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budmantis

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Is AGW Delaying A New Ice Age?
« on: August 27, 2016, 06:41:30 AM »
I think it is safe to say the we on the forum have already come to the conclusion that AGW is for real. For myself, in the early 2000's I thought the deniers were protesting a bit too much, so I considered both sides of the argument and found that AGW was indeed for real. I think the 2007 melting season was the final piece of the puzzle.

I'm someone who is fascinated by extremes. The question on this new thread I'd like to ask is threefold; 1. Are we presently on the cusp of exiting this interglacial and entering into a new ice age? 2. If so, will AGW be enough to prevent a new ice age from happening or at least attenuating it? 3. Is it a good thing or a bad thing, considering that a new ice age would inconvenience a large portion of the population? Thanks to all.
« Last Edit: August 27, 2016, 07:22:56 AM by budmantis »

Darvince

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Re: Is AGW Delaying A New Ice Age?
« Reply #1 on: August 27, 2016, 07:41:07 AM »
1. I've come to the conclusion that we as humans have far more power over the climate than even most of the people on this forum may think. As such, I think we cancelled the start of a new ice age with widespread farming and deforestation across China, India, and Europe and have only solidified that with fossil fuel burning. Were humans to have never started agriculture, the world would be about 1.5C cooler than it is now, and heading into an ice age and cooling significantly.

2. AGW is FAR more than enough to prevent a new ice age, and we may not see another ice age for millions of years unless we take CO2 down to below its preindustrial levels. I bring up a quote from James Hansen -
Quote
Forces instigating ice ages, as we shall see, are so small and slow that a single chlorofluorocarbon factory would be more than sufficient to overcome any natural tendency toward an ice age. Ice sheets will not descend over North America and Europe as long as we are around to stop them.

3. I guess it's a good thing??? I don't really know, a temperature rise of 4C and a temperature fall of 4C are equally horrific. If we do manage to stabilize the level of CO2 below 350ppm then it's definitely a good thing. But 500ppm+ long-term would be just as damaging as reentering an ice age.

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #2 on: August 27, 2016, 08:01:11 AM »
Thanks Darvince. I have a lot of respect for James Hansen, but one factory emitting CFC's is enough to stop an ice age? I think that is a bit of an overstatement but he has a lot more knowledge on the subject than a layman like myself.

One thing I didn't think to add to my question was whether AGW was strong enough to overpower the elements causing global cooling, resulting in continued global warming at a slower pace. At any rate, I find this subject thought provoking. Thanks for your comments. 

oren

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Re: Is AGW Delaying A New Ice Age?
« Reply #3 on: August 27, 2016, 11:31:19 AM »
Thanks Darvince. I have a lot of respect for James Hansen, but one factory emitting CFC's is enough to stop an ice age? I think that is a bit of an overstatement but he has a lot more knowledge on the subject than a layman like myself.

One thing I didn't think to add to my question was whether AGW was strong enough to overpower the elements causing global cooling, resulting in continued global warming at a slower pace. At any rate, I find this subject thought provoking. Thanks for your comments.

What are these elements I wonder? First, looking at the Mean Global Surface Temperatures chart clearly shows that AGW can easily overcome anything thrown in its path. Second, as far as my limited understanding goes, global warming is partly mitigated by aerosol masking, and by volcanoes, both of which put sulfur in the atmosphere. volcanoes are random, but aerosols are a result of pollution, and might go down as a factor in the future, either by China and other polluted countries cleaning up, and/or by civilizational collapse causing a drop in industrial activity.
Global cooling is a term best not used, as it's misleading.

BornFromTheVoid

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Re: Is AGW Delaying A New Ice Age?
« Reply #4 on: August 27, 2016, 02:26:19 PM »
In a sense I guess we have. We've probably prevented the transition into the next glacial phase of this ice age.
Temperatures had been cooling gradually from about 8,000 years ago until the industrial revolution, then suddenly and rapidly reversed.
This cooling was quite gradual, caused by orbital forcing as part of the Milankovitch cycles, but with current and projected CO2 levels it's incredibly unlikely we'll enter another glacial period at all.



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Re: Is AGW Delaying A New Ice Age?
« Reply #5 on: August 27, 2016, 02:44:07 PM »
Thanks Darvince. I have a lot of respect for James Hansen, but one factory emitting CFC's is enough to stop an ice age? I think that is a bit of an overstatement but he has a lot more knowledge on the subject than a layman like myself.

One thing I didn't think to add to my question was whether AGW was strong enough to overpower the elements causing global cooling, resulting in continued global warming at a slower pace. At any rate, I find this subject thought provoking. Thanks for your comments.

Every major ice age that I know of had atmospheric concentrations of CO2 at about 200 ppm.

Next question?

Bruce Steele

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Re: Is AGW Delaying A New Ice Age?
« Reply #6 on: August 27, 2016, 03:06:32 PM »
If we were headed into an ice age because atmospheric CO2 and insolation were dropping and earths temperature was dropping we would know exactly how to reverse the trend. That experiment has already been run, we have results. If on the other hand we wanted to remove 100-200 ppm of extra atmospheric CO2 we would be completely up the creek without a paddle.  We haven't a clue. This little experiment has gone very badly and getting rid of all that extra CO2 is going to take much more energy and effort than humans can ever muster.   Prepare for a hard landing.

Tor Bejnar

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Re: Is AGW Delaying A New Ice Age?
« Reply #7 on: August 27, 2016, 03:31:52 PM »
In support of the several commenters above, here is a summary of a scientific paper on this subject published in 2012 (or maybe 2011) on-line here, I think (but the site is currently down):
Quote
Global warming delays natural patterns of glaciation
By Donna Hesterman

Unprecedented levels of greenhouse gases in the Earth’s atmosphere are disrupting normal patterns of glaciation, according to a study co-authored by a University of Florida researcher.

The Earth’s current warm period that began about 11,000 years ago should give way to another ice age within about 1,500 years, according to accepted astronomical models. However, current levels of carbon dioxide are trapping too much heat in the atmosphere to allow the Earth to cool as it has in its prehistoric past in response to changes in Earth’s orbital pattern.

The research team, a collaboration among University College London, University of Cambridge and UF, said their data indicate that the next ice age will likely be delayed by tens of thousands of years.

The study was published in the journal Nature Geoscience.

That may sound like good news, but it probably isn’t, said Jim Channell, distinguished professor of geology at UF and co-author.

“Ice sheets like those in western Antarctica are already destabilized by global warming,” said Channell. “When they eventually slough off and become a part of the ocean’s volume, it will have a dramatic effect on sea level.” Ice sheets will continue to melt until the next phase of cooling begins in earnest.

The study looks at the prehistoric climate-change drivers of the past to project the onset of the next ice age. Using astronomical models that show Earth’s orbital pattern with all of its fluctuations and wobbles over the last several million years, astronomers can calculate the amount of solar heat that has reached the Earth’s atmosphere during past glacial and interglacial periods.

“We know from past records that Earth’s orbital characteristics during our present interglacial period are a dead ringer for orbital characteristics in an interglacial period 780,000 years ago,” said Channell. The pattern suggests that our current period of warmth should be ending within about 1,500 years.

However, there is a much higher concentration of greenhouse gases trapping the sun’s heat in the Earth’s atmosphere now than there was in at least the last several million years, he said. So the cooling that would naturally occur due to changes in the Earth’s orbital characteristics is unable to turn the temperature tide.

Over the past million years, the Earth’s carbon dioxide levels, as recorded in ice core samples, have never reached more than 280 parts per million in the atmosphere.

“We are now at 390 parts per million,” Channell said. The sudden spike has occurred in the last 150 years.

For millions of years, carbon dioxide levels have ebbed and flowed between ice ages. Orbital patterns initiate periods of warming that cause ocean circulation to change. The changes cause carbon dioxide-rich water in the deep ocean to well up toward the surface where the carbon dioxide is released as a gas back into the atmosphere. The increase in atmospheric carbon dioxide then drives further warming, and eventually the orbital pattern shifts again and decreases the amount of solar heat that reaches the Earth.

“The problem is that now we have added to the total amount of CO2 cycling through the system by burning fossil fuels,” said Channell. “The cooling forces can’t keep up.”

Channell said that the study brings to the forefront the importance of atmospheric carbon dioxide because it shows the dramatic effect that it is having on a natural cycle that has controlled our Earth’s climate for millions of years.

“We haven’t seen this high concentration of greenhouse gases in the atmosphere for several million years,” Channell said. “All bets are off.”

Jim Channell, jetc@ufl.edu

(I found this paper with an internet search.)
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crandles

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Re: Is AGW Delaying A New Ice Age?
« Reply #8 on: August 27, 2016, 05:45:51 PM »
A 2016 paper:

https://www.pik-potsdam.de/news/press-releases/human-made-climate-change-suppresses-the-next-ice-age
Quote
“Even without man-made climate change we would expect the beginning of a new ice age no earlier than in 50.000 years from now – which makes the Holocene as the present geological epoch an unusually long period in between ice ages,” explains lead author Andrey Ganopolski. “However, our study also shows that relatively moderate additional anthropogenic CO2-emissions from burning oil, coal and gas are already sufficient to postpone the next ice age for another 50.000 years.

so to
Quote
1. Are we presently on the cusp of exiting this interglacial and entering into a new ice age?

So even without MMCC, no, unless 50,000 years counts as 'on the cusp'.

2. Yes MMCC is much stronger and faster and even if we stop net emissions soon then a portion of the CO2 already emitted hangs around for a long time and that can be enough to delay next ice age.

3 We need to worry about MMCC much more than whether next ice age will come in 50000 or 100000 years time - who knows what we will be capable of dealing with in 500 years let alone 50,000 years? The next 100 years or two on the other hand does not allow for such a who cares attitude.

While this is a 2016 paper, I don't think it is particularly new. eg
https://en.wikipedia.org/wiki/Orbital_forcing#Overview
references Berger and Loutre, 2002 for 50000 years to next ice age.

Iceismylife

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Re: Is AGW Delaying A New Ice Age?
« Reply #9 on: August 27, 2016, 05:59:49 PM »
1. I've come to the conclusion that we as humans have far more power over the climate than even most of the people on this forum may think. As such, I think we cancelled the start of a new ice age with widespread farming and deforestation across China, India, and Europe and have only solidified that with fossil fuel burning. Were humans to have never started agriculture, the world would be about 1.5C cooler than it is now, and heading into an ice age and cooling significantly.
Does the 1.5C cooler figure include the input from the three volcanic eruptions that cooled us off into the little ice age?  If it doesn't then the figure would be something more like 2.5 C cooler than now.
2. AGW is FAR more than enough to prevent a new ice age, and we may not see another ice age for millions of years unless we take CO2 down to below its preindustrial levels. I bring up a quote from James Hansen -
Quote
Forces instigating ice ages, as we shall see, are so small and slow that a single chlorofluorocarbon factory would be more than sufficient to overcome any natural tendency toward an ice age. Ice sheets will not descend over North America and Europe as long as we are around to stop them.
Maybe. A different way of stating what was quoted is this.  The climate is so unstable that a small input will get large swings in either direction.  So a question that need to be answered is this. Will a large release of fresh water into the North Atlantic overpower AGW?

3. I guess it's a good thing??? I don't really know, a temperature rise of 4C and a temperature fall of 4C are equally horrific. If we do manage to stabilize the level of CO2 below 350ppm then it's definitely a good thing. But 500ppm+ long-term would be just as damaging as reentering an ice age.

We are currently set up to have an ice free planet if we keep this global temp or warmer long term.  No ice in Greenland and no ice in Antarctica.  If we don't want large amounts of sea level rise we need to cool it off from where we are now.

AbruptSLR

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Re: Is AGW Delaying A New Ice Age?
« Reply #10 on: August 27, 2016, 06:11:32 PM »
There are many relevant posts on this topic in the linked "Early Anthropocene" thread:

http://forum.arctic-sea-ice.net/index.php/topic,852.0.html
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budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #11 on: August 27, 2016, 06:16:48 PM »
Thanks Darvince. I have a lot of respect for James Hansen, but one factory emitting CFC's is enough to stop an ice age? I think that is a bit of an overstatement but he has a lot more knowledge on the subject than a layman like myself.

One thing I didn't think to add to my question was whether AGW was strong enough to overpower the elements causing global cooling, resulting in continued global warming at a slower pace. At any rate, I find this subject thought provoking. Thanks for your comments.

Global cooling is a term best not used, as it's misleading.

Why would it be best if the term "global cooling" not be used and why is it misleading? What term would you use to take it's place?
(Note: I am not implying that global cooling is occurring now or will occur any time in the foreseeable future.)

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #12 on: August 27, 2016, 06:48:09 PM »
A 2016 paper:

https://www.pik-potsdam.de/news/press-releases/human-made-climate-change-suppresses-the-next-ice-age
Quote
“Even without man-made climate change we would expect the beginning of a new ice age no earlier than in 50.000 years from now – which makes the Holocene as the present geological epoch an unusually long period in between ice ages,” explains lead author Andrey Ganopolski. “However, our study also shows that relatively moderate additional anthropogenic CO2-emissions from burning oil, coal and gas are already sufficient to postpone the next ice age for another 50.000 years.


 The next 100 years or two on the other hand does not allow for such a who cares attitude.

While this is a 2016 paper, I don't think it is particularly new. eg
https://en.wikipedia.org/wiki/Orbital_forcing#Overview
references Berger and Loutre, 2002 for 50000 years to next ice age.

I appreciate your post, but you seem to be implying I have a "who cares" attitude. I can assure you I don't and I take man made climate change very seriously.






AbruptSLR

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Re: Is AGW Delaying A New Ice Age?
« Reply #13 on: August 27, 2016, 07:08:15 PM »
I appreciate your post, but you seem to be implying I have a "who cares" attitude. I can assure you I don't and I take man made climate change very seriously.

Hansen has indicated that to stay in the climate "sweet spot" CO2-eq should be something below 350ppm (which is higher than pre-industrial but much lower than we are today).

Furthermore, what is important to remember is that paleo-radiative forcing oscillations have been both slow and weak in magnitude, but their effects have been gradually magnified by both positive and negative feedback mechanisms that are not always active.  Thus it is a misconception to believe that there is a strong natural radiative cooling force that AGW must fight against, as currently the majority of positive feedback mechanisms are being strengthened while a great many negative feedback mechanisms are projected to weaken with continued AGW within a few decades.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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crandles

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Re: Is AGW Delaying A New Ice Age?
« Reply #14 on: August 27, 2016, 07:11:18 PM »

I appreciate your post, but you seem to be implying I have a "who cares" attitude. I can assure you I don't and I take man made climate change very seriously.

The don't care attitude I was referring to was what I thought about what happens 50000 years.

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #15 on: August 27, 2016, 07:20:47 PM »
Got it. Thanks!

mati

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and so it goes

Iceismylife

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Re: Is AGW Delaying A New Ice Age?
« Reply #17 on: August 27, 2016, 09:38:06 PM »
Thanks Darvince. I have a lot of respect for James Hansen, but one factory emitting CFC's is enough to stop an ice age? I think that is a bit of an overstatement but he has a lot more knowledge on the subject than a layman like myself.

One thing I didn't think to add to my question was whether AGW was strong enough to overpower the elements causing global cooling, resulting in continued global warming at a slower pace. At any rate, I find this subject thought provoking. Thanks for your comments.

Global cooling is a term best not used, as it's misleading.

Why would it be best if the term "global cooling" not be used and why is it misleading? What term would you use to take it's place?
(Note: I am not implying that global cooling is occurring now or will occur any time in the foreseeable future.)
Too many denialists  around.

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #18 on: August 27, 2016, 11:02:49 PM »
Thanks Darvince. I have a lot of respect for James Hansen, but one factory emitting CFC's is enough to stop an ice age? I think that is a bit of an overstatement but he has a lot more knowledge on the subject than a layman like myself.

One thing I didn't think to add to my question was whether AGW was strong enough to overpower the elements causing global cooling, resulting in continued global warming at a slower pace. At any rate, I find this subject thought provoking. Thanks for your comments.

Global cooling is a term best not used, as it's misleading.

Why would it be best if the term "global cooling" not be used and why is it misleading? What term would you use to take it's place?
(Note: I am not implying that global cooling is occurring now or will occur any time in the foreseeable future.)
Too many denialists  around.

Care to elaborate?

sidd

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Re: Is AGW Delaying A New Ice Age?
« Reply #19 on: August 27, 2016, 11:15:30 PM »
I must recommend Ruddiman's work in this context.

Iceismylife

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Re: Is AGW Delaying A New Ice Age?
« Reply #20 on: August 27, 2016, 11:37:11 PM »
Thanks Darvince. I have a lot of respect for James Hansen, but one factory emitting CFC's is enough to stop an ice age? I think that is a bit of an overstatement but he has a lot more knowledge on the subject than a layman like myself.

One thing I didn't think to add to my question was whether AGW was strong enough to overpower the elements causing global cooling, resulting in continued global warming at a slower pace. At any rate, I find this subject thought provoking. Thanks for your comments.

Global cooling is a term best not used, as it's misleading.

Why would it be best if the term "global cooling" not be used and why is it misleading? What term would you use to take it's place?
(Note: I am not implying that global cooling is occurring now or will occur any time in the foreseeable future.)
Too many denialists  around.

Care to elaborate?
There are a bunch of people running around on the internet that will latch onto anything resembling a statement that it isn't warming up but cooling off.  Commonly called denialists.   They call the other side AGW alarmists. Most of the people on this forum are AGW true believers.

Severity and consequences.  There is the Younger Dryas to think about. And that we should be heading off into an ice age.  The current conditions in the Arctic are set to have more bottom water generated this winter. We are over turning the water column.  This is just opinion on my part but we should see more melting in the glaciers bottom side that are below sea level with the correct bathometry.  The sills around the glaciers need to at greater than 250 meters depth.  If this is the new normal for Arctic conditions then accelerated ice loss though calving is in order.  This is because the water that is going into bottom water tends to get replace by midlevel Atlantic water.  But there are people that are more knowledgeable than I on this subject.

My opinion is that warming is under estimated, sea level rise is under estimated, ice loss from Greenland is way under estimated.  Shutting down or slowing the hyaline circulation is way under estimated, and the result of all this is, coming global cooling.

How long can cyclones keep the Arctic ocean partly ice free?  How much bottom water will be generated?

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #21 on: August 28, 2016, 12:23:00 AM »
I must recommend Ruddiman's work in this context.

Noted. Thanks Sidd.

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #22 on: August 28, 2016, 12:28:45 AM »
Iceismy life:

Thanks for taking the time to explain your comment. I have only a very basic concept on what you discussed. I'm going to take some time to think on what you said and I'm also going to look into Ruddiman's work, per Sidd's suggestion.

sidd

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Re: Is AGW Delaying A New Ice Age?
« Reply #23 on: September 05, 2016, 11:09:05 PM »
Prof. Ruddiman has kindly posted  a comment on the unforced variations september thread at realclimate regarding the early onset of industrial-era warming (  doi:10.1038/nature19082 ) in the light of his own work.

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #24 on: September 06, 2016, 07:35:38 AM »
Prof. Ruddiman has kindly posted  a comment on the unforced variations september thread at realclimate regarding the early onset of industrial-era warming (  doi:10.1038/nature19082 ) in the light of his own work.

Thanks Sidd for bringing Professor Ruddiman to my attention. I've included an article discussing the "Ruddiman hypothesis", which asserts that human activity centuries before the industrial revolution had an impact on the climate. I'd like to see more comments on this thread and would encourage all the lurkers out there to de-lurk and share your thoughts on this subject. Your comments are most welcome!

sidd

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Re: Is AGW Delaying A New Ice Age?
« Reply #25 on: September 06, 2016, 07:17:48 PM »
Here are some papers.

Ruddiman 2003, Climatic Change 61: 261–293, 2003 (i dont have a doi for this)
Ruddiman 2010 doi: 10.1126/science.1188292
Ruddiman 2011 doi: 10.1177/0959683610387172
Ruddiman 2013 doi: 10.1146/annurev-earth-050212-123944
Ruddiman 2014 doi: 10.1177/2053019614529263
Ruddiman 2016 doi: 10.1002/2015RG000503

His books are very good, too.

sidd

Archimid

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Re: Is AGW Delaying A New Ice Age?
« Reply #26 on: September 07, 2016, 04:09:48 PM »
Quote
Is AGW Delaying A New Ice Age?

No it is not. I get this understanding from my favorite climate change graph, AllPalaeoTemps(first attachment). Please notice the change in scale as it approaches the present.

If you define ice ages as the low points of the last million years and interglacials as the peaks over the same period then there is absolutely no way (unless the tilt and wobble of the earth are drastically altered by the changes in water weight distribution) that human induced climate change will prevent the next ice age. We could release all fossil fuels remaining into the atmosphere if you want. In 10k years all that will be back on the ground. Changes in earth orbit and behavior will force an ice age on us.

 If you were to travel 135k years into the future to the next interglacial and make the AllPaleoTemps graph it would look  strikingly similar to this one. Just one more tick after the peak we call the Eemian. I would imagine that the last tick would look slightly different, with two temperature peaks.  One peak at the beginning of the interglacial, that represents the natural warming that led to the interglacial, and another peak at the end, that represents AGW. Regardless, both peaks will ultimately be overpowered by the Milankovitch cycles.

I would like to emphasize that the next ice age is of no concern to either me or many generations after me. Human induced global warming is. To be fair, very rapid melting of the ice caps could cool the oceans enough to precipitate a very temporary ice age, but by that point, who cares.

I am an energy reservoir seemingly intent on lowering entropy for self preservation.

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #27 on: September 07, 2016, 04:11:07 PM »
Thanks Sidd. I plan on reading up on Prof. Ruddiman.

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #28 on: September 07, 2016, 04:32:00 PM »
Quote
Is AGW Delaying A New Ice Age?

 If you were to travel 135k years into the future to the next interglacial and make the AllPaleoTemps graph it would look  strikingly similar to this one. Just one more tick after the peak we call the Eemian. I would imagine that the last tick would look slightly different, with two temperature peaks.  One peak at the beginning of the interglacial, that represents the natural warming that led to the interglacial, and another peak at the end, that represents AGW. Regardless, both peaks will ultimately be overpowered by the Milankovitch cycles.


Great post Archimid. I've attached a description of Milankovitch cycles from Wikipedia.

sidd

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Re: Is AGW Delaying A New Ice Age?
« Reply #29 on: September 07, 2016, 09:33:36 PM »
http://www.nature.com/climate/2008/0812/full/climate.2008.122.html

An older article, but rather good.

"But according to simulations by Archer and others, it would take hundreds of thousands of years for these processes to bring CO2 levels back to pre-industrial values"

" Even with the amount of CO2 emitted so far, another ice age will almost certainly start in about 50,000 years. But if we burn all remaining fossil fuels, it could be more than half a million years before the Earth has another ice age, Archer says. "

Archer here is David Archer. I attach fig 1 from the article. I have posted some later references from the Early Anthropocene thread.

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #30 on: September 17, 2016, 07:57:11 AM »
Here's an early 2016 article discussing how global warming has delayed the next ice age.

http://www.bloomberg.com/news/articles/2016-01-13/the-good-news-on-global-warming-we-ve-delayed-the-next-ice-age

This type of article can no doubt be used as justification for a continuation of using fossil fuels by some. I just want to state for the record that is not my intention.

wili

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Re: Is AGW Delaying A New Ice Age?
« Reply #31 on: September 18, 2016, 12:07:28 PM »
bud: Recall that CFC's are some 10,000 times more powerful as greenhouse gasses than CO2 is. So if Hanson had said that it would only take 10,000 carbon burning plants to prevent the next ice age, would that have been more believable to you?

arch: You are perhaps forgetting feedbacks. If our warming triggers a slow release of seabed methane, you could easily extend the period of warming by thousands to tens of thousands of years. Meanwhile, of course, the sun continues to get (very slowly) warmer.

Of course, these are long past when any of us will be around. But still worth thinking about. It's all ultimately what story we can tell ourselves with some level of probability about what  our legacy to the living planet will be.
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budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #32 on: September 18, 2016, 03:25:47 PM »
bud: Recall that CFC's are some 10,000 times more powerful as greenhouse gasses than CO2 is. So if Hanson had said that it would only take 10,000 carbon burning plants to prevent the next ice age, would that have been more believable to you?


Wili: You are referring to reply #2 dated 8/27/16. The idea of one CFC plant producing the same amount of greenhouse gasses as 10,000 carbon burning plants does seem farfetched to me. In the ten years or so that I have been following the subject of global warming, CO2 and CH4 have been mentioned the most. On this subject, Hanson and many folks on this Forum know a lot more about this than I do. So do I believe it? Yes, but I want to read up on this subject further.

S.Pansa

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Re: Is AGW Delaying A New Ice Age?
« Reply #33 on: September 18, 2016, 06:06:39 PM »
bud: Recall that CFC's are some 10,000 times more powerful as greenhouse gasses than CO2 is. So if Hanson had said that it would only take 10,000 carbon burning plants to prevent the next ice age, would that have been more believable to you?


Wili: You are referring to reply #2 dated 8/27/16. The idea of one CFC plant producing the same amount of greenhouse gasses as 10,000 carbon burning plants does seem farfetched to me. In the ten years or so that I have been following the subject of global warming, CO2 and CH4 have been mentioned the most. On this subject, Hanson and many folks on this Forum know a lot more about this than I do. So do I believe it? Yes, but I want to read up on this subject further.

Add to the subject of GWP of CFCs .... A good starting point for further reading migth be IPCCs AR4: The Physical Science Basis, 2.10.2 - Direct Global Warming Potentials, especially page 212-13.

Definitely some nasty HFCs & PFCs amongst them:
- PFC-14 with a GWP (100) of 7,390 and a lifetime of ~50,000 years or instance;
- or Sulphur hexafluoride  with a GWP (100) of 22,800 & a lifetime of 3,200 years.  :o

budmantis

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Re: Is AGW Delaying A New Ice Age?
« Reply #34 on: September 18, 2016, 07:25:43 PM »
bud: Recall that CFC's are some 10,000 times more powerful as greenhouse gasses than CO2 is. So if Hanson had said that it would only take 10,000 carbon burning plants to prevent the next ice age, would that have been more believable to you?


Wili: You are referring to reply #2 dated 8/27/16. The idea of one CFC plant producing the same amount of greenhouse gasses as 10,000 carbon burning plants does seem farfetched to me. In the ten years or so that I have been following the subject of global warming, CO2 and CH4 have been mentioned the most. On this subject, Hanson and many folks on this Forum know a lot more about this than I do. So do I believe it? Yes, but I want to read up on this subject further.

Add to the subject of GWP of CFCs .... A good starting point for further reading migth be IPCCs AR4: The Physical Science Basis, 2.10.2 - Direct Global Warming Potentials, especially page 212-13.

Definitely some nasty HFCs & PFCs amongst them:
- PFC-14 with a GWP (100) of 7,390 and a lifetime of ~50,000 years or instance;
- or Sulphur hexafluoride  with a GWP (100) of 22,800 & a lifetime of 3,200 years.  :o

:o Indeed! Thanks S. Pansa! The most important lesson I've learned in life is that the learning never ends.

jai mitchell

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Re: Is AGW Delaying A New Ice Age?
« Reply #35 on: September 18, 2016, 07:34:56 PM »
According to the changes in northern hemisphere solar forcing due to the Milankovitch cycles and the trend line of early CO2 abundance reductions, we were supposed to be well within an Ice Age about 2,000 BCE.  However, if we had not, making this current interglacial event one of the very longest in the ice core record, then certainly it would have occurred as a result of volcanic eruptions in the 6th century, pushing the northern hemisphere into glacier nucleation with decreased albedo driving further cooling and CO2 reductions.

http://www.sciencemag.org/news/2016/02/volcano-induced-little-ice-age-may-have-contributed-famines-wars-6th-and-7th-centuries
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johnm33

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Re: Is AGW Delaying A New Ice Age?
« Reply #36 on: September 18, 2016, 11:18:33 PM »
That 536ad date [in jais link]  is an exact match for the comet that laid Britain to waste in the time of King Arthur, according to V Clube and B Napier in 'the cosmic serpent', and brought on the Dark ages. This doesn't get a mention by mainstream historians, the coincident Justinian plague laid waste to the failing roman empire, the majority of slaves starved. According to some 'alternative' historians, who do include this event in their accounts the population of britain went from somewhere between 12-15 million to +/-500,000 in just over a decade and opened the country up to centuries of raids which it was too weak to resist. Reputedly as the 'comet' passed over all the forests burst into flame and the fire could be seen from France. A fragment of the 'comet' landed in Bolivia iirc.