Friday, October 08, 2021

Climate Change: Preparing for the flood

The Christchurch City Council has published new "coastal hazards" data, indicating which places are under threat from sea-level rise. And its not good news:

Parts of Christchurch and Banks Peninsula are likely to become unhabitable [sic] as the city council figures out how to adapt to sea level rise.

From Friday, residents will be able to see how their individual properties could be affected by rising sea levels using a new online tool launched by the Christchurch City Council.


About 25,000 properties in coastal and low-lying areas across the city and Banks Peninsula are at risk of flooding or erosion due to predicted sea level rise over the next 120 years, according to the assessment.

You can view the interactive map here. While it doesn't cover the central city area (which is also under threat), it makes it crystal clear that Christchurch is going to be a very different place in a hundred years, and a lot of its current coastal areas will simply be gone. Even looking at the 30-year timetable, to 2050, there are significant areas of Sumner and New Brighton facing regular inundation. And that's assuming we don't get any tipping point events (which can't be ruled out).

And Christchurch is just one example. Cities all over Aotearoa face this problem, and will need to prepare. The best way of preparing is to end coastal development, so we're not building anything new simply to be washed away. And we'll need to follow that up with other planning changes to ensure that people eventually move out of these areas and to higher ground. Unfortunately, what's likely to happen is what happened in Christchurch five years ago when the council last tried to deal with this threat: rich coastal property owners threatening legal action so as to bully the council into suppressing this information (thus preserving their inflated and artificially high property values, while giving them time to find a sucker to dump the mess on).