What If's purpose is to examine the Dunedin we know and the Dunedin often obscured.
Surges and sea level
These NZ researchers appear to be taking into account as many factors as are already known plus peering into the possibles and probables. "If X then A or B ... or something else, could be B+C, we'll take a good look at that" in an open minded way, just like real scientists! A pleasant change from the usual panic-making certainties.
https://www.newsroom.co.nz/2019/11/19/912610/storm-surges-to-get-bigger-in-south-smaller-in-north-of-nz#
New Zealand researchers have been trying to develop a more nuanced picture of the changes. For example, researchers in Wellington have been factoring in the impact of our land moving up and down with seismic shifts in various coastal regions.
Two research projects have now modelled the estimated impact of climate change on storms surges around New Zealand. Both found there’d be reasonably modest changes, providing a rare moment of reassurance amid increasingly dire climate projections......
Even in the North Island, where the models predict fewer extreme storm surges, flooding will not grow less frequent, because of the rising baseline effect. For regions in the South, where the surges may be bigger than now, the effect is a double-whammy. Christchurch and Dunedin are already among the cities projected to be hardest-hit by sea level rise, because of the high number of people living close to sea level.
Cagigal and Stephens agree that the main factor driving increased coastal flooding around New Zealand will be sea level rise. “The key take-home message is that sea level rise is going to be the main driver of the changing frequency of coastal events, and their changing impact,” says Stephens. “We have problems now, every now and again we get a big storm that combines usually with a very high tide ... at our highest high tides that’s when we’re most exposed, so that randomness and luck of things combining is really important,” he says.
“But that’s going to become less important in the future with sea level rise, because these impacts we see now, which only occur very occasionally, when we get all the right things lining up ... those thresholds will be reached increasingly frequently. The frequency is actually going to change really quickly [because] 20cm, 30cm, 40cm of sea level rise is going to make a really big difference to the frequency of places being flooded,” says Stephens.
There is another potential factor that is still being explored - whether heavier rainfall might coincide with storm surges to overwhelm stormwater drains and flood people from inland, at the same time they are being inundated by the sea. ..........
https://www.newsroom.co.nz/2019/11/19/912610/storm-surges-to-get-bigger-in-south-smaller-in-north-of-nz#
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Here we have yet again - speculation - this time on 'sea level rise'. The record of seal level rise is more or less 150mm to 200mm over 100 years. this is the case throughout the world and is in New Zealand. Here it has been so over the last 100 years or so.
ReplyDeleteI draw attention to the words from someone who does know what he is talking about. See below.
A quote from The 2018 Annual GWPF Lecture 'Global Warming for the Two Cultures'
Richard Lindzen, Professor of Atmospheric Physics at MIT in the United States.
'This has also been the case with sea-level rise. Sea level has been increasing by about 8 inches per century for hundreds of years, and we have clearly been able to deal with it. In order to promote fear, however, those models that predict much larger increases are invoked. As a practical matter, it has long been known that at most coastal locations, changes in sea level, as measured by tide gauges, are primarily due to changes in land level associated with both tectonics and land use.'