By James Renwick*
The final months of New Zealand’s summer carried a massive sting, bringing “unprecedented” rainfalls several times over, from widespread flooding in Auckland at the end of January to ex-tropical Cyclone Gabrielle dumping record rains and causing devastating floods across the east coast of the North Island.
After all that, New Zealand experienced spells of thunderstorms, bringing repeat floods to parts of Auckland and then Gisborne.
Cyclone Gabrielle: The science behind its power https://t.co/qDzHEmoHkb
— RNZ News (@rnz_news) February 13, 2023
The obvious question is what role climate change plays in these record-breaking rainfalls.
Some answers come from the international World Weather Attribution team, which today released a rapid assessment which shows very heavy rain, like that associated with Cyclone Gabrielle, has become about four times more common in the region and extreme downpours now drop 30% more rain.
The team analysed weather data from several stations, which show the observed increase in heavy rain. It then used computer models to compare the climate as it is today, after about 1.2℃ of global warming since the late 1800s, with the climate of the past.
The small size of the analysed region meant the team could not quantify the extent to which human-caused warming is responsible for the observed increase in heavy rain in this part of New Zealand, but concluded it was the likely cause.
More energy in the atmosphere and ocean
Many factors add to the strength of a storm and the intensity of rainfall, especially for short bursts. A crucial factor is always the amount of energy available.
Climate change is increasing that amount of energy in two main ways. First, everything is getting warmer. Rising sea surface temperatures provide extra fuel for the development of tropical cyclones because they grow by heating from below.
Warmer seas mean potentially faster development of tropical cyclones, and stronger, more vigorous storms overall. Sea temperatures must be at least 26.5℃ to support the build-up of a tropical cyclone. So, as the oceans warm, these storms can reach farther from the equator.
Second, warmer air can hold more water vapour. Every degree of warming increases the maximum amount of water vapour by around 7%. That extra water vapour tends to fall out as extra rain, but it also provides extra energy to a storm.
Driving waves further inland
The energy it takes to evaporate the water from the ocean surface and turn it into vapour is released again when the vapour condenses back into liquid water. A moister airmass heats the atmosphere more when clouds and rain form, making the air more buoyant and able to rise up more. This creates deeper, more vigorous clouds with stronger updrafts, and again more rain.
Stronger updrafts in a storm mean more air will have to be drawn into the storm near the Earth’s surface, ensuring more “convergence” of air and moisture (water vapour). That’s why, even though a degree of warming translates to 7% more water vapour in the air, we can get 20% increases, or larger, in extreme rainfalls.
All of this extra energy can contribute to making the storm stronger overall, with stronger winds and lower air pressures in its centre. This seems to have happened with Cyclone Gabrielle. Record low pressures were recorded at a few North Island locations as the storm passed.
The low pressures act like a vacuum cleaner, sucking the sea surface up above normal sea level. The strong winds can then drive waves much further inland. Add in a bit of sea-level rise, and coastal inundation can get a lot worse a lot quicker.
As the climate continues to change, storm intensity is likely to increase on average, as sea levels continue to rise. Those effects together are bound to lead to more dramatic coastal erosion and inundation.
Thunderstorms riding warming seas
These processes work for thunderstorms as well. A thunder cloud often starts as a buoyant mass of air over a warm surface. As the air rises (or convects), it cools and forces water vapour to condense back to liquid water, releasing heat and increasing the buoyancy and speed of the rising air.
Again, that allows more moist air to be drawn into the cloud, and that convergence of moist air can increase rainfall amounts well above the 7% per degree of warming, for short bursts of very intense convection. The more intense the convection, the stronger the convergence of moisture and the heavier the resulting rainfall.
Tropical cyclones have rings of thunderstorms around their eye during the time when they are truly tropical storms. As they transition out of the tropics into our neighbourhood, they change their structure but retain a lot of the moisture and buoyancy of the air. An ex-tropical cyclone like Gabrielle, moving over very warm water, can pack a devastating punch.
Why has New Zealand had so much of this very heavy rain during the weeks from late January? Partly it’s the very warm ocean waters around Aotearoa (up to marine heatwave conditions) and farther north into the Coral Sea. That itself is partly related to the ongoing La Niña event in the tropical Pacific, which tends to pile up warm water (and tropical cyclones) in the west.
But it is also related to ongoing global warming. As sea temperatures increase, it becomes easier to reach heatwave conditions. Warmer seas load the atmosphere with water vapour.
NIWA ocean researcher Erik Behrens says that Cyclone Gabrielle experienced seas heated by climate change – and “very likely” became wetter & wilder as a result. More here 👇https://t.co/HvkyzSBPf8
— NIWA (@niwa_nz) February 13, 2023
Partly, too, the air over the North Island has been unusually “unstable” lately, very warm near ground level but cooler than normal higher up. That makes the buoyance in thunderstorms work even better and more strongly, encouraging very heavy rainfall.
These conditions seem to have eased now, but severe thunderstorms continue to develop. As we move from summer into autumn, as the warmest seas move eastwards away from us and as La Niña fades in the tropics, the chances of a repeat event are diminishing. For now at least.
But if we continue to warm the climate with more greenhouse gas emissions, we will continue to load the dice towards more very heavy rain over Aotearoa. Let us hope those regions and communities so badly affected by recent events have a chance to dry out, rebuild and recover before the next extreme weather.
*James Renwick, Professor, Physical Geography (climate science), Te Herenga Waka — Victoria University of Wellington. This article is republished from The Conversation under a Creative Commons license. Read the original article.
97 Comments
Great article - and timely.
Thanks, Interest.co - it's what was needed.
It's the flipside of how our winters evolve that going to be an interesting watch for the next few months.
We've had a few years now of much, much warmer than usual winters and a handful of extreme cold weather events. Snow in Auckland being the most memorable - although the return period on that kind of event is ticking again. I wonder where it will stop.
Hard to say how much of it is age & perception vs. how much of it is actual data, but the blocking highs and marine heatwaves have been with us for a few years now, and I'm keen to see what the formerly colder months will bring.
I have a couple of old gum trees that I am about to chop up.... just in case it gets real cold.
Of course burning them may just make the next summer hotter and the following winter colder...
I T Guy,
How are we supposed to read your post? Is it just your sense of humour, or a coded message about your scepticism on anthropogenic related climate change?
If you don't believe, just say so, with your evidence of course.
He's a right winger, he can't help himself (or at least one imagines that to be the case given his endless Labour bashing). Since the response to climate change has to be government led (wow big government/regulation - TERRIBLE!) and potentially involves some sacrifice/challenge to his current way of life climate change must be a hoax/should be disbelieved.
The right wing mind is pre-programmed to be set in climate change denial mode - it really is that simple. Climate change presents a fundamental challenge to their world view, the science matters not a jot to them.
The "science" has been...selective
Dead link. Dead argument too.
Thanks, I did check it before I posted however it's not working now.
Paywalled at The Platform Climate of Fear Report by Ian Wishart | The Platform however there appears to be an available pdf here: climate-of-fear-report-by-ian-wishart.pdf (theplatform.kiwi)
Actually the science has used storms where appropriate sets of data were available. Sure, some get missed when things like the weather station is destroyed and readings can't be taken and they therefore don't have all the data points required. But the author of this piece makes so many assumptions and emotive, irrational statements, it can't be taken seriously. They appear to barely have an understanding of weather, let alone climate and often conflate the two.
For instance, he equates air pressure to rainfall, thinking that because the air pressure was low, then their must of been heaps of rain, therefore the storm must have been more destructive than current ones. Which of course, isn't the case at all. Warmer air carries more water, as the article above states. And the air and sea are definitely warmer in the past few decades. We don't even know which direction some of the storms he talks about came from, so can't predict the likely temperature of the air, more missing data.
He presents exposition as evidence, when it's nothing of the sort. When presented with conflicting readings, he assumes the worst, instead of realising that it means you can't rely on the data. He cherry picks periods to study and then applies that across all data, which is frankly, idiotic. He believes that there was no climate change in his study period (1860-1890), when in fact we started human induced CO2 rise way before that, in the 1700s.
Look at where he says "OCTOBER 1868 STORM, 959 hPa, SOUTHLAND (NOT IN NIWA)". The first paragraph makes many emotive assumptions. Air pressure must equal destructiveness (not necessarily) being the worst. The next paragraph makes assumptions about the person reading it (had they been in the job for 1 year when it was the lowest they had ever seen?) - pure speculation. It then goes on to list how Nelson was damaged and presents it as if it is equivalent or worse than recent storms... which of course is impossible to tell. The best thing he says is that NIWA shouldn't use deaths to measure severity - finally something we can work with.
Then the next one: "JUNE 1868 STORM, 980 hPa, SOUTHLAND (IN NIWA)" - cool, there was a storm, with no data. And you want NIWA to extrapolate that into a comparitive data set where there is no/limited historic information? Please.
There's just way too much to pick apart here. Shoddy "methodology", shoddy results, shoddy assumptions. If anything, it gives NIWA the chance to try and source more data to fill in the historic record better, which is great. But beyond that, making assumptions like "NIWA is trying to scare us all" is plain idiocy. More recent times, we have better data, cos we collect it in ways we couldn't back then, have more people, more resources etc. Comparing things you can't measure with things you can would only lead to faulty assumptions. Which is why NIWA only sticks to things it can measure in the past with enough accuracy to be useful.
Here's Sean Plunket talking to Ian Wishart on The Platform Was Cyclone Gabrielle really a product of climate change?. Wishart seems to be non-partisan which is nice. Remember a while ago he published a book about National party shenanigans. He makes a jolly good point in the above report. The NIWA database deliberately ignores historical data so that severe storms seem more unusual than they actually are. what a scandal. Climate change is basically a religion now. Anyone that questions it is a heretic, or a “climate denier” to use the idiotic banal language that the MSM seems to have adopted.
Wishart went down the religion track in spades, some years ago, from memory.
And he went from being an objective journalist - to being a spin-generator.
And Plunket? Spare me - he wasn't even up to it on Morning Report - and they're weak enough....
Please read my initial analysis of his "report" above. He makes a single good point, the rest is hyperbole or bullsh#t, wildly swinging between both.
I disagree bobbles. Wisharts report seems well reasoned to me. He makes the point that barometric pressure is thought to be the best measure of a storms severity according to recent research. People can read Wishart's report for themselves. Here it is. Also here's Wishart talking to Plunket a few hours ago on The Platform.
You are using a scientific study based on hurricanes (a specific type of weather event) to justify a non scientific studies conclusions which is applied to lots of other types of weather events. Which tells me all I need to know about your reasoning. When we have a Southerly storm and the barometer drops to hurricane like levels, do we get the same level of rain? NO! Because its a completely different type of weather system. Barometric air pressure <> storm severity for every type of storm, how can you not understand that?
A journalist has started asking questions, which are valid. But he has then jumped waaaay outside of his field of expertise and that is clear as his report is severely flawed. If you can't see why, then I suggest you compare the tone/structure of the scientific study you linked and Wisharts report.
Much like that video which is far from neutral/balanced where he makes outrageous assumptions. Such as "The weather in the 1800s was 20 times worse, we had a Bola level event every year". He is using the one measure to scale up to represent every storm - completely wrong headed. He is also claiming he knows exactly how bad the weather was in the 1800s based on often conflicting sources and people verbose claims in news papers. That's not data.
He is right to question NIWAs public relations stuff and their databases and their sources, but they may have valid explanations as to why prior data wasn't recorded. If there are sources that Wishart knows about that NIWA doesn't, he should definitely point them out and ask for clarification.
So you're saying categorically that extremely low barometric pressure does not correlate to storm severity in the southern hemisphere at our latitude? Where is your evidence to make that claim?
Not at all, its just one indicator. You have to define what "storm severity" means. If it means amount of rainfall, which he is equating it to, then that's absolute bulldust, if you understand even the basics of meterology and physics. Warmer air holds more water, so a tropical cyclone will produce a lot more rainfall than a cold storm. This is a well established fact. So equating tropical cyclones to southerly storms and saying their effects on human environment is the same based simply on air pressure is absolute folly, as is relying on various peoples localised observations and using that as a way to compare other peoples observations. Empirical data is required, of a quality and quantity that makes analysis possible.
That's not to say NIWA doesn't have it, its possible they screwed up a bunch of stuff, which they should definitely be called out for. But the author has gone beyond that and conducted a study full of totally wrong assumptions because they don't really understand the subject matter, which is clear from their conclusions.
I’d be surprised if the paper’s conclusions regarding MSLP (minimum sea level pressure) vs Vmax (max wind speed) as severity indicators were any different between our Southern hemisphere storms and northern hemisphere hurricanes because the reasoning is the same. MSLP represents the mathematical integral of the wind speed vector field. Big pressure difference = big wind. The fact that we have water laden dense air potantially carrying more momentum might make our southern hemisphere storms even more destructive (per given unit of pressure difference) than their northern counterparts because air density is one of the metrics in the integrated kinetic energy formula in the paper. Wishart provided data and paper references. You haven’t provided anything other than speculation.
Wishhart provided a Northern Hemisphere specific study looking at Hurricanes, which you are correct, are likely just like Southern Hemisphere Cyclones. But his paper describes much more than hurricanes, it is mostly describing Southern Hemisphere southerly storms and equating them to cyclones. You have now speculated "The fact that we have water laden dense air potantially carrying more momentum might make our southern hemisphere storms even more destructive", not me, and provided no evidence to back this "fact" up.
I am calling out the reports clear inconsistencies, the burden of proof is on the accuser. An unbiased reader can read such a report and easily spot the inconsistencies. Taking the report as truth when it makes invalid comparisons means you aren't unbiased, nor using sound reasoning. It's especially bad that you cannot see the inconsistencies even when they are pointed out to you.
You will notice I have highlighted the parts of his report where he is absolutely right, specifically around questioning NIWAs data and he should keep hammering at them until he gets an explanation. You have not admitted any part of the report is bad, so can only assume you take it as gospel. He has also gone further than highlighting bad data though and drawn specific conclusions from inaccurate comparisons in a subject area he is no expert in. It would carry more weight if he had consulted an independent meteorologist or climate scientist. His report is particularly terrible because he lacks verified data - an investigative reporters first rule when investigating each piece of data is to verify each one with corroborating evidence, which is fairly absent.
I mean he does dumb shit like this: "A passenger steamship en route from Melbourne to Bluff encountered an equinoxial storm at the entrance to Dusky Sound, Fiordland. The ship’s barometer plunged to just 28 inches (948 hPa) and the storm nearly sank the ship.". Cool, so a localised, probably southerly storm at sea with a single low barometric reading on a ship nearby Dusky sound should be treated like a cyclone and NIWA should take this boats single reading as a data point to base its science on? Anyone who travels on ships will tell you that a localised pressure drops in storm systems are not unusual, and the speed at which it drops is the best indicator for whats coming. The absolute point it reaches can be unique to them but a few km away near land, can be significantly different.
Classic. Niwa didn't check their own database. Gabrielle was a pup.
"I'm calling you out Luke. Looking back at your post Gabrielle tweets it's now clear you knew NOTHING of the historical records in that area. You clearly had no clue that 1m of rain fell in 1938. You fired up a fundamentally flawed rush study and now you and @niwa_nz are caught"
No believe. Dinosaur's 165 million years on earth. Climate change no bother them, asteroids perhaps but no climate change and they farted big time.
Growing up in Christchurch in the 80s and 90s, in winter we generally had frosts every week, often 3-4 days in a row where frosts were hard enough to freeze puddles of water, occasionally with layers of ice up to 5mm thick or so (that was not common).
Now in Christchurch, it's not unusual to have a week during winter in which there are no frosts at all, and the hard frosts with crunchy white grass are much less common.
Same in Timaru. Back in the seventies the standard overnight air temperature on a clear night through June was -3degC, with a -7degC frost. Rarely go below zero now. In fact sometimes have to wait till July before the first negative temperature.
I feel like hail in Auckland tells a similar story. We were completely whited out some time in the 1990s in Auckland one day. Then it was just hail now and then during December summer thunderstorms. But some time ago (five years or so) the like-clockwork pre-Xmas thunderstorms stopped rolling in in the afternoon, we had a big dry and now they're happening in late Jan/Feb.
Same in Nelson. My father tells me the winters are so different now even since I was a kid in the 80s. Going back further to when he was a kid its almost a completely different climate. And summers are now so ridiculously dry and hot.
But the idiots will tell you that its just coincidence that this is happening at the same time we are putting more carbon in the atmosphere and chopping down all our natural carbon sinks. Its natural processes, duh! Just ignore all the evidence which ranges from basic science (isotopic carbon analysis, green house effect etc etc) to more complex analysis with hind cast computer modelling (which is actually pretty accurate, but not perfect, cos that's impossible).
A good description of what caused the event, what about solutions? Aotearoa cannot stop or reverse climate change on its own. All we can do is prepare for the next event and respond better.
We should behave like a sensible society, know our limits, and be pragmatic about what we can achieve. Fear-mongering about climate change and some knee-jerk reaction will only hurt our economic output and standard of living without changing anything of significance in terms of the next weather event.
We cannot and should not aim to punch above our weight. We should improve our consenting rules, fortify our building code, and let insurance companies weed out risky properties from our housing stock over time. I suspect some of this filtering will be socialised by politicians, a bigger economy will certainly absorb such marginal costs but not a weaker economy curtailed by stupid climate policies enacted by a desire to be seen as a leader in climate change.
An economy is merely the processing of parts of the planet, using energy.
The energy we have used, is doing the forcing.
Yes, we can - and will have to - run on renewable energy. But we'll be doing no more than 15% of what we do now. That is why 'productivity' has stalled; why debt-blown asset-'values'; why banking is in terminal trouble. And all that is starting to unwind.
Economic output? Spare me. You didn't waste time doing economics at some stage, perchance? I'd ask for my money back - while it's still worth something, vis-a-vis those processed parts of the planet.
As a general rule, it pays to take vested-interest out of strategic appraisal - hard, I know, but worth the effort...
Renewable energy is impossible without massive amounts of fossil fuels, perhaps more than oil, gas and coal. Drill baby drill.
Agree with your comment except to quibble about 'not punching above our weight'. We need to punch just a modicum above our weight because others measure things differently and come to different conclusions. We should aim to be just ahead of the pack and especially countries that we are likely to be compared to eg Australia. For example most reports on NZ greenhouse emissions exclude international flights; other countries do the same but if you live in those other countries you can see that as NZ dodging a significant cause of global warning.
Every developed country needs to urgently reduce greenhouse gas emissions if we are to have any chance of adequately coping with climate change.
If we don't then the costs of climate change will massively outweigh your 'alleged' "weaker economy curtailed by stupid climate policies".
So take your climate change denial and stick it you know where.
Every country like china, India, and the biggest polluters that so Nothing..
Dreamer!
.why should NZ pay for others
Climate change and have little to do with emissions. Us deniers love fossil fuels and will use them to keep our quality of life. I hope you stop using fossil fuels (for my sake), decreasing demand, thus decreasing price, building a stronger economy for us that like to use them. Down here in Southland, we got milder winters, less rainfall (much needed) and an unreal summer. And the veges love it, me too.
"Climate change" by definition is a change. While weather can fluctuate from year to year, climate change is presumed to set in for a far longer period (hundreds or thousands of years).
If it did play a role in this year's weather, it will likely play a similar role from here on.
The information I want from the scientists is:
What is the change in probability and intensity of storms _per year_ updated every year.
This science is researching the change since 1880. Which is of limited value.
Many seem to believe that climate change has suddenly arrived with a vengeance. If that is the case then the per year change should start to show it.
Personally I think it CC a slow, insidious creeping change, and as such find the hysteria odd.
No mention of the Tongan volcano elephant in the room James?
"How a Tongan volcanic eruption almost guarantees a 'flooded summer' for Australia’s east coast
October 22, 2022
This La Niña event is forecast to end early next year, but don’t be fooled into thinking drier weather is coming anytime soon."
https://www.skynews.com.au/australia-news/how-a-tongan-volcanic-eruptio…
"According to a study from November by the New Zealand government research institute National Institute of Water and Atmospheric Research (NIWA ), the water vapor equivalent to 2,6 million swimming pools of Olympic standard was thrown into the atmosphere.
On October 24, the science magazine EOS, which belongs to Advancing Earth and Space Science (AGU), cited a research report by Schoeberl et al. (10.1029/2022GL100248). There, too, it appears that the amount of water vapor was the largest ever measured during a volcanic eruption. They write that up to 150 teragrams, or 150 000 000 000 kilograms, were shot up into the Earth’s stratosphere during the eruption."
https://freewestmedia.com/2023/01/05/volcanic-eruption-in-tonga-will-co…
Do you believe that the water vapour, which has gone very high into the atmosphere, is what is actually coming down again in these storms? I've not seen any credible suggestion of that.
Water vapour is a very potent greenhouse gas however - it seems plausible to me that the volcano could be directly responsible for 0.1-0.2C of warming over a 2-3 year period. Similar to how the 1991 eruption of Mount Pinatubo put enough ash into the high atmosphere to cause a detectable level of cooling in this part of the world for 2-3 years.
Increases in atmospheric water vapor also amplify the global water cycle. They contribute to making wet regions wetter and dry regions drier. The more water vapor that air contains, the more energy it holds. This energy fuels intense storms, particularly over land. This results in more extreme weather events.
https://climate.nasa.gov/ask-nasa-climate/3143/steamy-relationships-how…
https://climate.nasa.gov/news/3204/tonga-eruption-blasted-unprecedented…
Thanks for providing evidence that is in line with my comment. From the second article:
He led a new study examining the amount of water vapor that the Tonga volcano injected into the stratosphere, the layer of the atmosphere between about 8 and 33 miles (12 and 53 kilometers) above Earth’s surface.
...
The excess water vapor injected by the Tonga volcano, on the other hand, could remain in the stratosphere for several years.
This extra water vapor could influence atmospheric chemistry, boosting certain chemical reactions that could temporarily worsen depletion of the ozone layer. It could also influence surface temperatures. Massive volcanic eruptions like Krakatoa and Mount Pinatubo typically cool Earth’s surface by ejecting gases, dust, and ash that reflect sunlight back into space. In contrast, the Tonga volcano didn’t inject large amounts of aerosols into the stratosphere, and the huge amounts of water vapor from the eruption may have a small, temporary warming effect, since water vapor traps heat.
Profiles video link above, or mine to the same video on another comment further down explains better how the eruption has effected the weather to give rise to a flooded summer.
Those seem like big numbers, but how do they compare to the total volume/mass of water vapour in the atmosphere...?
USGS reckons about 13,000km3
https://www.usgs.gov/special-topics/water-science-school/science/how-much-water-there-earth#overview
Or are you arguing that a small perturbation in the atmosphere can have an outsized effect?!
If my maths is correct that's 1.3x10^16 kg of water vapour in atmosphere.
So eruption added 0.0011% = (1.5x10^11/1.3x10^16)x100
Interestingly nasa reckon it was "only" 58,000 olympic swimming pools not 2.6million...
The 2.6 million figures refers to the seafloor displacement https://niwa.co.nz/news/tonga-eruption-confirmed-as-largest-ever-recorded
If my maths is correct that's 1.3x10^16 kg of water vapour in atmosphere.
So eruption added 0.0011% = (1.5x10^11/1.3x10^16)x100
So a benign event you and NASA reckon.
I didn't say that it was benign.
https://www.smithsonianmag.com/smart-news/tongas-volcanic-eruption-blas…
The plume released 146 teragrams of water vapor into the stratosphere, which is equivalent to about 10 percent of the total water already in that layer of the atmosphere.
Sounds like a enough to impact the climate, yes.
Quite unique event in the modern record.
"The eruption sent as much as 4 million metric tons of water vapor into space, according to Larry Paxton, a scientist at Johns Hopkins University’s Applied Physics Laboratory in Laurel, Md.
“This is really a unique event,” Paxton said. “In the 20 years we’ve been making observations, we’ve seen nothing like this.
...Just before the volcano’s eruption (and purely by coincidence), a modest-sized solar storm had sent a burst of charged particles toward Earth. But the volcano had an even more powerful effect on the ionosphere, according to Claire Gasque, a doctoral candidate in space physics at the University of California at Berkeley.
Among the shocking effects: A current known as the equatorial electrojet, which normally runs west to east in the ionosphere, reversed direction, she said.”
https://www.washingtonpost.com/science/2022/12/12/tonga-volcano-water-s…
For sure it would impact the climate, but profile would like us to believe that all record breaking weather events since are down to that and nothing to do with a warming climate which they don't believe in.
.
I think the flooding in 1938 deserves to be mentioned when discussing this topic. We have have the "Kōpuawhara flash flood" near Mahia and also the "April 1938 Gisborne and Hawke's Bay Flooding". The latter looks to have had comparable damage to Gabrielle. These events are outside the considered time range of the report.
Also what are people thoughts on having a Maori English glossary on the front page of the report? I can't help but think there might have been some politics and ideology involved in writing the report.
As there is an obviously desperate need to deny, in your straw-man shoot-the-messenger posts.
Profile is paid to obfuscate - your reason?
The event is 4 times more likely in the 2023 climate. However, this estimate is not statistically significant with an uncertainty range of [0.4, 3300]. Further, the rainfall is found to be 31% more intense in the current climate, but once again, this estimate is not statistically significant (uncertainty range: -17% to 130%)
They appear to have statistical problems with their conclusions (which was apparently not important enough to mention). Maybe if they could have gone back further they might have achieved a definitive result.
Do find comfort that I find this analysis far more convincing that LtG.
Your LTG effort was a-se-backwards.
Purposely.
What is it? Your income stream? Mana? Fear?
It's not very far down....
Why is it the moment any discussion gets into computational or scientific matters, you go into this aggressive quasi religious mode attacking people on moral grounds for not having enough "faith"?
That isn't what happens with you.
You assumed the LTG crowd dreamed up a curve, then applied numbers to fit it.
I said bollocks, it was the other way around. They amassed data, then let the programme run. And they ran it with many variations - including 'two planets' (worth of resources). Prsumably they did that to fit some pre-determined curve too? Bollocks.
And that is how it is with you. I gave you stuff to read - you know, to learn from. You ran a mile, didn't you?
Then this reverse-blame stuff. Fear? You too old to change?
I don't think you understand what your trying to preach or sell (so any links or texts you provide are assumed to be equally deluded, stop thinking I accept you as a "profit of truth" or whatever). This is off topic, don't drag some discussion of legit but possibly biased attempt at modelling climate effects down to the level of LtG.
Sorry to everyone for brining LtG up.
Tim52 Check out Table 2. Model evaluation values for the statistical parameters and spatial pattern.
RCP8.5 pathway that requires a 5x per capita increase in coal consumption and no tech breakthroughs this century. Even Biden and the EPA have dropped this pathway. James really should have mentioned this to be taken seriously.
"Happily — and that’s a word we climatologists rarely get to use — the world imagined in RCP8.5 is one that, in our view, becomes
increasingly implausible with every passing year 5. Emission pathways to get to RCP8.5 generally require an unprecedented five fold
increase in coal use by the end of the century, an amount larger than some estimates of recoverable coal reserves 6. It is thought that
global coal use peaked in 2013, and although increases are still possible, many energy forecasts expect it to flatline over the next few decades 7. Furthermore, the falling cost of clean energy sources is a trend that is unlikely to reverse, even in the absence of new climate policies7
...The media then often amplifies this message, sometimes without communicating the nuances. This results in further confusion regarding probable emissions outcomes, because many climate researchers are not familiar with the details of these scenarios in the energy-modelling literature."
https://spiral.imperial.ac.uk/handle/10044/1/102624
https://www.nature.com/articles/d41586-020-00177-3
This may assist your understanding of the current level of climate change debate: you choose.
General Characteristics of Modern Cults
While definitions of a cult can vary, these groups generally have a few common characteristics.
They rush you into joining and discourage or disallow questions.
Followers are encouraged to worship a specific group leader.
Leaders dictate in great detail all aspects of followers’ lives.
Followers are personally monitored to ensure they’re following guidelines.
Methods of control are used to keep members close.
General Characteristics of Religions
Although each religion has different beliefs, there are some characteristics that group them as religions.
The group worships a higher source of power rather than a single person.
There is a shared, sincere belief system.
The main belief or beliefs are consistent with basic mainstream standards for human dignity.
Appropriate forms of conduct between people are defined.
An understanding of evil is established, especially how it impacts humans.
There are sacred ritual acts.
What??? This meant for PDK? I guess, maybe all the "alt right" content produces also figured out that NZ has had bad weather in the pass to, maybe? Or, is the cult of p>0.05(i know its arbitrary)? If not, this is next level narrative indoctrination. Where's this cult leader I'm getting this from or do I have disciples?
Clarifying your reference to PDKs "quasi religious mode", IMO climate change debate has all the characteristics of our previous holy wars.
I don't think its a cult (they could be internet neo-hippies). It's an internet enabled Dunning-Kruger phenomenon. It's a bunch of people who group though together a nice but simplistic explanation of "peak oil" and the people who came after. It was simple enough that people with a basic education could understand and let them justify a curtain morality (but not in a cultish way). Most importantly though it looks like bullshit at first glance to anyone who would correct them and they stay clear so they never interact. PDK (who is not a good representative member of the group) just has his own temperament or way of coping with dealing with people outside this group. It helps that there is an effective "peak oil" motte to retreat too whenever they are challenged (Motte-and-bailey fallacy).
I suggest Tim does some homework
Download and read Donella Meadow's Thinking in Systems
But he won't.
Dead scared of anything which might upset his applecart. .
When I when to uni, one of the things the arts students replied when their academic ability was questioned at time was "but we learn critical thinking skill [and you don't so we will be more capable than you]". What I understood this to mean was the Uni was going try teach them skill that came to others undertaking different studies naturally. I might like to think I have become less elitist over the years but when I read a book title "Thinking in Systems" from someone's who's work (with "Hindsight" knowledge) I disagree with, it gives off the same vibe. When you are providing a book or course to teach people how to "think" its either a poor use of the word or has all kinds of elitist issues among other things.
You still don't understand my criticism of the World3 model (you have yet to demonstrate any understanding of the internals of a computational model). Once you actually understand it and can convince me that you have then maybe I can show you and LtG more respect.
YOU HID!
Too obvious.
Couldn't bring yourself to read it - Whereas my shelf includes Atlas Shrugged, and most of Wishart, Richardson, Prebble, Douglas.....
Some of us are brave enough to read everything we can get, pragmatically, THEN form opinions.
You ain't one of them, obviously.
Or the 1924 floods that took out the Rissington Bridge last time.
"At one locality, 5 in (12.7 cm) of rain was reported to have fallen in one hour. This exceeds the official all-time New Zealand record of 109 mm in one hour which was recorded at Leigh, North Auckland on 30th May 2001.
Rissington recorded 512 mm (51.2 cm) of rain in 10 hours to 5pm on the 11th. Rissington recorded 229 mm (22.9 cm) of rain in 2.75 hours to 11:45am on the 11th.
The bridge was 27 ft 10 in above the summer water level showing the tremendous volume of water that must have been in the river. The loss of the bridge meant that all the country on the other side was cut off by the main road including Patoka and Puketitiri.
There was extensive damage to roads and bridges. There were many large wash outs and several bridges around the district were washed away and others damaged, including Napier-Te Pohue road approaches to Munn's bridge was washed away, Lucky Hill bridge was washed away, Fernhill bridge approaches were washed away and along Napier-Petone road the Tutaekuri bridge was badly damaged. Along the Okawa-Mangawhare road the Tois bridge was washed away.
Esk River rose 4-5 ft (1.22-1.52 m) higher than previous records, and in one place soared 6 ft (1.83 m) on 15 minutes.
The level of some Hawke's Bay rivers exceeded those of the 1897 flood. Ngaruroro and Tutaekuri rivers rose 3 ft (0.91 m) higher than the 1897 flood.
Approximately 5000 sheep and several dairy herds were drowned in Pakowhai and it was expected settlers in other areas suffered severely."
https://hwe.niwa.co.nz/event/March_1924_Hawkes_Bay_Flooding/xml
Is climate change to blame or bad infrastructure and bad land use to blame
Considering there was more rain in 1938, in Esk valley, I would say climate change is an easy excuse to justify man's stupidity .
-Lessons not learnt
-Mans dumb use of hill land
-Poor infrastructure
-The Greens stopping councils from clearing rivers bottoms, which have risen over the years
- removal of riverbank trees for dumb natives....
Climate change is a cop out!!!
A mixed outpouring there...
Yes, CC is talked about in the 3rd person - when it is actually US - and here in NZ, we are worse than most per head. Those who hide behind 'we are few' are pathetically immature, in my opinion.
Yes, dumb use of hill land, but also of flood-plain land.
Poor infrastructure? Really, not enough safety-factor; trace that back to the me-now-instantly-gratifed neoliberal corner-cutting.
What happens to river-bottoms - whether your claim is right or not - is irrelevant at these flow-rates and depths. A total red-herring.
Doesn't matter - CC is real, and we are forcing it, and we have to adapt because we equivocated too long without mitigating. Hoist with our own petard...
When a river has a volume of X and as it silts up to 1/2 X where does the water go!... Up and over the top.
Try filling you bath 1/2 with rocks and putting a full bath volume of water in it .
Comprehend now?....
The countries 1/2 full of idiots and most are blinded by their own Labour induced stupidity ...
When a river has a volume of X and as it silts up to 1/2 X where does the water go!... Up and over the top.
When a river bed has a theoretical volume of X and the amount of rain coming down across a whole catchment area that is then funnelled into that river bed (because that's how rivers work) is 10X that theoretical volume, it doesn't matter if the actual capacity of the river is only 1/2X due to siltation because 10X is still way more water than the river could have accommodated even if it had been dredged.
The countries 1/2 full of idiots
I agree. The problem is in telling who out of every 2 people is the idiot. Although sometimes it is very obvious.
Lessons not learnt or a lesson forgotten. There is a reason it is called a 'flood plain'.
Just a point or two if I may.
There is no debate that climate changes.
But there is no mention in this article to what degree man-made climate change has contributed to this weather.
And why is it that anyone that has used Climate change as the reason, has never mentioned the role of the Tongan volcanic eruption in this?
Here for example is a video https://www.youtube.com/watch?v=PDQ-EfqTViM from Australia back in Nov. predicting what it will do for a flooded Aussie summer on their east coast, and why. There are similar explanations from the States and as far-field as Europe on how the eruption will effect their weather.
But not NZ.
And here is NZ's reaction. https://www.stuff.co.nz/national/weather-news/131248166/new-study-will-…
And lastly, notice that almost everyone that is on TV speaking about the weather in NZ is from the UK or the States. Yes, they are good but don't we have any knowledgeable presentable presenters from NZ?
There severity and frequency is increasing - that's what happens with more heat.
Sigh.
We will die off through lack of sapience - deservedly...
"Declining tropical cyclone frequency under global warming
...The declining trends found are consistent with the twentieth century weakening of the Hadley and Walker circulations, which make conditions for TC formation less favourable."
Less frequent but more severe cyclones is not necessarily a good thing, and from a NZ perspective, cyclones that come farther south due to warming of southern oceans is undesirable.
Accumulated Cyclone Energy is also decreasing. What isn't decreasing is people living near the beach or on floodplains.
"This study investigates global tropical cyclone (TC) activity trends from 1990 to 2021, a period marked by largely consistent observational platforms. Several global TC metrics have decreased during this period, with significant decreases in hurricane numbers and Accumulated Cyclone Energy (ACE)."
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021GL095774
Hats off to you profile. Those two papers are highly relevant, recent, and reputable - I mean "Nature" for goodness sake. You just blew these climate change panic artists out of the water. You're always posting good stuff.
I thought modelling was a dirty word among you denier people? Guess it depends how much BS spin can be generated by torturing science, huh? How about those models showing dangerous global heating?
"Here, using a reconstructed long-term proxy of annual TC numbers together with high-resolution climate model experiments"
Not one and I repeat one, climate change MODEL has predicted the outcome of 'climate change', yet every prediction is based on a MODEL. Models are Climate change dishonesty.
And that is exactly what the metrologist in the Aussie video explains. IE the colder Antarctica (due to the eruption effects) is allowing more warm air from the tropics to drop lower and as they run into the colder latitudes etc. then they intensify and drop more rain.
But I suppose you will want to wait to hear from the two-year NZ study.
Just saying Climate change without any nuance or context, is chicken little stuff, and does not offer any solutions, except for those that benefit a small proportion of the world's population.
Colder antarctica? Sea ice has just been lowest ever...?
(Ah watched video now, you mean the stratosphere over antarctica, not the ground temps)
More fact free climate change denial - boring.
Well done for proving my point. You managed to say 'climate change', but not 'Tongan volcanic eruption.'
And what part of me saying 'There is no doubt that climate changes,' is a denial for climate change?
The part that acknowledges your guilt in causing as much climate forcing as any individual has, just by emitting at the NZ per-head average.
I apologised to our two offspring, 15 years ago. Said I was part of an enterprise which was stuffing their chances, and the chances of theirs in turn. Told them I'd do what I could do, to make matters better. And have done so ever since.
Compare that to you.....
An average without a range is a meaningless stat. in terms of the curve of who uses resources. But unless you are back at the stone age, pre-fire, then everyone is a problem to a certain extent.
You are not doing as much as you could (more than most certainly), but you are only doing what you want to, there is always more you could do, if you wanted to.
Remembering, if you are going to make comparisons, your lifestyle makes you still a heathen amongst the truly faithful.
I apologized to my 2 offspring for not consuming more fossil fuels to make their life more comfortable. But they took it upon themselves and have made it up tenfold. I just do not see the sense in my daughter, driving my grandkid to school in a Hummer.
And what part of me saying 'There is no doubt that climate changes,' is a denial for climate change?
I'm in your camp brother. It can be very frustrating discussing this stuff around water coolers from our position. You're painted with a brush quite quickly.
""a rapid assessment which shows very heavy rain, like that associated with Cyclone Gabrielle, has become about four times more common in the region and extreme downpours now drop 30% more rain.""
That seems reasonable - somewhere between total climate denial and extinction this afternoon. It matches my experience of living in cool North West Scotland where it virtually never stops raining but mainly as drizzle and light rain and then in the tropics where we would have up to 9 months of drought and then in a couple of hours the sky opened like a trillion hosepipes.
I'll take it as Cyclone Gabrielle being a 3 to 1 odds climate change event. Either way we deserved to be better prepared. So put the cause of death and destruction down to 100% greedy, ignorant investors failing to build in the right places and inadequate drainage.
Muppet!
let me get this straight.... we analysed it by …. putting it into a model to see what the model thought the past would have been like, and it's worse today. NOT, what was it like in the past from the actual data....
Replace modeling with furken common Sense!
If you bath is half full of silt and the over flow is reduce in size. .. .
..... The same volume of rain (from before the silt and overflow change) is going to flood your bathroom!!!!!!!!!!!!
FFS you young guys ( under45) need to go back to school.. . Nah!.. even the schooling these days is just woke dumb!
Well we're seeing such tremendously good results from leaving old blokes in charge of everything, aren't we?
We did until the young twats focused billions on woke, Maori ,lgbtxyz, bullcrap
Which 'Young Twats' again? Are these the kids raised by the people who apparently know everything? You know, the ones who like to scream "WHERE ARE THE PARENTS" when kids get caught doing something wrong today?
Maybe they weren't as good at that as they think they were?
Looks like your timely article has led to a great deal of debate about whether climate change has contributed to recent flooding events or not. If this debate is reflective of the feelings in the community at large in NZ we are in serious trouble if we intend to cut our emissions by roughly 50% in the next 7 years to keep the warming not greater than 1.5 degrees C. Extrapolating this to the political class in our country we have no chance of ‘doing our bit’ towards global emission cuts. Perhaps more articles aimed at the ‘observable’ destruction wrought by weather events in NZ and what we should do to respond might stimulate more useful debate as to the pros and cons of mitigation measures. Having an article from an academic based on modelling seems to be quite triggering. Personally I find it useful though so thanks.
There seems to be something missing from this discussion.
Sure la Nina has bought us the expected lots of moisture from the tropics and it has felt humid.
Sure the sea is warm with sea snakes and other abnormal events.
But something else seems to be going on. In the east of the north island it has not felt as warm as I would expect. Our garden has not performed well. We have trees that started going into autumn leaf fall almost a month ago. At the beginning of February we had some days when the day dawned gloriously fine and calm, but the morning air felt chill like the beginning of autumn. Our solar panels do not seem to be producing as much power under clear sky mid day conditions. It feels as if over the top of the expected La Nina wet warm humid weather from the Pacific, a cooling blanket has been superimposed.
I note the that the atmosphere has a hazy appearance and the sunsets look are more colored as if there is a lot of particle in the atmosphere. Is it possible that particulates from the Tongan volcanic eruption are blanketing out some of solar radiation?
You have to go with numbers, rather than gut. And even then, ask why?
We (East coast Otago) often get averagely-cooler summers if the province is averagely hotter. It's not hard to see why; the Central thermal activity is stronger, the sea-breeze is therefore stronger and starts earlier; it turns to orographic fog more often and for longer..... result; less sunshine (but 20-30k inland, 35-40 degrees and a blue sky until the sea-breeze gets there (somewhere between 2pm and 7pm, depending on the day and the distance in). A sea-breeze will often have haze, it's the pre-fog condition.
All these things. Aussie bushfires are a background factor too - particularly if that haze is red-tinged.
Yes. I remember those cold foggy summer sea breezes. Purakanui Days of cold foggy weather. 25 km away on the Taieri, blazing hot sun. But this is different. Trees don't go into premature Autumn mode without real causes. Also forgot to mention a perishing cold winter frost that killed one maple tree and nearly another. (A maple tree for goodness sake, they survive in Canada) Similar frosting but not as bad stress on 2 Rhododendrons. (I've seen them surviving happily in Stockholm.
Certainly last year there were many highly colourful sunrise/sunset events and yes, you could see a milky appearance high in the sky when the sun was nearer the horizon. Unlike Pinatubo, the Tongan volcano didn't emit huge amounts of aerosols into the stratosphere, but it did force huge amounts of water vapour there. Did the water vapour block a percentage of some wave lengths of solar radiation? I haven't seen any actual study of the effects of the eruption concerning solar radiation blocking. Perhaps there are some still underway?
Yes, I agree solar panels seem to be underperforming during bright conditions and the garden has been sluggish in South Canterbury. In saying that, Sun hours have been a tiny fraction of average through spring/summer, but it feels something extra is at play also?
"the study finds that the blast projected just 0.42m tonnes of cooling sulphur dioxide aerosols into the stratosphere – a layer of the atmosphere begins around 10km above the surface of the Earth, and extends upwards for around 40km. Meanwhile, it expelled a total of 146m tonnes of water"
https://www.carbonbrief.org/tonga-volcano-eruption-raises-imminent-risk…
Many comments have suggested more heat equals more energy equals more powerful storms. But it is energy differentials that matter. If the entire atmosphere was a single temperature, then it would result in placid weather even if that temperature was very high or very low. Is that why the worst storms are near icecaps and ice sheets which produce temperature differences in the atmosphere?
I'm still not convinced that climate change causing global warming is guaranteed to produce dramatic weather events. It might or it might not. Besides the real danger of climate change might not be storms but a small reduction in rainfall in already arid areas.
If there's global warming, how come I never used my aircon once in February, the hottest month of the year? In fact I wore a jersey...twice.
Not very scientific, but nothing's changed where I live.
NIWA warning this will be the coldest winter in 3 years.
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