7 ms·
Six Sigma Deviation for Antarctic Sea Ice
- junon 3y agoSo we're fucked at this point, and nobody is saying anything about it. Don't Look Up was right. We're dumb idiots of a species.
- rf15 3y agoThe fun thing is, we cannot recognise this kind of danger. Our regular animalistic detection mechanism cannot be triggered by this, so we're kind of aware but nothing in us tells us to get away from the problem. Even as you write this, you probably don't truly believe that this could very well be the end. For once the slowly boiled frog thing is actually true.
- junon 3y agoI certainly have had my panicky days about this, so something inside me is getting at least part of the picture. Unfortunately the people who can actually do anything about this lack the parts of their brain that could ever hope to understand.
- hotpotamus 3y agoIt seems a bit like dying of a radiation overdose - a lethal exposure can take just moments, and you will go on as though nothing happened for a time, but the damage is done and irreversible.
- 11235813213455 3y agolike cigarettes, another dumb behavior of humans
- 11235813213455 3y agoover 20 years I completely recognized a warming, and I'm doing my best (no car, minimal consumption/spending, CO2eq footprint about 5% of average person in Western Europe), not many people are doing this, but there are plently benefits, not just environmental
- noneoftheaboveu 3y agoIt’s noneoftheabove that stands above the don’t look up.
- kuhewa 3y agoIt's clearly a signal of ongoing warming, but the assumption of a Gaussian probability distribution of annual ice extent- something we only have a few tens of years of data to estimate - seems peculiar.
- harperlee 3y agoI’m not a statistician, but I’ve read somewhere the argument that the gaussian is the distribution that assumes the least about its data (just that there’s a mean and non-infinite variance) so it is typically safe to use when you know little about the real distribution. (I’m just commenting to compel someone to correct me and expand on this subthread really :) )
- cozzyd 3y agoIn this case, as each day is highly correlated to the previous one, it is safe to say that the distribution of daily sea ice variation is probably not Gaussian? (Though obviously, this is very bad...)
- evandijk70 3y agoThe comparison is between ice extent measurements at the same date, at differing years, so the day-to-day correlation is not the relevant metric here, but the year-to-year correlation, which should be very low.
- cozzyd 3y agoThere's still something funny about quoting tail probabilities converted to once in X years, though, isn't there? Maybe I'm thinking about this wrong...
- kuhewa 3y agoGood tactic! > so it is typically safe to use when you know little about the real distribution. That was what the quants doing risk assessment at the big banks thought pre-2008, which is the other context I associate with the n-sigma notation for probability
- defrost 3y agoThe quote from one researcher here: Antarctic sea ice levels dive in 'five-sigma event' (abc.net.au) https://www.abc.net.au/news/2023-07-24/antarctic-sea-ice-levels-nosedive-five-sigma-event/102635204 https://www.abc.net.au/news/2023-07-24/antarctic-sea-ice-lev... 34 points by adrian_mrd 1 day ago https://news.ycombinator.com/item?id=36839757 https://news.ycombinator.com/item?id=36839757 has it a bit over five sigma and easily less than six. Still hella significant.
- 11235813213455 3y agoWhere are those persons saying that with global warming Antarctica would actually get cooler?
- roflyear 3y agoIt is incredibly easy to bash something, very hard to come up with your own ideas. To show this, reader, try to do a small experiment yourself - something your interested in - but make it really, really small. Can be testing products you use often to see which is the best for you. It is REALLY hard! And it's extremely easy for people to pick it apart. "Oh, you know more than the guys who wrote the standards?" "I've been using that for years, you're just using it wrong" "Here's a picture of me doing xyz it works fine" They spent two seconds, you almost certainly spent days and days on your really small test. This is why you won't see people back up these claims. They didn't spend time or effort getting there, and they won't spend that time or effort backing them up.
- RyanAdamas 3y ago[flagged]
- roflyear 3y agoIs this sarcasm? Almost impossible to tell. I think it isn't.
- defrost 3y agoIn order to melt ice of 0°C to water of 0°C, a high amount of energy is needed, equivalent to 334 Joules for each gram, this is latent heat. The specific heat of water is 4.190 J/(g°C). It means that it takes 4.190 Joules to heat 1 g of water by 1°C. The same energy that melts 0°C ice to 0°C water will raise 0°C water to 79.7°C which is more than three quarters of the way to boiling. We're facing higher and higher amounts of trapped energy as a result of increasing thermal insulation from CO2 ( and more and more from methane and water vapor ). While we have large amounts of ice as a buffer that energy has a sink that won't drastically* raise near surface tempretures. As the ice caps dwindle more and more energy goes towards greater and greater rates of tempreture increase.
- RyanAdamas 3y ago[flagged]
- rcarr 3y agoUsername checks out
- mschaef 3y ago> It boggles my mind that a warm blooded creature that needs arable land would be upset about icecaps melting. The earth is a large system with lots of inertia. When some aspect of it changes relatively quickly, it's natural to be uneasy. Particularly when the downstream consequences of that change are already becoming visible. To wit CO2 levels over the last 1my. https://www.epa.gov/climate-indicators/climate-change-indicators-atmospheric-concentrations-greenhouse-gases https://www.epa.gov/climate-indicators/climate-change-indica... The notion of increased CO2 leading to higher atmospheric heat capture dates back to at least 1856: https://static1.squarespace.com/static/5a2614102278e77e59a04f26/t/5aa1c3cf419202b500c3b388/1520550865302/foote_circumstances-affecting-heat-suns-rays_1856.pdf https://static1.squarespace.com/static/5a2614102278e77e59a04... So the combination of well-established science connecting CO2 to atmospheric heat, a relatively massive increase in CO2, and the emergeng changes predicted by a atmospheric heat increase - that is a valid reason for concern. > We want the poles to be livable. If it was possible to make this happen in isolation, maybe it would be a desirable goal. Given that this is not possible, it has to be viewed in context of the costs it also imposes. More severe weather is part of it, but also loss of both coastline due to sealevel rise and inland areas that become unlivably hot or newly unsuitable for agriculture. > These changes are absolutely unpredictable and the models these researchers use are so heavily interlinked and layered one small mistake in the foundational data can skew the entire output. Almost as if thats how you lie with statistics... Here you make the other sort of error - the error where you throw up complexity as a smokescreen to distract from the potential need to take action. If you're waiting for a complete set of totally accurate predictive models before you're willing to take action, you'll be waiting for a long time. > Even so, I want Greenland to be habitable within the next 100 years. Even at the expense of coast line. Have you consulted the people that live on the coastline? It doesn't take a whole lot of sea level rise before you're displacing hundreds of millions of people. (Not to mention the other associated costs of higher atmospheric energy.)
- balnaphone 3y agoPractically speaking, unverifiable and unfalsifiable. They say once in 7.5 million years, so why don’t they show the previous 7.5 million years? If that's not possible, and we only have 1989-2023 data, then the 7.5 million year comment is particularly ridiculous, as is making any generalization with data for only 0.0001% of the time span in question.
- BobbyJo 3y agoThe timespan is just a more easily digested framing of the odds. It's meant to be easier for a layman to understand, and doesn't actually have anything to do with what things would look like over 7.5 million years. That would take models with an impossible level of detail about planet scale dynamics.
- dredmorbius 3y agoI want to make clear up front that I take global warming absolutely seriously, that it is undoubtedly human-caused, and that it is progressing faster than consensus models have predicted. But the interpretations given to 34 years of highly-correlated time-series data are highly questionable and largely unwarranted. Put briefly, we have very little long-term global remote-sensing data largely because remote sensing didn't exist until the 1960s, and largely came of age long after then. As with this data series which begins in 1989. We *ABSOLUTELY DO* have many other long-term data series showing tremendous changes and associated climatic conditions: ice-core data going back 800,000 years, sea-level measurements going back a billion+ years (at which point plate tectonics are a major confounding factor), plant growth distributions and patterns dating back millions of years, and global temperature inferences also dating back on the order of a billion years or more. And yes, assuming a normal distribution, a six-sigma event is extraordinarily rare. But to make accurate inferences of such extreme-outlier events based on 34 measurements is statistical malpractice. Call this "unprecedented in the data record". Call it "extremely concerning". Find other data series with which this pattern can be correlated and from which stronger inferences might be drawn. (Note that ice-field extant data before the age of satellite observation are very thin, though outlier events such as bergs being sited in temperate waters might well occur, and that shipping logs do tend to record numerous events of interest and date back about 500 years over a fairly wide area. Indigenous records from, say, Tierra del Fuego might also note sitings over a longer period.) Sources: three years of stats courses at uni, work in stats and data reporting professionally and at an amateur level, though not an actual statistician.
- HocusLocus 3y agoWell bite me for not chiming in with some rehash of the Earths-heating-be-very-afraid greenhouse dogma, but specifically ( https://www.nature.com/articles/s41598-022-05449-8 https://www.nature.com/articles/s41598-022-05449-8 ) Persistent extreme ultraviolet irradiance in Antarctica despite the ozone recovery onset ? That is an Earth change I could sink my teeth into because our measurements of ozone are first rate, the crisis continues and Antarctica is a known target of the phenomenon.