One of our favourite Kiwi climate scientists has again made alarmist climate predictions.
The predictions come from the IPCC, but I’m sure Professor James Renwick takes responsibility for repeating them (I mean, he must have satisfied himself over their accuracy). He frequently cites the IPCC’s predictions but keeps quiet when they’re wrong. For example, when they and their computer models forecast strong warming over the last 17 years instead of the lack of warming we observe.
Of sea level rise, he says: “we are expecting something like a metre of rise this century,” but adds, “the draft report said average global sea levels would rise by up to 0.97 m by 2100 but were likely to be 10 per cent higher in most of New Zealand, where the tidal range is about one metre.”
Prof Renwick’s expertise was earned in climatology, not coastal studies, and it could just be showing. I’m told that Renwick appears to confuse storm surge elevation probability with inundation — and thus fosters false fear of the future.
Even if he was considering an area currently below sea level, his assessment would be valid only in the unlikely event that sea level rise did actually reach the extreme level projected by the IPCC.
See, most coastal areas around New Zealand are not inundated during 1% annual exceedance probability (AEP) storm surges. That means the probability of inundation is zero — no cause for concern.
Only if sea level rises enough to actually cause inundation can we assess what the probability of inundation might be. Stands to reason.
The 0.98 metres of sea level rise by 2100 (yes, the good professor gets the number wrong, it’s not 970 mm — see page 25 of the WGI SPM) is the absolute top of the range from the IPCC. Yet Prof Renwick doesn’t tell his fellow citizens there’s another side to these “predictions”.
A low side. A mere 260 mm. They’re not at all confident which one will occur. Renwick is happy to frighten us with the high figure without even mentioning a lower one. As though there’s no question.
The top figure comes from the very highest “greenhouse gas concentration pathway” considered possible by the scare-mongers at the IPCC. There’s a set of four dreamed up for the AR5; odd that Renwick plumps for the red line that soars for the stratosphere. These are the four pathways:
“We’re talking about what is now the high-tide line becoming the low-tide line and the beach will still go inland,” Renwick said, describing the increased risk to coastal areas as “a big deal.”
The IPCC freely admits not knowing which scenario is most likely. But we should bear in mind there’s NO EVIDENCE that these amounts of CO2 in the atmosphere will cause any harmful effects. They’re guessing. There’s no knowing whether 1200 ppm of CO2 (three times what is there now) will produce 0.52 to 0.98 m of sea-level rise, or whether 380 ppm will produce “only” 0.26 to 0.55 m.
There’s no evidence for any of that. In the SPM, the IPCC expresses “medium confidence” in all four of these guesses. Take your pick.
Experience (a wonderful thing — arises from observing the real world) tells us that mitigation measures are simple and, in the event that they are required for New Zealand, likely to be cheaper than trying to control our emissions of so-called ‘greenhouse’ gases.
His comment about NZ sea level rise does not make sense.
I wonder if he understands it?