower Hutt will be on the beach. The cost of this will be enormous. Local Government New Zealand estimates a cost of between $8 and $14 billion for pipes and roads alone, and that's not even considering people's homes or the disruption and stress.
Avoiding those costs is a question of planning. But MfE's Coastal Hazards and Climate Change guidance for local government suggests councils use a worst-case scenario of 1.05 metres by 2100. Clearly we need some better estimates, otherwise a lot of people are going to end up carrying the can for poor council decision-making, while greedy developers laugh all the way to the bank.
