‘Nick From Home’ Livestream #44 - Milankovitch Cycles

well good morning everybody welcome to Ellensburg Washington USA the local time is 8:49 a.m. and in about 11 minutes we will begin our program discussing the Milankovitch cycles good morning Linh Mike Jamie and Heather Karl are scrolling too fast now but Belgium Alberta good morning jack good morning Melissa Jocelyn so nice to see you all this morning 11:00 worth another Brussels or another Belgium excuse me Thousand Oaks California Australia all streaming live into this small backyard in this small town in the middle of Washington State terrific to have you all with us this morning it's a sleepy morning here dead calm conditions overcast the sun's trying to break through which is a surprise because it was awfully dark and gloomy about an hour ago and I think weather is supposed to be wet all weekend so I think will almost certainly be in the front porch tomorrow morning hello sleepy morning here in Japan great sleepy mornings are kind of nice another Japan good morning got a few walkers out here no muffler boys yet but that will soon change oh thank you you're commenting on the paint yeah can you yep the guys did a good job if we were with us on what was it Thursday you got a chance to say hi quickly to Alex from Casablanca painting so I asked Liz what are we doing today we're gonna hike she's like no we're nesting Jack's coming home on Monday and staying with this for a while so we got to get the house ready we also have to pick up a bunch of paint chips oh my god right can't wait for that so such as life in Middle America Ava Colette and Connell from Portland hi kids Evelyn and Isaac good morning hello JD in England and moto mining no idea what this Milankovitch cycle is that makes two of us I've been doing some doing some learning my brain hurts actually Ryan and Jack good morning you teenagers I hope you're enjoying these UK British Columbia Prince George always wanted to go up there hello from Spain hello Stacy Patrick and Evelyn Patrick is here Gorham Maine Maine cobraman man KOA a town in Maine I have one thank you this morning a little thin wispy little package and Dan from Everett thank you dan dan sent me an original grand coulee of Washington and Dry Falls this was written by Joe McMackin and it's in pretty good shape black-and-white photos from the Grand Coulee and Dry Falls but if you've been a regular with us you know that I'm very interested in those three Spokane high school teachers in McMahon was one of them at Lewis and Clark high school and to me those three high school teachers in Spokane remain the missing part of the Bret's story I still am trying to figure out how much did those high school teachers figure out on their own how much did they tell Bret's why didn't Bret's credit them if they gave if they gave him all these field sites and ideas to flesh out but there's some hints here and there Dixie said that suggests that those go boy it's one of those mornings come on now come on baby come on gotta there's enough clues to suggest that McMackin and large and trough the high school teachers of Spokane played a significant role in at least getting bread started thinking about Missoula floods so I continued to hold out hope that some of you might have some sort of link some sort of uncovered part of that story with the Spokane teachers but thank you Dan and Everett for the gift I'm very appreciative you're tuning in live here on Saturday morning at 9 p.m. I'm gonna go do some jumping jacks in just a second so 9 a.m. we're talking about the malankov it cycles that will start in just a few minutes and then tomorrow morning you are welcome to come back 9 a.m. tomorrow morning the anniversary date is May 18th of course but we don't do live streams on Monday so we're choosing to do it tomorrow morning and I haven't even begun to think about what we're doing tomorrow I've been focusing so much on today playing with all sorts of props here trying to think of how we can do this to talk about the malankov it cycles thought I'd use an apple and send a ratchet in there but I I kind of missed kind of off-center so I have a plan we'll see if it works I watched the replay of Thursday's session with sedimentary metamorphic rocks and we had major buffering issues and it remains a mystery a few of you pointed out that as soon as I really started moving the ladder around dramatically that's kind of when our buffering began and I agree with you but I've been pretty aggressive with that latter position in previous sessions and didn't seem to be a problem so whatever we'll just cross our fingers I guess I will ask right now how are we doing this morning with the streaming with the audio with the visual we're doing okay thank you yeah i jinxed it the other day I said we're in good shape I don't even have to check anymore and then of course we had major problems on Thursday night but in the replay there were a few glitches here and there but it was I think it was functional I think you could follow along I don't think you like missed out on huge chunks of it but you know I like to be casual and free and kind of freelancing but at the same time I like things to be very strong with technology and then even just kind of the delivery of the material so I do have certain standards and so when that's kind of skittish I get a little ticked off I got two minutes I need to think quite seriously and concentrate quite carefully this morning and you'll see why in just a second so I'm leaving you for two minutes to clear my head if that's possible wake my mouth up a little bit more awake my mouth up a little bit more wake my mouth up a little bit more see if we can't make this worthwhile for you this morning thanks for joining us well good morning everybody classes in session thank you for joining us this morning we're talking about the Milankovitch cycle this morning and my name is nick centner I'm a geology instructor here at the college in Ellensburg Washington's called Central Washington University we've been out of session since mid-may as most universities around the world we've been teaching from home I've been teaching my classes online and in addition to that I've been doing these live streams from my home just for fun basically and just to kind of keep things fresh and just to add some stuff to put on my calendar basically because I get a little unnerved when there's days and days and days that there isn't something scheduled I like to stay busy and productive and so the first I don't know 40 of these live streams were pretty easy for me to do I just decided I'll just you know kind of share many of these past programs that I've put on YouTube and have shared with the public and in some cases I would actually have to rewatch what I did a few years ago and remind myself and take a few notes from my program online kind of weird and then kind of dust it off and and have some live Q&A after we talk about some of those ideas well this morning is very different this morning is material I have never taught this morning is content that I never really had clear in my head until about 24 hours ago and I had a good session yesterday morning Friday morning at the kitchen table using the many links that many of you all sent to me so thank you for your generosity in addition to some a couple science papers and a couple of astronomy people who helped me just guide me just a little bit and so you're like well ok I'm new to this guy I'm watching this program I've googled Milankovitch cycles and I got to this guy in the tan shirt what's up is this some sort of expert and answers no so maybe the charm of this is you're watching a guy who's learning it as you're learning it and I have some skill as a presenter and some ways to kind of organize and connect some dots that maybe weren't there before but I am no expert on this topic this is the third of our climate history lectures livestreams in other words and a while back we did ice age climate and that's something I've taught forever involving deep sea sediments and will refer to that just a little bit so that felt pretty natural I didn't need to prep it all for that and then the next day I think it was a Sunday I had a session on volcanoes and climate and that it was new to me and I wanted to explore a few of those ideas and I was already for a bunch of you know angry comments and this is all baloney and that sort of thing and there's a little bit of that but not a whole lot this is a decent community we have but I presented that as kind of a workshop scene well this is kind of that I'm hoping to learn from you especially after you hear what I have for you with the Milankovitch cycles hey I'm interested in what you see is incorrect suppose there would be a few mistakes as I try to deliver what I learned 24 hours ago but B I'm looking to expand my knowledge of this story my last preamble before we get started is that of course this whole business of climate history has been hijacked by many different groups and as a result there's many different conflicting messages on YouTube in the media in even in science in scientific papers and it's hard to know who to believe and so all I ask if you're already if you if the guns are blazing and you're ready to go this this guy I'm going to blow big thumbs down on malankov it cycles existing number one I'm sure that and number two you know even if it does exist I'm gonna just I'm just gonna blow this guy out of the water and say this is this is like nothing compared to sunspots or compared to take your pick cows farting in the field whatever you want okay so everybody seems to have their angle and I am not equipped to have that debate my goals are simple this morning let me show you the plan for this morning it's a three-act play this morning who was Milankovitch when did he live why was he working on climate history when he was living and where was he living second the obvious guts of the plan this morning and then I have a prop I have two props I have a lamp have you noticed and I have an apple a different Apple that I showed you in the in the in the in the pre-show and so I want to demonstrate my best understanding of this I've seen this in textbooks for years I never really tried to work it for my brain and I think it works for my brain now and maybe if I demonstrate it properly it will work for your brain and finally one of the biggest messages from this morning is that Milankovitch was doing his mathematical modeling involving astronomy and Earth Sun positions decades before we started drilling into ice and before we started drilling into the deep sea sediment and unfortunately it wasn't till after his death that all of his amazing mathematical work was finally confirmed with real field evidence on planet earth and the real field evidence is layers of ice in Greenland and Antarctica and layers of deep sea sediment and the ocean floors of the world so it's one of those sad stories Alfred Wegener the the brainchild of Pangaea and continental drift he died before his ideas were accepted by science and he was heralded as a hero Jay Harlen Bretz thankfully lived long enough that he saw his ideas accepted but old ma luton Milankovitch our hero of today died long before we now realized that his work was very valuable and a major part of the last 2.6 million years worth of global climate change okay let's get into it I got all sorts of stuff written out mainly because I've never given this before and I kind of want to follow my notes and I've written my notes nice and big so we can all kind of look at the notes together so to me and I think too many the story starts in the Alps in the 1840s and if you don't know the name Louis Agassiz he's a hero to many of us in geology you know the heroes are the people who can actually think outside the box who can have a rare gift of not only imagining something but then having the ability to document it to actually do the scientific research to work into their theories and by the way just another preamble have you ever said to one of your friends ah that's just a theory you know evolution that's just a theory malankov it's I guess just a theory just a theory to me when you say just a theory implies that it's just an opinion like there's no critical thought like there's no there's not a lifetime worth of penciling out with math and physics it's just a theory and what you're really saying I think when you say it's just a theory is that well they have their idea I have my idea I guess we'll just agree to disagree implying that they're equal viewpoints but we do have experts that have way more math and physics than I do and they can back up their ideas they can test their ideas and prove their ideas that's a scientific process all right so Agassiz had this idea in the Alps that I think glaciers were much larger once upon a time and that there was something called an ice sheet and that much of the Alps he was a Swiss fella so much of the Alps were under ice maybe multiple time and not just in the Alps but major portions of the European continent were under ice at multiple times so in the mid-eighteen in the mid-1800s glaciation was in the literature really for the first time and then we jump ahead to Scotland in the 1880s and we have a precursor to Milankovitch who was laying the groundwork for the Milankovitch work we could do a whole programme on James crawl and programs have been done but let's go ahead and give you the cliff notes freelancing already this morning by the way so James crawl here's his birth and death Scottish fellow had some important scientific papers in the 1870s in the 1880s and you've seen the Matt Damon movie Good Will Hunting this is truly a guy who for many years was a janitor at Glasgow University which gave him access to the University Library which allowed himself to be kind of self-taught in many of these matters of earth-sun positions and it was crawl self-taught who first came up with some ideas in the literature to may possibly have a link between ice ages and Earth orbit variability and his work was mostly ignored by the turn of the century once we get to 1900 but Milankovitch who we haven't gotten to yet credits crawl for kind of laying the groundwork with some of these ideas and let's go ahead and jump right to the start of the show then Malou Tyndall ankov itch let me give you a similar look at his life so crawl is has passed away by 1890 in Scotland but here's our buddy mullet in malankov's and lives through the Cold War essentially or much of it we're over two Serbia and this is a life's work now for Milankovitch he has a very interesting life we could spend hours and hours talking about just his life and all of his challenges but he was a mathematician first of all but also worked with astronomy and civil engineering geophysics all sorts of kind of quantitative aspects to his work but he took crawls ideas and started penciling them out essentially and this is before computers and Excel spreadsheets etc and so he's truly spending hours upon hours each week working on these calculations trying to prove that there is some long-term climate change due to Earth orbit variability very similar to what crawl was saying but ma Lewton had the mathematical ability and the time and the dedication to pencil this out and what he came up with these Milankovitch cycles are the topic right here and you'll get my version hopefully you're the best version for me from my brain of what he was able to put together but this is sad because all those books and papers in his culminating book was in 1941 at the dawn of world war ii was not accepted not given much credence and so now we're to the 1970s let me show you my geology 101 textbook from the early 1980s I've showed this to you before I still have my hardcover textbook from geology 101 in 1984 University of Wisconsin here's my little highlighted sections as I was studying for an exam and we're talking about causes of glaciation in a textbook written in the late 1970s there's no mention of Milankovitch there's thought of possibly an astronomical hypothesis but no name or no expansion on that given given equal billing atmospheric changes Oceanic controls continental drift this I'm learning this as a young student and so there's been this confirmation of malankov itches work and really crawls work before him by this amazing field evidence that was collected in the 1970s really started the 1960s we're starting to drill into Greenland and Antarctica and then the deep sea sediment stuff as well and you know as that as the data continued to pour in somebody said hey I think somebody had already kind of predicted all this stuff in other words we see things in the ice and in the deep sea sediment that confirms the cycles that Milankovitch was talking about so sad that he didn't get a chance to see or hear the fact that we're actually teaching his stuff I'm still kind of in the preamble I feel like the context for this is important and I certainly didn't have it and you know I like telling stories and so we're getting here in just a second but I feel like the context of this might be just as interesting to help us kind of see where we are today in our understanding of global climate history changes so this was the backyard during that volcanoes and Ice Age talk and I just want to remind you that we had a discussion of the most recent 2.6 million years worth of time and that is where we are today these squiggles back and forth these ice advances and retreats ice advances and retreats my number was 33 advances in 33 retreats of the ice globally in the last 2.6 million years that is our topic today our topic today is not these much older ice ages and our topic is not this incredible amount of time during the dinosaurs prints in the Mesozoic era or we didn't have ice so we made this point last time but if you go back to a much longer timeframe there's gonna be a lot of squiggly charts here this morning you knew that if it was gonna be a climate talk right there's plenty of ways to look at our geologic past but notice these are in hundreds of millions of years hundreds of millions of years not the last 2.6 so to nut to this morning we're talking about the last two point six million years worth of time I can't emphasize that enough we get into this the last 2.6 million years that's here but notice that we've had mostly warm times in our geologic past we do have some much older Ice Ages of yesteryear but we know very little about the fine tuned cycles going on back then feeling okay feeling like we have a little bit of background here's malloon himself Malou Tyndall Anka vich and his mathematical work was really kind of focusing on these two statements that I tried to write down he was focusing on solar radiation coming in at a high latitude almost near the Arctic Circle so 65 degrees north and he knows that seasonally there's a 25% variability in the solar radiation that's coming in the solar insolation that's striking the earth at that particular latitude which is a latitude that seems to have the most I think that latitude is important correct me if I'm wrong by the way I'm not going to be apologizing all through this and say I'm not sure you've already heard my message and you know the context of this presentation so I'm just going to plow right ahead so it seems we have most of our land masses in the northern hemisphere and if we can get some of that winter snow to stick around for years and years and years and not melt every summer at that latitude that's a place where we're beginning an ice age where we're ice making at this almost of the Arctic Circle that's what I'll keep referring to this as almost of the Arctic Circle but he's really trying to come up with a mathematical model to explain why you would have this variability over long periods of time to ultimately explain why ice ages begin when they do or at least why we have a major ice advance and is there irregularity to that tied to these kinds of relationships so I could show you 17 different geology 101 textbooks they all have something that about looks like this there's maybe a paragraph of text and I've never taught it I would just casually blow it off in class or maybe a student would ask so why why do we have these big swings back and forth in this in this global climate pendulum I say well it's a it's an astronomy this is me now that's it for the last 30 years oh it's an astronomy thing you know Earth Sun positions and there's cycles that over the course of thousands of years and it all kind of works out and the translation of that is I never took the time to learn it well I got it at least temporarily up here and so we're ready now to try to figure out how this this and this mathematically proven by Milankovitch decades before we found ice cores and sediment cores that confirm these cycles what did he pencil out in those long long years in the 1920s and 30s you ready am I ready I'm ready so I'm gonna tip you down here a little bit I've got a lamp it's gonna be our son now if you're a flat earther I guess you might as well click off and go on to something else if you're not believing that the Earth revolves around the Sun I suppose sit down elsewhere right now we're gonna we're going to go in with that assumption okay the earth is a spheroid it revolves around the Sun 365 days to get us around the Sun ok a little it's a little too low I need to be able to see the full part of the board here okay so we've worked with Agassiz setting the stage for glaciation crow with coming up with the idea of variability and now we're talking about this what did my Lewton put together with these cycles I'm not going to use this earth because it's squirrely I need an axis for our rotation of the earth around its axis I did try this ratchet but I screwed up I was off-center by just a bit so I'm not using that but with the one Apple we had left pressure was on it's a Washington Apple from Wenatchee Washington a pink lady from the stim Old Orchard and I took out chopstick right between the eyes okay so this is our planet planet Earth and this is our axis I'm going to call it a knitting needle okay it's easier for me to say knitting needle than chopstick okay knitting needle right through our earth and we all know don't we that our planet spins around this axis 24 hours a day 24 hours to get us all the way around some of you are watching from the southern hemisphere some are watching for the northern hemisphere I knocked out the equator for us I'm already getting kind of a yellowed Apple here in the knotch feeling okay all right so here's our Sun here's our earth axis now I think you're aware that our earth does not have an axis that's vertical we've never had an axis that's vertical we have an orbital plane and we have an earth that's going to revolve around the Sun in this orbital plane but our axis has always had a tilt to it and during our short time on the planet you and I our tilt is 23 at point 4 degrees I always have casually said 23 and 1/2 but technically it's 23.4 ok so let's do a little bit of geometry real quick ok so there's 0 degrees tilt there's 90 degrees tilt that's not us 45 degrees tilt that's not us it's 23 point four degrees so like something like that maybe ok 23 point four degrees now let me try to hold that we're not to the cycles yet I'm just now talking about why we have four seasons every year do you know this do you know why we have seasons I'll do it very quickly in case you haven't heard this before right now I am tilting 23 point four degrees towards the Sun and at summer solstice in other words next month in June we're going to have solar rays bombarding the northern hemisphere the sun's never going to set in the Arctic right and that's because our 23 point four degree tilt is right at the Sun and Cathy and everybody down in the southern hemisphere as in winter time not as much Sun ok now for this purpose can I just focus on North America please can I just focus on the northern hemisphere in Washington in particular it's just the way my brain works don't be offended if you're in the southern hemisphere right now ok so we have summer Washington when we're tilting towards the Sun if we maintain that 23 point four degree tilt but now we're in December the northern hemisphere is dark it's darting the Sun never comes up above the Arctic Circle because we're away from the Sun and Kathy and Australia is dealing with a lot more Sun so Northern Hemisphere summer fall winter spring I'm not talking about malankov it's yet I'm simply talking about our four seasons by revolving the earth takes us 365 degree days to do this doesn't it 365 days to go around the planet and go through our four seasons with our 23 point four degree tilt capisce okay let's get to it these are the three cycles that are referred to as the Milankovitch cycles they each have an awkward name Oh blick WA T precession eccentricity or eccentricity let's talk about the first one Knoblauch what he simply means tilt and I just discussed with you that during our time on the planet our tilt is twenty three point four degrees but Milankovitch was able to prove using mathematics that there's a forty one thousand year cycle to go from a maximum tilt to a minimum tilt and back to the maximum tilt to take 41,000 years to do that max - max now these are the actual degrees of tilt and you're like oh wait a minute that's hardly it's pretty much the same like I can't even show you the difference between twenty four point five and twenty two point one right it's all just kind of like this but this is one of the factors ultimately controlling why we have ice ages be patient on seeing the connection to that in just a second how are we doing by the way sometimes when I don't see a bunch of comments I think we've lost connection or the other is everybody's really concentrating and they're not typing a bunch of stuff about alcohol and food and everything else we don't okay Patrick is okay everybody is okay it's just interesting thank you okay let's proceed so I don't know how well you can read these numbers many of these are very small just four notes for myself since this is the first time I've been teaching it but let me exaggerate for you visually a maximum tilt and get in front of the board so you can see it a maximum tilt is tilting a little bit more away from zero and a minimum tilt is tilting a little bit less and getting closer to zero so it's been proven in astrophysics Milankovitch and plenty of others that we do have this variation in our tilt angle it's not always 23.4 there are times that it's 24.5 that's a little bit more than it is now and there are times when it's a little bit less than 23.4 we actually have dates so less than ten thousand years ago actually about 10,000 years ago the Year 8700 BC was the last time we were at a maximum tilt 24.5 you see I have to cheat at my crib notes here just like you I can't read here because it's backwards you can see them better than I and we're heading for the next minimum tilt which will be in the year 11800 ad like ten thousand years from now essentially so we're kind of in between our twenty three point four it's going to smack dab between the max and the min so if I do our seasonal thing right I got to do this every year I got to do this 365 days a year but somehow as I'm doing this I need to over the course of forty one thousand years 41,000 trips around the Sun I need to do this very tiny tweaking in the angle of the tilt but again it's not an idea it's not just a theory it's been proven by multiple physicists and astronomers through the ages especially in the last hundred years that's a liquidy you'll see how that affects our global I'm here in just a second I hope let's move on precession wobble so as a kid maybe you remember having a top and you're down on all fours you're on the kitchen table and mom and grandma are talking about the gossip of the day or whatever maybe it's dad in the grandpa talking about the gossip okay so you're minding your own business down there and somebody gave you an old-school top if you're too young to know what a top is I don't know how to help you but basically we in the olden days us kids we get that common spin that freaking thing as a rule you know moving fast and it's like a frozen rope that thing is just not wobbling at all right what was that skeet thing I love that one were you like it was like a like a maze do you know I'm talking about like it was made out of wood had all these little windows from room to room or doors I guess and you had this wooden thing surprise it's got a name probably he's anybody know what I'm talking about and you wrap the string around that wooden thing and you're lined it up with the edge of that I just thought about this like I'm flooded with nostalgia right now what do you do I pull the string on that thing that whirling tin you're trying to get you're trying to watch that little whirling wooden thing how many rooms is it going to get to like it's a mouse looking for cheese at the end and that maze and off to ultimately that wooden spool thing somebody's got a name for me hopefully probably battling tops is that what I'm seeing whipping top atop eventually it starts to wobble right starting to slow it spin and so starts to yeah that's what we're talking about here we don't have a spinning top we have a spinning Apple this is the earth and now you're gonna I'm going to change my orientation you're gonna look down on our you're looking down on the North Pole now okay and so I think you know what I'm about to do instead of just playing with our tilt angle we're gonna have you're looking down on the earth now you're going to have this wobble in the position that the earth is it's got its tilt but over the course of the twenty-six thousand year cycle I know it sounds crazy how did that guy do it you can document I'm gonna exaggerate it of course this wobbles I'm still spinning the earth but I'm doing this let me do it for you this way I'm kind of tracing out a code can you see it I'm holding the bottom steady but I'm the Robin is loving this I'm tracing out a cone and now I'm tracing out the cone for you you're looking down on planet Earth shut up thank you so we can keep track of that wobble by looking at which star in the heavens the North Pole is pointing to today it points to Polaris the North Star and that's in the year 2020 that's us but this is a twenty six thousand year cycle for the Earth's knitting needle to go through one complete wobble and that wobble is Polaris wobble over to a different star Vega continued the wobble back to Polaris you're looking down Polaris is over there Vega Polaris Vega Polaris 26,000 year cycle for that now again I hope you can see we're enough to bet that we're going to be modifying solar insolation at that spot in the northern hemisphere almost to the Arctic what was the number 66 degrees north I forget what the number was 65 degrees north the point is mathematically showing how we're screwing a little bit with the amount of solar insulation at that latitude where we are prone to be making ice because we're playing with the tilt and we're also playing with the wobble of the knitting needles I hope you're doing okay there's one more and the good news is the last one is the most intuitive to my brain makes the most sense to me and hopefully it will to you back down so you can see this eccentricity I don't know why I'm having trouble saying that word this morning it's like I say I say ancient wrong can't stop it eccentricity eccentricity ich city Atlas X eccentricity eccentricity so who cares elliptical path around the Sun this goes back before Milankovitch I'm sure you'll have the name of the person who figured it out was it Kepler or Copernicus or somebody figured out that not only does the earth revolve around the Sun remember now I've got a tilt thing go and I got a wobble thing going on the course of these scales but not only is the earth revolving around the Sun it's been proven that it's not a circular orbit all the time sometimes it is circular or close to circular but other times you about know what I'm about to do a frame here hang on I'm exaggerating now but I'm showing you an elliptical orbit that the earth sometimes has as opposed to a circular orbit muffler boy thank God 937 an equidistant around the Sun more or less this also is on a cycle and malankov it's figured out that a nice round number for us is every 100,000 years you'll see some differences here in just a second so there's some variability here but let's just go with a hundred thousand just to get the concept okay so the idea is we're going to go from circle to ellipse to circle just like we did up here remember from max tilt to min tilt to man Matt a max tilt or we look from Polaris to Vega to Polaris in this case let's start with this circular or a bit we're good circular but now over the next 50 thousand years we become more and more elliptical elliptical and then another 50 thousand years and we're back to circular again another cycle this is obviously the longest period for a cycle circle to ellipse to circular over the course of a hundred thousand years now that's a rough number that works well for us but apparently that varies due to stuff beyond me so we can be as short a duration or cycle is ninety five thousand years we can be as high as 125 thousand years and then there's even a bigger major variation on that orbital pattern or orbital cycle every four hundred and thirteen thousand years you know like Oh tell me more about that I'd like to learn more about that I don't know anything about that I took calculus two from a blind teaching assistant in Madison Wisconsin in 1985 and I haven't had calculus or advanced math since then best teaching assistant I ever had by the way we're all sitting in that room twenty-five of us for the for the you know the the tea a session separate from the lecture session with the huge lecture hall we're all kind of nervous calc - this is going to be really hard here comes this guy with the seeing-eye dog coming in like trying to find the the chalkboard it's like are you kidding me and this guy is working the board glide and everything was perfect occasionally he'd be writing over stuff he drew you know a few minutes ago and we you know somebody would say hey uh race first and it was just the most beautiful it gets me choked up just thinking about it I should figure out what that guy's name is what an amazing instructors so my point is I don't have the math to help you here but these are the three cycles now here's the payoff and this is what finally clicked for me yesterday morning and I hope that this is accurate and if you're if you're deep into this knowledge and you know that this is incorrect please let me know the way these three cycles work together for my mind because all we're trying to do is explain why we're going to be making ice occasionally near the Arctic Circle you've already had the background on that phrase okay so why are we prone every once in a while to start an ice advance to making ice at the at the poles maybe you've already decided and figured it out for yourself for me I'm a slow thinker what's gonna be more favorable for ice making Max or min min max men Oh younger than thirty year old person right no gadgets screaming at each other you hear them talking about what they had for breakfast this morning okay back to the program so men max men max which one is more favorable to making ice men right if we max we're tipping more towards the Sun and we're getting more solar radiation so during our times we are a minimum tilt every 41,000 years this little men to the next men to the next men that's every 40,000 year 41,000 years we're gonna be a little bit more prone to making I see like I don't know that sounds kind of weak well let's add another factor which is more prone to making ice Polaris or Vega you know I don't know and this one's not as intuitive to me but the only way I can make sense of it yeah I'm really sketching on this actually you remember this is the spinning top this is the wobbling top so somehow these are times when our top is wobbling away from the Sun that's all I can do I don't know how to do more than that because of course we're not we're not doing this every year because this is a 46 26,000 year cycle anyway that's my weakest argument but I think there are times when we're more more the are need a knitting needle is away from the Sun more regularly because of the wobble it's all I can say and then I hope this one is the most clear to you that which is more prone to ice making circle or elliptical well it's got to be elliptical right because during these times that our earth is revolving so far away from the Sun because it's in a maximum elliptical part of the cycle doesn't it make sense that would start the next ice advance and if you recall our discussions of the records we have for multiple advances and retreats of the ice in the last 2.6 million years at least in the last million years it's been a major ice advance every hundred thousand years so to my brain it's the except it's the eccentricity it's the elliptical nature that is I don't know if this is inappropriate is this a more pronounced cycle than these other two let's try to look at some squiggly diagrams and see if we can tease out before we forget what these three strings are maybe we can tease out those differences probably ten of you I'm getting hundreds of emails a day by the way and I just say that to say that you're not hearing from me many times just because I I can't keep up but at least a dozen of you I'd say sent me a link to a program by a guy named Dan Britt and I thank you for that I'd already seen the program maybe a year ago but it was good to get those links and a reminder of his talk it's a very good talk and I took a couple screenshots so here's Dan you gave a talk down in Florida I don't know much more about him than that but here he's trying to show us one of the classic squiggly diagrams look at the time frame here we have 50,000 years a hundred thousand years a hundred and fifty thousand years all right so there's like a hundred thousand years between these two things and here is a plot of global warming and the reason I'm showing you this is to kind of give a sense of how to interpret those squiggles based on our three cycles we were just talking about it and I'll let his diagram speak for itself but from his point of view and for many the Milankovitch cycles are the dominant cycle here in other words the astronomy earth Sun position cycles Milankovitch cycles are the dominant ways to explain these sudden rises in temperature and then gradual cooling and we can even see the smaller bumps teased out from the precession and the tilt cycles and if you're really with us and have been with us for every live stream you remember squiggles like this when I was talking about volcanoes and Peter L Ward was saying this is not Milankovitch at all this is this is major volcanic events effusive volcanism creating a sudden warming and then a gradual cooling in response to that or maybe even some smaller Mount st. Helens like eruptions so you know as well as I it depends on who you listen to on what the smoking gun is but I don't know with all the math how you can ignore the Milankovitch cycles I don't know how you can just say that's not a factor and really I don't know how you can say it's anything but a major factor q the hating comments while I'm on that kind of a thing a theme with Dan Britt and then I'll finish with a little bit of data from the ice cores and the deep sea sediment and then we'll come to you with live QA I'll try here's Dan again I'm looking at it backwards so I need to look at this with you I wasn't really too didn't clued into the fact muffler boy with radio that here's the last four million years of time remember we're not going back to those ice ages of Pangaea and things like that this is quote unquote quite recent but Dan and many others that I've been reading recently suggesting that here's the beginning of this ice age that we all confirm is the last 2.6 million years worth of time warm cold warm cold warm cold warm cold fine but starting about a million years ago the ice ages become more spaced out and more intense so if you can read my chicken scratch here it seems like between 2.6 and 1 million years ago there's an every 41,000 year squiggle that's a familiar number that was our tilt business but then things nobody's been able to explain this by the way even the Milankovitch people I don't know who the mangle that's a good name for a rock band now ladies and gentlemen put your hands together for the Milankovitch people but starting 1 million years ago we have these more glaciations greatly increased in intensity and the periodicity is every hundred thousand years so he's enlarging that for us and showing this regular 100 thousand year cycle so why is that why why would this Trump this starting a million years ago if that's really what we're seeing I'm on Dan Britt here so I'll finish with one of his other major slides that I thought was quite interesting and you might have to just take a screenshot of this and really look at it carefully I don't want to hold it up here for 10 minutes but he's basically saying Dan Britt now is basically saying we should be cooling right now if you if you if you now understand them the length of its cycle and you understand the periodicity of this Dan Britt and others are basically saying we have been removed from the malankov it cycles because of what we've been doing in the last few thousand years and especially the last couple of hundred years and you know what I'm talking about but this chart I promise I'll hold it here for a second if I can get the focus to work he's basically looking at some of the cycles that are Milankovitch and looking at the past and the future and his main point is we should be what we're seeing in the ice core in the deep sea records especially the ice core records are showing us that we're not following this Milankovitch cycle any longer obviously a debatable topic among even within science and if you are a hardcore science person and a greenhouse gas person co2 person and you're just waiting for me to give that cell that's not my focus today and I don't know that data very well that's kind of next I think I think I need to do another one of these I don't know if I'm gonna promise but I think I should do another one and look more carefully at the ice core records and the trapped gases in those bubbles and I saw a bunch of comments the last time I didn't want these climate things and they're like you're doing the you know you're doing everybody great disservice by minimizing greenhouse gases and carbon dioxide I but my gut feeling from dealing with so many different kinds of people especially folks who are not into this at all like don't deny all this is that once we get into greenhouse gas discussions and and other kind of human activity the lights just go out that it's just like this guy selling me something and so to me that's this threshold that I'm I'm I'm afraid to cross until I have enough field evidence that I can be convincing along the style of this I hope you can understand that okay I have five more minutes so to finish the story Milankovitch passes away a couple more decades go by malankov itches work is all just like whatever you know somebody lost a time whatever some somebody in Serbia doing some math I roll and then we start drilling into the ice and we start drilling into the deep sea sediment and here's just a quick look at some of the work done with the deep sea I'm sorry the deep sea sediment drilling in the 1970s so my textbook was not you know takes a while before the research is confirmed and then gets into textbooks so I'm not slamming my textbook author but these gentlemen were working in the 1970s with deep sea sediment records and being able to look at cycles of oscillating sea surface temperatures and the amount of glacial ice that was our ice age climate talk remember our oxygen-16 variability with the deep sea sediment and micro fossils and that you might have to go back to that live stream if you didn't see it then John's doing some time series stuff I don't even know what that means but the thing I really wanted to show you is plotting Milankovitch cycles look at the time frame now this is you always have to do that right what are we looking at the last hundred years the last thousand years the last million years you know they're all just squiggles so that's always the first thing like what part of this barcode are we looking at in this case they're going back a thousand years it's also frustrating because they got sometimes present day on the right sometimes present day on the left but this is I like this one because it's talking about the Milankovitch cycles we were just discussing today contributing to variability and solar insulation or solar forcing they're calling it at that certain almost of the Arctic Circle and then here's our understanding from the ice about glacials and interglacials and trying to link those up and you're like well I don't know I don't do they link up I'm not even sure well here's another one this is from the Vostok Antarctica ice core there's lots going on here these are overwhelming plots but I just want to give you a sense what are we looking at now present days here this is four hundred twenty thousand years so we have direct field evidence from the ice in Antarctica drilling through the core drilling through the ice sheet at Antarctica we can count years and go back four hundred and twenty frickin thousand years I didn't know it was that long that's impressive almost half a million years of direct evidence I have to do more with ice cores I'm such a fan of putting your finger on some field evidence as opposed to invisible whatever it feels like most of the conspiracy stuff and other kind of alternative facts movements are all based on stuff we we can't put our finger on I think magnetic field changes are hot in that world because you can't really easily see the magnetic fields or the co2 or have you heard and in the submarine canyons underwater there's such and such it's I I don't think it's an accident that all these kind of inaccessible or invisible pieces of evidence are then taken and kind of hijacked for another story but to me if you can get to a core put your finger on a year capture dissolve and trap gases in bubbles in the ice volcanic ash layers etc this is like looking at layers in the Grand Canyon at least we have a chance of having some common ground between these different groups so I'll go back to the plot but coming directly from ice cores that collectively go back four hundred and twenty thousand years not the most sexy looking plot but they're plotting on the same chart here carbon dioxide changes methane solar variation that's the Milankovitch business I'm reading backwards oxygen isotopes and what's that one relative temperatures so if you're unaware there is major work today and certainly has been major work for the last 50 years of taking ice core and deep sea sediment core data and trying to correlate it with these Milankovitch cycles and that's why it's being taught now that there is an agreement between the mathematical models of James Kroll and malloon Milankovitch and a bunch of this real data coming out of these places the end thank you for your attention it's time for some live Q&A I'm going to do my best to answer what you have to ask please proceed while I collect my laptop this ought to be good from marbles collector what hard data did Milankovitch use to be able to calculate these things like how on earth did he come up with this that's a great question I don't know so he started this work in the 1920s and I don't think it was a total outsider I think he was Czech I can't remember some of the famous names that he was dealing with or or kind of working with so I think he was able to get some data but what data would it be I don't think they had ice cores that early I don't know how he was able to work like again to Dan Britt Oh actually we got a look Oh hold on we gots a couple of cozy four things you want look at a couple cozy fourth things it's already 10 o'clock so I'm gonna give you a couple tips there's a three minute program on James Croll on YouTube it's called Roy Thompson on James Croll I don't want to take the time to watch these I was going to but that was really in case I kind of had a brain problem I just said let's just go to youtube this is an excellent I think the best program online to conceptualize the Milankovitch cycle and and so I was so pleased with it it solidified so much for me and then I went down to the comments and I lost the will to live and the future of our planet is doomed based on all those comments but it's the amazingly beautiful Milankovitch cycles and their profound effect on climate change and seasons the guy in Scotland who it's it's not a particularly sexy tone and it's quite dry but he's got some animations in there and he lays it out so perfectly that I strongly recommend that it's like I'm recommending books now but I'm not and then I did gain quite a bit from Dan Britt you can read it as well as I can so I drew heavily from those especially the last two that I suggested to you but it's already 10 o'clock so I don't think I want to show them to you back to your questions that I can try to saw great question marbles collector I don't know we can record we can record that and I can just hit replay bill any connection between the migration of the magnetic pole and precession well bill I know you're a geologist so quite often the the angle is talking about the magnetic field etc as the way to solve most of these problems and I'm always leery of that but in your case I mean if I'm serious about continuing to do these live streams and occasionally trying to do something brand-new like stuff I always meant to look into it's the magnetic pole stuff it's the magnetic field stuff and a lot of people are fascinated whether it's kind of conspiracy angled or just regular and of course in geology 101 we really only talk about the magnetic field especially the normal versus reverse polarity magnetic field story with evidence for seafloor spreading on the oceans of the world but I don't know of any connection bill between the migration of magnetic poles and processional you're asking just about the wobble many of these might just be questions I'll read and just go yeah good thought all plots are sexy says Murray does precession cause ice ages well Melissa as I understand it it's a combination of all of these working together and that never really felt right to me in other words I couldn't teach that just kind of say well they all these cycles kind of converge or eventually you get three parameters kind of intensifying in effect I did my best to kind of talk about what I thought was appropriate or kind of the the high ice maker signal for each of those parts of each cycle let me find that plot again so I have no idea how extreme this is or if this is common for people to take global climate record over a hundred and twenty thousand years let's say and try to show how eccentricity precession and tilts are all creating a signal here but you can see from this at least that that those cycles are not equal so this is my best way to show how precession is a factor but none of these by themselves appears to be The Smoking Gun and many of us are smoking gun type people we feel better we only feel good if we can get one like obvious answer and everything else we can just say as noise or that's common you know if you see these presentations it's a volcanic signature in the last 2.6 million years for global climate jeez everything else is noise it's a malankov its cycle story everything else is noise it's a sunspot story and everything else is noise you know what I mean by noise you know the the cycles are the the variability there is hardly anything it's not explaining these crazy changes Daniel did the Milankovitch did Milankovitch ever work with Brett's and will you do a live stream on Mount Rainier and the Cascades Daniel thank you for the question age 12 I believe so Milankovitch lived in Europe and Brett's lived in North America and I'm sure they were not flying back and forth at that time they also separated time wise as well so I know that they didn't work together but their stories are similar to Daniel I mentioned Bret's today because both of those men worked very very hard and for most of their life in the case of Malou ttan all of his life he had an audience of just a handful of people that confirmed that what he was doing was important and valuable that's always a sad story to see that I have talked about Mount Rainier in the past a little bit I think next week I haven't going to do a la Jara show not just with Mount Rainier but other volcanoes it seems like people are wanting a show like that I see a bunch more upper case here hang on what did you want to include in this talk that you didn't I bet it's interesting I kind of wanted to include some of where we are now with greenhouse gases and focusing on if the malankov it cycle is still controlling us I think another part of this is why don't we have major malankov it's cycle signals earlier than 2.6 million years ago I just don't think we do so like most things I think there's things to work on so I wanted to do more about Milankovitch versus signals that we have now but I don't know about the signals greenhouse gases etc well enough so that's motivation I might ask Susan Kaspari who I work with who does ice core work to join us one of these nights and see what she wants to add to this maybe she's watching now with her kids can effusive events be linked to the Milankovitch cycle well elaine that's an interesting thought so I like some of what Peter L Ward was doing obviously because I shared it with you the effect the global effects of you know major flood basalts and the gases that are degassing from the earth during those times and tying those to mass extinctions is there a way we can tie some effusive Vulcanus Val Kanaka vents does it have to be either/or between the volcanic story in the Milankovitch story I don't know if anybody's tried to really link those together wouldn't an ice age kill far more creatures than global warming asks bad-hair decade wouldn't an ice age kill far more creatures than global warming I'm not a biologist bad-hair I'm sorry I don't know how to answer that I'd answer it if I had the background how does the moon affect the cycles as Rick again as promised I think I'm just going to read people's questions it's not taught that the moon has much effect on global climate at all what resources do I use or trust to learn science topics like this that's a good question Maury Longo especially with this branch of geology climate variability of course it's very difficult and I don't know if you've if you've watched enough of my stuff to know that I'm not really a follower you know the way I operate the way I choose to teach and dress everything you know I just I just I like being I kind of like listening to my own voice and so I'm not naturally one who just follows the fashions that are in science and I'm here to tell you that there are our fashions in science or there's a hot topic and everybody's kind of listening and repeating what they hear and and sometimes even within the science world it feels like you get away from the field evidence or it's like some you know news story that runs its course and it's like whatever happened to pit bulls being dangerous you know their science equivalents of that to you I tried to give you the sense of that here nobody's talking about Milankovitch in 1975 and now it's a major part of the program so that's my best way to answer that question to specifically answer your question I'd known a little bit about Milankovitch from geology 101 textbooks I found some videos that I thought were fair and balanced that's I can't believe I just use that phrase fair and balanced but I tried to find resources that use the field data and that's where I'm going next if I'm serious about doing another one of these with global climate I want to go to the ice cores I think exclusively and I want to learn what I can about the ice cores themselves and I feel like I'm just looking for stuff that I can sink my teeth into that is clearly not pushed on me with a certain angle that's within science or not and it's hard to find those those kinds of resources Jamie and Heather date under precision Polaris on the chalkboard 200 but I just picked our date 2020 I don't know where we are in this cycle I guess we're at Polaris right well I know we're at Polaris can watch the cose Ford sorry these are running too long I just looked at the running time from some of these in the last two weeks I got to scale this back Gavin aged 11 where are we now in the Milankovitch cycle well Oh Gavin I'm not going to show you that plot again I'll just kind of do it verbally according to the few resources that I really tried to sink my teeth into dan Brits talk in particular his main message was we're in the malankov it's cycle where our glaciers should be starting to grow these three things I'm talking about we should be cooling right now in other words if this crazed is this very let's just say the last million years we've had this hundred thousand year cycle according to Dan Britt now I'm putting too much credence in one guy basically because I don't have a whole lot of background his and many others say that that we should be cooling right now and yet we're warming quite dramatically and so stay tuned for another program where I try to look at data that's more recent that's obviously where the the most discussion will be the device nine wonders if Milankovitch had data from glaciers he may wear hub well III don't I I don't know could the cycles contribute to volcanic eruption activity could the cycles contribute to the eruption activity Cheryl well we still don't totally understand what drives the tectonic plates a whole nother area I know very little about this is geophysics we're talking about now there's no obvious connection that way I can see why you're thinking that but I don't I don't see how that would work so the three cycles all some so the three cycles all sometimes line up like turn signals blink at a red light like turn singles blinking at a red light I think I get that something like that yeah it's a it's a good attempt at an analogy there maybe it's an excellent one and I'm just not bright enough to follow it pic availa magnetic pole reversals versus Milankovitch cycle yeah I am seeing a lot of people want more about magnetic pole reversals I can tell you that the last magnetic pole reversal was 780 thousand years ago 780 thousand years ago is the most recent flipped from a reverse polarity to a normal polarity and we've had what at least a half a dozen major ice advances in that since that time so just directly I don't see how magnetic pole reversals influence global climate but you're asking about the Milankovitch story I still think the Milankovitch cycles these are lots of time but it's still short time periods compared to at least almost 800,000 years since we've had our last reversal more questions along the same lines excellent live stream follow the money to Al Gore's house that's that's an example of hijacking the topic there's so much that's been tossed into this discussion that it's it's paralyzing for most couple more will quit any thoughts on the variability increasing as the residual heat of the planet bleeds off I assume that's been looked at somehow Mike I don't know more than that could we use explosives to set off volcanoes to cause global cooling Tanner in Everett well tanner surprisingly you're not alone in suggesting setting things off like 30 years ago when I started teaching a college class somebody raised their hand in the middle of a volcano discussion so why don't we just like you know make the volcano erupt so that we don't have to worry about it we can control it and I was like completely surprised by that I get that question every quarter every quarter oh we're worried about volcanic eruptions or even earthquakes why don't we just like you know set something off so we can have the upper hand and my answer is always do you want to be the person to set off the explosive these are forces that are so much bigger than us so thanks for the idea but it doesn't seem like a good idea to me there's so much we don't understand and many of these forces are so much larger than us that it's difficult to visualize us controlling it I'm seeing many of the same I'm sorry if I'm missing your well-thought-out question and if there's some specific contributions to this discussion with Corrections or additions I look forward very much to reading what you have to say a toast to you as a little teaser for tomorrow morning at 9:00 a.m. which is the anniversary weekend of the mount st. Helens eruption here in Washington State 40 years ago and by the way it's all over the media etc and there were all sorts of live events that were supposed to happen this weekend to commemorate but of course we're all at home a little teaser I think it was Tuesday Nunda night of this week I drove up to Snoqualmie Pass and I met a woman that's no Kwame Pass and we hung out for an hour and she loaded boxes into my van tune in tomorrow morning to see how that has to do something with the 40th anniversary of Mount st. Helens what did she load into the back of my van to you and your health to the health of your parents in your grandparents and your children and your grandchildren all of your extended family how about their health here's to their health and your health of course mental health is a special topic for us these days I hope your mental health is hanging in there the best you can you're getting good exercise and you get some fresh air and you get some sort of a break occasionally from the stresses that you've been experiencing I thank you for tuning in this morning I hope you have a pleasant day or a pleasant evening depending on where you're watching around the world and maybe we'll see you tomorrow night and by tomorrow night I mean tomorrow morning at 9 a.m. Pacific time good day from Ellensburg Washington I love you goodbye

Channel: Nick Zentner

Views: 45,437

Keywords: Nick From Home, Nick Zentner, Milankovitch Cycles, Greenland ice cores, Antarctica ice cores, deep sea sediment cores

Id: 3cA5A4dZ0gs

Length: 91min 7sec (5467 seconds)

Published: Sat May 16 2020