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Triple-dip La Niña confirmed as BoM makes declaration (scimex.org)
98 points by indigodaddy on Sept 17, 2022 | hide | past | favorite | 160 comments



> Known as a “triple-dip,” a three-year La Niña stint has only occurred three times since record keeping began: from 1954 to 1957, 1973 to 1976, and from 1998 to 2001.

So basically every 20 or so years and the last one was about 20 years ago.


It might be interesting to compare the severity of the three prior triple-dips with the current one. My zero-research guess would be that this current one is worse than the last.


I was around for the last one in Sydney. Anecdotally, this seems like the worst floods. But that could also be because we’ve had 3 major events in a row: massive forest fires, pandemic, multiple bad floods.


Interesting! The '97 & '98 ones were intense, I remember.

I think ever since then it's had higher awareness in the larger population but I have no way of knowing.

It was a significant enough event to even be represented in entertainment[1]. ;-)

[1] https://www.youtube.com/watch?v=F5tttyTWXzU


that’s not la niña though..?



Is this due to global warming?


These la nina/el nino cycles seem to be long period climate patterns which already existed, because they’re measured in decades and we don’t have records for all that long n is very small and quite hard to determine if there are anthropogenic effects to them.

Things people forget with climate is that there are indeed long cyclical patterns not all of which are well understood which have significant weather effects. You can’t just yell global warming every time there is an apparent change or bad weather.

If you are interested in truth and not just a political narrative you have to be curious, open, and ready to acknowledge not everything is going to fit the popular doom stories.


I agree with you but in a situation like this it’s a lot better to overreact than to underreact. If we do more than we need to, we get cheap solar panels, long lasting batteries, and maybe a lot of time and money wasted on ideas that didn’t work out. If we do less than we have to, we get a possibly irreversible feedback loop of global warming that leads to the collapse of most habitats (including ours) on this planet.


Overreact is practically "Boy who cried wolf"

There is such a thing a social capital that you have to spend wisely on real important things. Else, you'll lose trust and you can't play that card again


The wolf is already at work. Just go hiking in the Alps and look at the extend of the glaciers, take a look at the raining/snowing patterns over the past 50 years, everwhere you look you can see the effects.

You can call it what you want, but anyway if we want to live long term on this planet we need to reach an equilibrium with our environment. We definitely can't achieve this by pumping oil and gas out and burning it.


Glaciers have been melting in the north since the last ice age though. It may go faster now than it did 100 years ago, but with or without more CO2, glaciers were going to disappear many places.


In the very long term, and even then it was uncertain as the planet would be on a cooling trend right now. Even then, we’re talking about “glaciers might disappear in 10 000 years” versus “80% of alpine glaciers will be gone in a century”.


It's speculative so who knows. But northern Europe was covered fully by ice 12000 years ago. There has definitely been more melting since then, than what is left.


Did you pay attention to the boy who cried wolf? There was a wolf. It ate the boy. The villagers didn't do a thing to stop it.

You'd better hope this isn't a "Boy who cried wolf" situation.


Exactly my point.

Environmentalists cried wolf for "Nuclear Powered Solutions". They cried wolf for "Natural Gas Fracking". They cried wolf for "GMO".

Now, they have lost social capital and don't have credibility for "Co2 emissions"



But what if it's a smaller deal than some suggests and people in Europe now are going to freeze and potentially even starve because the transition to environmentally-friendly energy was completely botched?


It’s not though.

There are a large volume of people who question the validity of climate change at all, exaggerating only causes more doubt and recruits for the opposition.

The doom scenario of “irreversible collapse” is also quite unlikely but some people really like scary stories. And to be blunt any practical imaginable progress is not going to be a very big change, if it’s going to happen the damage is already likely done.


Hasn't there been multiple variations/iterations of "validity of climate change"? As in, some form of "climate change isn't real" to "climate change is real but it's normal and not man made" to "climate change is real and man made but it's not that bad" so on so forth.

I wonder if the opposite exists. People in climate change denier groups that exaggerate just how normal it is which as you said only causes more doubts and recruits for the opposition.

I admit I haven't delved into the "opposition" - in this case assuming that "deniers" are a loud minority and the main agreed viewpoint is some form of climate is going to be bad for everyone regardless of the source. But given the rigorous process in science and how much evidence is available (whether deniers are skeptical of ALL of the evidence or not) - is there any research with a similar process against it? Regarding what you said about how the "irreversible collapse is also quite unlikely"?


Haldane's theory on stages of acceptance:

1. This is worthless nonsense.

2. This is an interesting, but perverse, point of view.

3. This is true, but quite unimportant.

4. I always said so.


You said yourself it’s not well understood, don’t you think it’s wise to err on the side of caution? What’s the downside of getting off fossil fuels anyway, besides some people needing to switch careers from coal mining to solar panel installation, for example?


It's wise to care about the climate. It's wise to investigate human behavior's effect on climate. It's also wise to question investigations, their results, and especially their conclusions.

I don't know what a downside to getting off fossil fuels would be but its not hard to imagine some. Take this article for example : https://www.abc.net.au/news/science/2016-06-15/what-is-an-ic... I seriously doubt the scientific basis for the statement "The Earth is due for another ice age now but climate change makes it very unlikely" but it's one idea.


The downside is not having heat in the winter in Sweden. There is a pretty significant downside there.


Electric heating is a thing, and so is nuclear power.


Nuclear power is great. Unfortunately the environmental groups that lobbied for renewable energy, also lobbied against nuclear power. So much less available nuclear power for Sweden in the winter, than there should have been.


The false dichotomy is very damaging. It’s not nuclear or renewables. We need both, and as much of either as we possibly can. Neither nuclear or renewables would be enough to get rid of enough fossil fuels on their own.


But it doesn't make much sense to combine them. Wind and Solar, as well as nuclear have similar cost characteristics. The cost of an additional unit of energy produced is very low, almost all of the cost is in building them & keeping them running. It almost never makes (financial) sense to throttle them. Thus nuclear being a so-called baseload. It doesn't make much sense to use it in any other way (for example, like a peaker-plant).

Both are best served with a complement that has low(er) capital cost but higher cost per unit of energy produced like storage or gas plants (maybe with P2G) for periods of high demand or when generation falls flat (mostly for renewables, but as we're seeing in france some nuclear reactors are having trouble as well in high-temp environments).


> But it doesn't make much sense to combine them.

On the contrary, it makes a lot of sense.

They have complementary production profiles, with nuclear providing near/constant levels for time scales from days to years. This mechanically reduces the amount of energy storage needed (storage at the required scale is still very much not solved).

They have complementary risk profiles. Wind and PV rely on weather and are likely to fail us when the weather gets really bad, i.e. when we’re already in crisis mode. Nuclear failure modes are very different and combining them makes the grid much more resilient overall.

There is no realistic scenario in the short to mid term future where we can have 100% wind and solar without either a massive overproduction capacity, or overly-large storage capabilities. The rise in wind+PV is accompanied by a rise in gas and charcoal use.

Nuclear also has the advantage of taking way less land for the same energy output. Yes, this is important if we want at the same time to reduce our dependence on fossil fuels used in agriculture, which will reduce yields and thus require more land for the same amount of food produced, and keep our forests as carbon sinks (expand them, actually).

> Wind and Solar, as well as nuclear have similar cost characteristics.

Cost is only part of the story. If we follow the path of the smallest costs, we’ll just burn oil until we hit a wall.


It does make sense to combine them. Manufacturing renewable energy sources requires lots of cheap energy, and can be done in remote places, and currently uses fossil fuels. Use nuclear instead as the base of the energy pyramid (like food pyramid).


Nuclear power is not great and environmental groups were and remain correct to lobby against it.


The precautionary principle is attractive, but it ignores the possibility that lost opportunity costs can exceed those of the risk being avoided. Turning on the lhc was considered by some to have a miniscule risk of turning earth into a tiny black hole that would last a moment before evaporating. My particle physics friends laughed and agreed there was a non zero risk. The notion that an action with a tiny yet finite risk of an event with infinite cost should itself have infinite cost would preclude most everyday activities. Not that climate change or emissions fit that category I think the risks aren't that small, just saying be careful with the precautionary principle.

Some amount of climate change would probably be beneficial to some nations. Russia would vome to mind with more arable land potentially becoming available, but some models show it being borderline too dry to grow on. Those same models show a net benefit to agriculture in Midwestern US. I wonder if xkcd or 538 could whip us up a map of climate change winner/losers and areas that support co2 policies?


> What’s the downside of getting off fossil fuels anyway,

Poverty?


The sooner we transition, the sooner we’ll be able to become vastly wealthier: the GDP growth rate is highly correlated with the growth rate of energy consumption. The growth rate of energy consumption has been declining since around 1970, hence the decline in the GDP growth rate. This is because it’s ever more difficult to extract ever more energy from fossil sources. Once we transition to renewables, the GDP growth rate will rise as our ability to increase energy consumption rises, until some point of saturation far in the future.

One way to think about this is to consider that a hypothetical objector might ask the same question of an advocate of a planned, civilization wide transition from wood burning to coal burning. And the coal advocate would be right to make the same argument as above.


Getting off fossil fuels is a necessity. Don't kid yourself what the result of that really means.

"Transitioning to renewables" what does that even mean? Like it's so simple?

Solar panels aren't going to ship you cheap iPhones and mountains of plastic trash from china for pennies, nor will it fertalize your crops or maintain USD as the reserve currency.

Look I don't mean to be rude. I'm not a climate denier. I'm not even arguing against transitioning off fossil fuels. I'm just not naive about it. Poverty, starvation and mass death is the only way we transition off fossil fuels. That's if we're lucky.


Is your argument that renewables aren’t usable for liquid fuels in ocean shipping, therefore we can’t use purely renewable energy sources? Because solar panels (or wind turbines, or geothermal, or hydro, etc.) can generate electricity to use for electrolysis to generate hydrogen (or better, ammonia). The options aren’t only oil or batteries… there are many use cases where fuel energy density doesn’t matter that much, but where it does (transport), hydrogen is a viable option that we can do today.

https://www.bbc.com/future/article/20201127-how-hydrogen-fue...


Yes, it is that simple, and yes, solar panels can be used to ship iPhones from China and fertilize crops and so on. And no, poverty, starvation, and mass death are not required to transition.


There are a large volume of people who believe that demons and ghosts are real: https://www.usatoday.com/story/news/nation/2021/10/28/do-gho...

I say that just to point out that popularity doesn't provide legitimacy. But with that case I'd assume that there just might be a significant overlap between that example and climate deniers.

The doom scenarios have enough possibility and probability to warrant being taken seriously. Wishing it away on future generations is psychopathic.


If we over react we get an unstable grid which is incredibly fragile and doesn't work in the winter. Just look at Germany today. The only country to voluntarily de-electrify itself.


My understanding is that they have actually added brown-coal capacity to their grid. The problem wasn't a fear of climate change, but of another Fukushima type event. They have been ramping up wind, and they have fairly reliable wind, but wind patterns can shift too.


Exactly which pre-existing climate pattern is responsible for the hockey-stick graph, and when is it going to let go of the accelerator?


Not likely, but it does lead to cooler global temperatures which provides a temporary respite from global warming. The last couple of years would have been way hotter if we were not experiencing la niña conditions.


> Not likely, but it does lead to cooler global temperatures which provides a temporary respite from global warming.

Indeed. The Niña episodes after 1998 were a big part of the denialists’ talking points about the end of global warming for the next decade.

> The last couple of years would have been way hotter if we were not experiencing la niña conditions.

Considering how 2022 is going, this is actually frightening because it means that the next couple of years are likely to be way worse.


You mean things happening on the same frequency that they always happened?


You're assuming that this one is a three-year La Niña. You'll know whether this is a 3- or ≥4-year La Niña in about 18 months. The warmest seven years since records began have all been since 2015, so I wouldn't bet against a La Niña record now either.


But you can say that about anything.

How do you know the weather won’t be 50C tomorrow in NYC?


That would be a a very big surprise. But I could say "don't assume that today is the last day of this extremely hot weather, it might go on until tomorrow or even longer" and that would be much less remarkable. You don't know the end of an ongoing event until it's past.


I mean, a 4 or 5 year La Nina would also be a very big surprise.


4 year la Nina is a big surprise, but a 4 year la Nina given we've had 3 years already is a much smaller surprise


That’s not how probabilities work.

If I flip a coin and get heads 3 times in a row it doesn’t change the odds on the 4th flip.


It is how probabilities work. A plain example: The odds of flipping ten heads in a row are 1/1024, but if you've already flipped nine heads, the odds of flipping ten heads are 1/2.


Can you please tell me in detail how you're not agreeing with what I said? I said the exact same thing.

"If I flip a coin and get heads 3 times in a row it doesn’t change the odds on the 4th flip."


It's not the odds of the fourth flip, it's the difference between four flips and a fourth flip.

Look upstream, you'll find someone (you perhaps? I don't care who) who doesn't realise whether the current La Niña situation is equivalent to a fourth-flip or a four-flips situation. A common problem in statistics, in my experience: People sort of understand two statistical statements, but then apply the wrong one to the real-world situation they're in.


Temperature rising are more a gauge of urban sprawl then anything else


"always"

When they started measuring these things climate had already started.


s/y\ always/last\ three\ times\ it\


Might be clearer if you just write in English.


And to keep it snarky there is “ftfy”


I mean it's quite clear, but yeah a direct question would be easier for everyone to understand at a glance


s/\/\/\//\\\\\\g


Don't have to escape the slashes, non?


The back-slash escapes the space. And the training slash is missing.


Sorry that's what I meant. It's not necessary to escape the spaces.

s/Jesus Christ/Jesus, the only begotten son of God who came to Earth and died so that we may be saved from our sin,/g

Is a regex I ran as a young fellow in scriptures who had exhausted spacing as a means to hit minimum essay size.


Bad habit from vim, sorry :).


Ever since we started keeping track of it.


> Is this due to global warming?

Global warming was the old narrative... You mean "climate change".


Yes, everything that happens now is because of it.


Possibly, but in isolation it’s impossible to tell. Weather is a series of events; climate is a statistical phenomenon.

But basically yes, all bad and exceptional weather is caused by climate change, at least in terms of moral equivalence. Many people somewhere is suffering from climate change, and you should pretend that it’s you, because you want to have the mindset that it has hurt people most everywhere.


Setting aside how silly it is to think about weather in this way, you’re also just plain wrong.

Despite the doom and gloom marketing from those seeking to put their hand in your wallet, most people will definitely NOT be negatively impacted by climate change.


Most people won’t be negatively affected? How do you justify that? How many people in the USA southwest are affected by the mega drought? How many people in China are affected by their mega drought? How many people in Europe are affected by the heat waves? How many people on islands and coastal areas are affected by sea levels rising? How many peoples are affected by glaciers melting and less snowpacks (such as villages in the Himalayas)?


> How many people in the USA southwest are affected by the mega drought?

This is a bad example because the area has gone through similar mega droughts over the last 5000+ years. The Colorado river compact was setup after an unusually wet period and now that the flow has returned to normal they are paying the price.


I’ve been in car crashes before but that doesn’t mean I’m ok with increasing their frequency and severity.


Plenty of questions there. Do you have any of the answers?

Ah, right. This problem is so terrible and sneaky that we (quite conveniently) can't even measure its effect! Just to be safe, we should just assume everything bad is caused by this spectre.

Luckily, some very smart people who are not at all self-interested have told us that if we make great sacrifices and spend enough money that will help us avoid this impossible to measure problem.


How is anything the poster stated not measurable? We can measure the rise of ocean levels, the rise of global temperature, the number of people on said coasts etc...

Take off your tinfoil hat for a quick second.


It makes for great agitprop: play as cardboard characters of perfect virtue or absolute evil.


What are you and GP even talking about?


Hockey stick graphs are just astroturf agitprop in the class of endofunctors, what’s the problem?


When Newton saw that apple fall from the tree, his first thought was:

- I just found a way put my hand in bequanna’s wallet!


[flagged]


I get the strong passions in this conversation, but I don't think name-calling helps anyone.


It’s not going to convince anyone, I know. It’s just I get tired of dealing with small brain nonsense like this. Wind and solar are cheaper power, and from friends looking for tenure I know that any “doing it for funding” is imaginary. If they haven’t been convinced by now, no logical argument could ever possibly convince them. I could use an argument in pure mathematics, and they would say there is no evidence for any of my axioms. They keep asking for evidence and debate, but they are simply lying. I’m just returning the same level of respect.


You have a choice:

1) Say "you're so dumb" and everyone flags you, so you have little impact on the conversation

2) Don't say "you're so dumb", and enough people will vouch for you that your comments are visible


If strong emotions were facts, I suppose you'd win this argument.

Let's see what you think in ~10 years when the newest, focus-group tested climate crisis de jour is being pushed after "climate change" is quietly disproven and stops being sexy.


I studied meteorology in university, and I’ve read a lot of papers in climatology and adjacent fields. Please come back and talk to me once you understand atmospheric radiation, the Madden-Julian Oscillation, ENSO, the Paleocene-Eocene Thermal Maximum, how isotopes can serve as proxy data, general circulation models and how they are modified for climate, economic models of ecosystem services, and how tropical storms cause economic damage. I’ll wait.


If anything your wallet is lighter because of the push for "green" technologies, which are usually much more expensive than "dirty" ones. Just compare price of Tesla vs ICE car. Not to mention things like "carbon tax" (already partially implemented in the EU)


If like myself you are confused as to what the byte Ordered Mark has to do with weather, BoM is the Australian Bureau of Meteorology.

Triple dipping refers to this being the third year of La Niña in a row.


I thought it was Bill of Materials


HNer's religious devotion to "Don't change the submission title" is sometimes infuriating. It needs to say what BoM is and that it's confirmed in Australia.


Only takes a quick glance of the actual article to gain clarity on it though.


There is no need to make comments like that, others will just complain about it.


Which is not always a reason not to say something when you believe it's important.


Even if it is important, there will still be an overwhelming amount of people who will not care


That goes both ways. Even when something annoys you, there are a lot of people who don't care.


That is quite the confusion you got there. As la nina is a weather event, how is it related to Byte ordered Mark?


They were just defining the unknown acronym in a playful way, presumably.

You got the joke, but didn’t even notice.


I was actually thinking it meant bill of materials. I am a programmer with construction background


Lol, fwiw this was my initial reading as well.


The last 2 summers here in Sydney have been pretty much a writeoff due to the rain. And then before the double La Niña we had the bush fires of 2019 where the city had some of the worst air quality anywhere of the world. The (general shoddily built) houses just aren’t built for this weather - I’d say that more than half of my friends, family, and work colleagues have had to deal with mould in their apartments and houses.

A huge reason for living in Sydney is the quality of outdoor life, then combined with extensive lockdowns, insane housing prices, and an openly corrupt and overbearing state government, it’s not been a great place to live for a lot of the population in the last few years.


Wow, what a lot of hyperbole. Could you please show us some sources for the “openly corrupt” government?

I’d also like some more information about the shoddily built houses. If we’re talking insulation then yes they’re not particularly well insulated compared to a Nordic country. But we also have a very mild climate compared to Nordic countries.

New McMansions aren’t particularly well built but that’s the consumer driving the massive floor plan/minimum cost.

Building, like any other product is very much up to the consumer in terms of what they want to prioritise.

Specifically on mould, if the ambient humidity is, on average very high, no matter how well built your home is things will go mouldy. The solution is mechanical dehumidification/cooling but that comes with other penalties.


The previous Premier of the state (Gladys) resigned due to corruption. The new premier is involved in a plot to give sweet fake jobs to his political buddies, as well as various other schemes. The previous Labour government got swept out because of massive corruption. At a federal level, NSW politicians are involved in water grafts (Angus Taylor and barnaby Joyce) as well as huge handouts to nonexistent companies (great barrier reef foundation got 700 million dollars with no office and 5 listed employees and have done nothing visible with the money - except to say that it's been spent). NSW is very openly corrupt at all levels of government.


First page for “NSW corruption”

https://www.abc.net.au/news/2020-10-15/nsw-history-of-corrup...

https://www.smh.com.au/politics/nsw/barilaro-petinos-and-unu...

First page on “NSW building defects” - 1/4 of all new apartments have defects. That’s just apartments and excludes houses being built on flood plains and heat islands in Western Sydney

https://www.theguardian.com/australia-news/2021/oct/14/more-...

https://www.climatecouncil.org.au/urban-heat-island-effect-w...


I have migraines triggered by changes in the weather. The last two winters have been the most miserable of my life.

This most recent winter I had a migraine that lasted an unbelievable 63 days starting the day after Christmas.


While I definitely agree climate change is a clear and present danger, how do you know that your migraines are weather related?

Sounds like a conflating of correlation and causation.


Your skepticism is reasonable. It does sound like an extraordinary claim.

The relationship between migraine and weather is a studied phenomenon. I admit that I don’t personally understand the research on this topic, but I trust my neurologist.

I do know that the proxy data for weather changes is barometric pressure, so it’s often specified in that way: “changes in the barometric pressure cause migraines for some people”. However I find the concept easier to explain to people with the phrase “changes in weather” because, in my experience, most folks don’t really know the relationship between the barometer and the weather.

The Mayo has a layman’s discussion on the topic of weather and migraine:

https://www.mayoclinic.org/diseases-conditions/migraine-head...

EDIT: I forgot to mention. I “know” about the correlation because I’ve done hundreds of days of migraine journaling over the years and used that to find probable triggers. Unfortunately, that’s essentially the state-of-the-art in the field. :-/


It's funny to me that people have unlearned the relationship between pressure and weather. I grew up in a house with a faux-antique barometer, and always took that for granted. Like reading an analog clock, this isn't knowledge that "kids these days" pick up. Which is still weird, because TV weather announcers always talk about the pressure when describing their weather forecasts. But of course, people want to know if their BBQ is going to be sunny, they don't want a lesson in physics.

https://www.amnh.org/explore/ology/earth/make-your-own-weath...


I grew up in the Pacific Northwest, where there isn't much severe weather, but spent a few years in Atlanta in my 20's, where you get tornado warnings.

After about a year in Atlanta, I was able to predict a tornado siren going off about one or two minutes ahead of time nearly every time. All I know is that I'd be going about my business and, of out of nowhere, the air would feel different. I can't explain it any better than that, but it was such an obvious feeling to me and blew my mind having never been in that situation before.


Humans are much more animalistic than we want to admit. Our senses are insanely attuned to our surroundings, but modernity overwhelms them. Oh well, trade offs I guess.


Honestly though, a proper prediction with various inputs is more accurate than eyeballing a barometer, and aside from this particular type of migraine, why would anyone need to know the pressure during the normal course of one's day? (Assuming your work doesn't happen to use environmental pressure.)


> why would anyone need to know the pressure

Rising and falling pressures are a decent enough heuristic for weather behaviors in local areas.


We’ve even lost most of “looks like rain” - the average person a hundred years ago or so would have been able to relatively reliably predict the day’s weather in the morning.

Many of us can’t do that now, even if we do go outside.


> changes in the barometric pressure cause migraines for some people

I am with you. Have you considered moving to a geographical location with smaller pressure variations? Helped me a lot.


Have you looked into how much energy/noise it would take for a fan to add those couple missing millibars to your house, to make the change more gradual? Assuming mostly gradual weather changes most days, it might be able to catch many of the big changes if you are able to stay at home for 24 hours after the change.


Does it matter whether it’s correlation or causation? Maybe the weather causes something else to happen (like releasing more allergens or whatever), and that causes their (and my) migraines? Who cares? When the weather changes, many of us experience migraines. It doesn’t really matter whether it’s causation or correlation and your questioning it does nothing to help the people suffering or to educate those reading the discussion. It’s just dismissive for no reason.


Do you get a headache on an airplane when it’s ascending or descending?


I think I do, but there are so many other things in the airport and on airplanes (noises, smells, bright lights) that trigger migraine that I can’t really say for sure.


Last I read was that the meeting of ice in Antarctica is increasing the probability of extending La Nina (sorry I lost the source). There are theories about ENSO states becoming more frequent with climate change, the most favoured one was a more stable El Nino (see PNAS article by Lenton on climate tipping)


How will this affect winter temperatures in Europe, wrt limited gas supply?


Wetter and colder in the north, warmer central Europe. Alps usually get a lot of snow. https://www.metoffice.gov.uk/research/climate/seasonal-to-de...


Previous year (presumably the second consecutive La Niña event) the winter was exceptionally dry in the Alps leading to the current unprecedented snow and ice situation in that area so at least that year the snowfall was very limited.

The article states that the predictions should't be regarded as forecasts so obviously some years might not have the expected changes, but in addition the only expected effect of La Niña in Europe seems to be a drier autumn on the Iberian peninsula so I'm not sure how you arrived at your statements.


If the additional snow results in snow-covered roofs then it might actually help. 15cm of snow is very efficcient insulation.


Melbourne's gigantic Thomson Dam is nearly full - a rare event.

DamCam: https://www.melbournewater.com.au/water-data-and-education/w...

200KM from Melbourne, the Thomson is the main water storage and holds 1,068,000 megalitres. For comparison, Sydney harbour is 562,000 megalitres.

The Thomson is at 96% full, and in fact most of Melbourne's dams are full or nearly full according to:

https://www.melbournewater.com.au/water-data-and-education/w...


Many dams (Oriville for example) are important parts of flood mitigation - isn’t having the dams nearly full bad for that? Or is the rainy season over?


I don't know about this dam, but Wivenhoe in Brisbane has various grades of flood capacity.

100% is full of drinking water. This isn't actually "full" and the dam can hold this amount of water twice again - 300% capacity.

Up to 200% the dam operator can choose to close or open the dam. Above 200% the dam auto-opens and can retain water to 300%. Above 300% means the dam holds no more and all additional water runs downstream.

iirc above 280% the dam wall could be compromised and risk collapse, leading to 0% capacity in a big hurry and the worst natural disaster Queensland would have ever seen.

The dam manual for the dams near you is most likely on the govt water website (like Wivenhoe). Settle in for a long PDF which only an engineer could love.


That's what I was thinking - "100% capacity" can either mean "the design load (still usually 3-5 feet below the overflow spillway)" or it can mean "full for our purposes (power/drinking water, etc)".

The first one is the fun one.


Some dams have additional capacity for flood mitigation, like Wivenhoe Dam in Queensland. Unfortunately that’s not fool proof either: https://en.m.wikipedia.org/wiki/2010%E2%80%932011_Queensland...


If it were, i think they'd drain off enough water between storms to preserve some reserve capacity for flood control.


“Between storms” - no such thing for the last Australian summer


If you're asking about California, we're about to start the rainy season.


Melbourne doesn't have a rainy season.

But when the USA droughts we flood due to La Nina.


As somebody who lives on the side of a hill, that ended up with lake views out the bathroom window, I have one word, and it starts with F.


This is terrible. My Australian friends are complaining endless rain during summer is ruining their quality of life.


Well let's hope Autralia steps away from being a major coal producer


Not likely, it's central government has been completely captured by coal interests. You could say they have been "carbon captured" _sunglasses_


Both major parties in Australia are busy using tax money to destroy the great barrier reef (and tens of thousands of tourism jobs) so that a coal mine can open and provide a few hundred jobs.

Don't hold your breath


For people like myself who live on top of a hill, it's been pretty good not having 40 degree heat

For people in lower-lying areas, it's been less good


After cancelling holidays for covid, they are now rained out.

In addition mould is a big issue. Takes weeks or months to fix. Potentially could write off a house. “ And those are the “first world” problems before you talk about actual floods.


The 3 “once in a century” flood events haven’t been great either


Is there any link to climate change & flooding?


Not Australia, but a recent study[0] confirmed the Pakistan flooding (in which 10% of this country that's larger than Texas is underwater) links to climate change. Historically, tying events like this to climate change in a way that lives up to scientific rigor has been quite difficult, but techniques and available data have been improving. Allowing us to tie many extreme weather events to climate change, including: the seemingly never-ending droughts in the Horn of Africa, Mexico, and China, flash floods in West and Central Africa, Iran and the inland United States and searing heat waves in India, Japan, California, Britain and Europe. They refrained for making estimates for the Pakistan flooding, but earlier this year scientists found that the heat that scorched India and Pakistan this spring had been 30 times as likely to occur because of greenhouse emissions. July’s extreme heat in Britain had been at least 10 times as likely

If you're looking for a mechanism of action for how climate change can make monsoons more deadly, it's likely to do with increased evaporation of water due to increased temperatures and the fact that hotter air holds more moisture

[0] https://www.nytimes.com/2022/09/15/climate/pakistan-floods-g...


Increased instrumentation/data could also lead to bias in the data through increased volume. I’m sure there’s a name for this effect.


Measurement bias?


the bias could be in either direction


I will take a leap of faith and assume this isn't intended as a joke.

Yes, CO2 traps heat in air, trapped heat in air means hotter surface and hotter air, most of earth's surface is water, hotter surface means more water vapour, hotter air means more capacity to carry water vapour, water vapour forms clouds, clouds lead to precipitation.

Climate change is leading simultaneously to two issues: not enough water, too much water.

The former is obvious why: more water in air, means more rain, combined with more heat means more and bigger hurricanes/typhoons etc..

At the same time, due to more complex effects, droughts occur. Basically that is happening in regions where wind and ocean currents are not transferring moisture in to the region, but heat is causing evaporation. Other effects also contribute (eg. reduced snow pack in mountains, leading to there being less ice to melt to keep rivers flowing).

You can google "what is climate change?"


Yes.


Dublin would like to have a word with them.


Sydney gets almost double the rain that Dublin gets.

http://www.weather-guide.com/Weather-Comparison/Dublin-Sydne...


Sounds better than drought, so long as there is no flooding.


There’s definitely been flooding.


Queensland sometimes gets both.

The floodwater destroys everything but sweeps past without soaking in.


It can be just as bad if not worse for crops


Lismore,NSW would like a word.


Believe will cause dryness in certain parts of US (Southwest perhaps)


Is there no better way of communicating climate conditions in 2022 than an arbitrary suffix of an arbitrary noun?


Here's the site they link: http://www.bom.gov.au/climate/enso/


awesome ski season then?


It usually means below-average snowfall in Colorado. Other states might fare better than us.


100%. The real strength of knowing these oscillations is the ability to get ahead of the cycles if you know they're coming.

La Nina is great where I live, El Nino is not, but the reverse is true elsewhere.


The last one was terrible, what are you talking about


Was great in the PNW


I ought to check it out this year. Where’s your favorite place to go?

I’m thinking of how last year wasn’t hardly any snow and quite a few meltoffs in the east (where I did most of my skiing because of all the madness at the resorts all over). And the year before that worst avalanche year in memory for Colorado, if you do any backcountry


This sauce sounds delicious!




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