Global warming strikes again...

[El_Machinae]

They are. And they're disconcertingly powerful. They were able to migrate to post-truth headlines better than nearly anyone.

 

[carlosMM]

Been telling you, get into the info I linked to. Again, drink.

You didn't link info, you linked a very broad search result.

--> are you chickening out of the discussion here? Or are you going to actually try and back up some of your weird claims?

 

[CavLancer]

Nope, not chickening out at all. You must realize that with 20 people raised in the propaganda throwing out posts it gets a little wearisome. They want me to cave, tell them they are right and I'm wrong and all that, but are they willing to carry the weight of some of the paperwork involved in raising this question? Nope. They ask a complex question that took me years to arrive at the answer to, a complex answer not a lot shorter than reading all the links in the google search page I was kind enough to link (No thanks yet btw) but aren't real interested about getting their complex question answered I guess. Its kind of like asking an astronaut how he ended up in space and he just points to a college and says, "good question, start there." Its a complex question with complex answers.Also, I'm into this thread through next Spring, the answers to the questions won't come from me, but from the climate. What is climate el Sahib you say? Climate is a crap load of weather.

If I were to try to answer those questions I would have to refresh at all those links I pointed out! Been there, done that, your turn. Have you ever heard of Father Guido Sarducchi? A great philosopher of the '70s. Here is his opinion on what people retain from their education. The point is there is a ton of minutiae that goes into making an opinion that might not be at the fingertips of the person being questioned. Here's the great man himself Carlos, enjoy:

 

[Synobun]

Why would we thank you for linking to information that does not even support your claims?

 

[CavLancer]

Human kindness?

 

[Bootstoots]

But the politics associated with climate change is exactly mass hysteria, alarmist groupthink, or conspiracy. There is a major disconnect between what politicians want to happen and what is supported by the science.

J

The science supports the conclusion that humans will likely push the planet's CO2 concentration up to 500-650 ppm by the end of the century, with the lower end of this range only being accessible if we curtail our emissions quite a bit faster than we're currently doing. If we say that we manage to limit it to 560 ppm (2x preindustrial) at the end of the century and are carbon-neutral from that point on, then what we expect to happen is an eventual warming of about 3 C from preindustrial levels, with most of that increase happening throughout the coming century. That's a pretty big deal, no matter how you slice it. Sea levels will rise at 0.5-1.0 m/century for around a millennium, which is a big problem, as is the large and unpredictable shift in precipitation patterns that will lead to floods in some areas and droughts/famines in others. Although the politics around global warming can get annoying, and apocalyptic predictions can be dismissed, the real amount of concern is not disproportionate to the risks.

Well Boots, I also agree that global warming is real. The globe warmed seriously during the 90s, and again these last couple years during ElNino, which ended a period of slight cooling aka, "the pause". That El Nino is now pretty much over and I believe "the pause" will resume. Its cause will anyway, as solar cycle 24 is continuing its drastic downhill plummet. Add to that the PDO, as well as La Nina and it should be much cooler soon, which is why I chose now to start this thread. I consider that a period of global cooling is upon us. If the solar scientists are correct solar cycle 25 will flat line and cause major cooling, devastating cooling. At that point I think we'll miss the good 'ol days of global warming. Many predict that this cooling will last between 30 and 150 years, but I don't see why in might not be the end of the Holocene. Boots, have you seen any predictions about what will happen when the Holocene ends? Its inevitable of course, has anyone done a paper that you've seen and can link to?

The "pause" wasn't really anything, just a brief period of slow temperature growth that can be explained by a lack of significant El Nino events in 1999-2014 and increased heat flux to the ocean vs. the atmosphere and land. The 1997-98 El Nino and the 2015-16 El Nino were about equally strong, but the temperature anomaly in 1998 (vs the 20th century average) was 0.63 C while the one in 2015 was 0.90 C; 2016 will probably be even hotter than 2015. Temperatures will then retreat a little bit and fluctuate up and down within an increasing trend as normal, and by 2020-22 there will be new claims of a 'pause' since 2016 because that's what happens when you start a trend line on a local maximum in a noisy data set.

When the Holocene will end (or would, without human interference) depends on the Milankovitch cycles, a variety of regular cycles in Earth's axial tilt, which pole faces the sun when Earth is closest to it, and the eccentricity of the orbit. Ice sheet formation and growth is triggered by low solar insolation (amount of energy received) at high northern latitudes. When there's low insolation in northern Canada or Siberia, snow that fell in one winter will not melt entirely during the summer, and a buildup of snow develops that turns into an ice sheet. Once the ice sheet starts, a big feedback appears because they are both cold and reflect most light that hits them, cooling down adjacent areas and causing ice to form there too. They then grow over glacial periods of ~100,000 years until they reach about 40 degrees N in North America and a little north of that in Eurasia. Then, when a high point in insolation occurs, they start to melt at the more southerly latitudes. Once the melt starts, it creates a feedback that favors rapid ice sheet melting: white ice is replaced by dark ground, warming adjacent ice, and so on. This is usually much more rapid than the process that causes ice sheets to grow, and the result is that we went from the end of the Last Glacial Maximum about 20,000 years ago, with North America buried in ice down to central Illinois, to the Holocene where temperatures were as warm as today by 10,000 years ago.

The Milankovitch cycles are currently in a mild period of relatively little variation, in which the cycles are mostly canceling each other out. It doesn't look like we are in any danger of having a new glacial period be triggered until about 50-60,000 years from now. This is unusually long for an interglacial; during typical interglacials, solar insolation dips below the threshold needed to trigger ice sheet formation within about 10-15,000 years. But we're in an unusual calm period in the combined Milankovitch cycles.

Here is a graph of all of these cycles and their effect on the amount of radiation that arrives at 65 degrees North (black line, 5th from the top). You'll see that we're actually at a tiny local minimum on that measure and will see slightly increased insolation over the next couple thousand years, then drop back to about the levels of today, and then climb again and plateau for a little while before finally having a significant minimum around 60,000 from now. It does not look like we're headed into a new glacial period for a long time, although I will concede that it's probably nicer for humans to have a CO2 concentration of about 350 ppm rather than 280 ppm. Going well beyond that, though, destabilizes our climate fairly rapidly and results in change that we're not prepared for.

Spoiler Milankovitch cycles :

 

[Lexicus]

Temperatures will then retreat a little bit and fluctuate up and down within an increasing trend as normal, and by 2020-22 there will be new claims of a 'pause' since 2016 because that's what happens when you start a trend line on a local maximum in a noisy data set.

 

[CavLancer]

Correct me if I'm wrong Boots, but roughly speaking every 90,000 years there's an interglacial the average length of time being roughly 11,000 years. Iirc. So, 90,000 cold then 11,000 warm, 90,000 then 11,000, 90,000 then 11,000, 90,000 then 11,000, very roughly. Just read that we are 11,700 years into the Holocene, not 11,500 as I said earlier. So basically there is half a million years of precedent here. Now you're saying what? That's all over? Well if its over its over, but perhaps it needs more looking into due to that extraordinary precedent. Got another question for you and your friends. Did the Milankovitch cycle describe the earlier interglacials with such amazing regularity? I think the pat answer is yes, but if Milankovitch described the previous 5, I want to know how those cycles changed because then they're not cycles anymore. Part of my concern regarding the Holocene is that those cycles don't match previous warm and cold periods. The oval orbit repeating every 100,000 years would match the time frame if we did not currently have a circular orbit with only 3% variance iirc and the Holocene is due on the time scale to end, if the last half million years mean anything. Its not set to end you say, yet the pattern of 90,000/11,000 is established. So, while I think Milankovitch might have something to do with climate, I doubt he's the 800 lb gorilla of the 90,000/11,000 cycle. So, that would leave some other pattern or pulse of energy to describe it. Which the sun might be the likely culprit, with some long term pulse that we don't know about. Either that or we get another umpteen years of interglacial, the last half million years be damned, and wouldn't that be nice? The fact remains that the sun's magnetism is going into a huge valley, particularly if solar cycle 25 goes as predicted. The sunspots have tanked. So we're going at least into a minimum, and that means cold. You're describing a circumstance Boots where that is the result, assuming I'm right about CO2 not changing that result much which I think you would say that CO2 is so bad that it won't make much difference.To me a minimum would be much preferred over the end of the Holocene of course.

 

[Bootstoots]

Correct me if I'm wrong Boots, but roughly speaking every 90,000 years there's an interglacial the average length of time being roughly 11,000 years. Iirc. So, 90,000 cold then 11,000 warm, 90,000 then 11,000, 90,000 then 11,000, 90,000 then 11,000, very roughly. Just read that we are 11,700 years into the Holocene, not 11,500 as I said earlier. So basically there is half a million years of precedent here. Now you're saying what? That's all over? Well if its over its over, but perhaps it needs more looking into due to that extraordinary precedent.

It's not over, it's just that the Milankovitch cycles have lined up so that they're all roughly canceling each other out for the near future, so that there won't be any real extremes in either direction for the next 50,000 years.

Got another question for you and your friends. Did the Milankovitch cycle describe the earlier interglacials with such amazing regularity? I think the pat answer is yes, but if Milankovitch described the previous 5, I want to know how those cycles changed because then they're not cycles anymore. Part of my concern regarding the Holocene is that those cycles don't match previous warm and cold periods. The oval orbit repeating every 100,000 years would match the time frame if we did not currently have a circular orbit with only 3% variance iirc and the Holocene is due on the time scale to end, if the last half million years mean anything. Its not set to end you say, yet the pattern of 90,000/11,000 is established. So, while I think Milankovitch might have something to do with climate, I doubt he's the 800 lb gorilla of the 90,000/11,000 cycle. So, that would leave some other pattern or pulse of energy to describe it. Which the sun might be the likely culprit, with some long term pulse that we don't know about. Either that or we get another umpteen years of interglacial, the last half million years be damned, and wouldn't that be nice? The fact remains that the sun's magnetism is going into a huge valley, particularly if solar cycle 25 goes as predicted. The sunspots have tanked. So we're going at least into a minimum, and that means cold. You're describing a circumstance Boots where that is the result, assuming I'm right about CO2 not changing that result much which I think you would say that CO2 is so bad that it won't make much difference.To me a minimum would be much preferred over the end of the Holocene of course.

I'll explain the chart I posted above in more detail. Here's the bottom three plots, with a few lines added by me in Paint. The red line is where we are today, and the time is in thousands of years.

The top plot is the insolation (average amount of sunlight per day) at 65 degrees north, near the Arctic Circle. I drew two horizontal lines: a red one and a blue one. The red line is a (crude) estimate of how high the insolation has to be to end a glacial period near a glacial maximum; the blue line is an estimate of how low it has to be to trigger ice sheet formation in the Northern Hemisphere. The insolation comes from the sum of all of the different Milankovitch cycles. What you'll notice is that the cycles are all roughly canceling each other out in the relatively near future, so that Arctic never gets cold enough to sustain or grow an ice sheet for at least the next 50,000 years. We are currently at a tiny minimum and expect to see Arctic insolation increase slightly from this point out. The overall result is expected to be an unusually long interglacial. Interglacials have been repeating at a roughly 100,000 year cycle, but it's not quite as regular as you think.

The middle plot is a measure of the ratio of oxygen isotopes found in the shells of plankton (benthic foraminifera). It serves as a measure of how much water is locked up in ice sheets, and also, to some extent, how cold it is. I can go into why if you'd like. The peaks are interglacials, and I've drawn magenta lines from the peaks of each of the past 400,000 years to connect them to what the Milankovitch cycles were doing at the time. A couple of things jump out. For instance, the interglacial before last was actually a pair of interglacials with a brief little mini-glacial in between. The Milankovitch cycles at that time were adding to each other and producing more extreme fluctuations, leading to that double peak. You'll also notice that there was a bunch of wobbling around between minor glacial and interglacial conditions 600,000 and 480,000 years ago. Finally, the descent into a glacial period is always slower than the climb out of glacial conditions into an interglacial. So even if we weren't emitting any CO2 and supposing that it really would be cold enough for a glacial period to start, the arrival of the next glacial period would be a fairly slow process.

The bottom plot is from an Antarctic ice core, showing broadly the same patterns as the benthic foraminifera.

I don't want oversell this too much: there's a lot that isn't understood, and it's possible that our notions of how glacial periods start and end is incomplete. What I can tell you is that we wouldn't expect to see a new glacial period, and the sun is not variable enough to throw us into an ice age, especially given the amounts of CO2 we are emitting.

 

[TheMeInTeam]

Have to admit it's been years since I last saw the 'solar cycle' argument.

Solar cycles will be a big deal if we ever make it to other stars at least, especially red dwarfs! Maybe it's forward-thinking after all. Like, really forward thinking.

 

[CavLancer]

Thank you Boots, that took some effort, and I slept on it. So lets say for argument's sake that this time around the interglacial will last, what, almost 3 times as long as it ever has before in the last half million years, I hope so. So we still have a sun that is flat-lining magnetically for whatever reason, all it is is a minimum. A minimum has lowered temps twice, yes? Once by 3C and once by 5C? (been a while) So how does that stack up by the amount AGW has raised temps? The difference should show how much it might cool should this continue, right?

 

[CavLancer]

Just FYI, no proof of cooling but... Snow Hawaii? Yup. ...and if you live on the East Coast of the US, get out your arctic wear. You can expect broken cold records.

 

[Valka D'Ur]

It got cold enough here that I had to put on another layer of clothes... inside. I'm not desperate enough to wear socks indoors, though. Yet.

It's handy, having that vent on my computer where the nice warm air comes out. I can warm my hands up every so often.

 

[CavLancer]

Yes, the cold came through there already, what temp is it outside now, any idea Valka? Plus, it should be evening there, getting colder. Got lots of quilts? I'm sure you are prepared for cold and pipes are insulated or they would be frozen by now...

 

[sophie]

Just FYI, no proof of cooling but... Snow Hawaii? Yup. ...and if you live on the East Coast of the US, get out your arctic wear. You can expect broken cold records.

You do realize the difference between climate and weather, yeah?

 

[CavLancer]

I certainly do. Climate is made up of a lot of weather over a long period of time. I know this thread flys in the face of that but I expect things to get cold enough that the whole question becomes moot. The cold will 'wake people up'. ...or not, if I'm wrong or before my time.

 

[Synobun]

It's quite accepted that changes in climate of the sort we're facing will result in more extreme weather.

It's had a serious snow here for the first time since I've moved to the west coast. I made it a whole two years and a half before needing to deal with this awful creation by the devil again. At least I don't have to shovel anymore.

 

[AppleDumplingHead]

Whether or not humans have a huge hand in the process, it's inevitable that the planet will change, sea levels will rise. What frustrates me is that we don't see world-wide programs for many of these cities/communities which will soon be literally a meter or more underwater in 50 or 100 years. Those people, not just leaders but the citizens themselves, need to be making arrangements to abandon these wide swaths of terrain which simply will not be habitable without a scuba suit.

 

[Berzerker]

http://phys.org/news/2016-12-period-antarctica-planet-average.html

Clow measured twice, once in 2011 and again in 2014, the temperature in a 3.4-kilometer-deep (2-mile-deep) borehole from which the West Antarctic Sheet Divide ice core had been drilled during an eight-year project that ended in 2011. Ice at the bottom of the borehole was deposited about 70,000 years ago; ice about one-sixth of the way up about 50,000 years ago; and ice about one-third of the way to the surface 20,000 years ago.

thats 2 miles of ice thats been building up over 70k and apparently its still piling up... I imagine all that weight spreads glaciers out like squeezing a tube of toothpaste.

 

[CavLancer]

It's quite accepted that changes in climate of the sort we're facing will result in more extreme weather.

It's had a serious snow here for the first time since I've moved to the west coast. I made it a whole two years and a half before needing to deal with this awful creation by the devil again. At least I don't have to shovel anymore.

Right, as the recent snow and hail in Saudi show, the hail in Mexico and Australia. Last year snow in Vietnam, Taiwan...rather think it will snow for the first time ever (human history) in the Philippines before this is over.

Lets see, parts of Asia 50 F below normal, that's what's heading to the East Coast now, record snow in Sweden recently...going to see this stuff where you live.