From the BBC:
"The last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago, when the temperature was 2-3C warmer and sea level was 10-20 metres higher than now," said World Meteorological Organization Secretary-General Petteri Taalas.
Jolly good, let's take that at face value.
What strikes me is that they are always telling us that the CO2 concentration in the air is so high that we have reached, or about to reach some sort of tipping point, a point of no return, irreversible climate change, runaway global warming etc.
So why don't they tell us what happened last time CO2 levels were this high? Did temperatures continue shooting up? According to the long term temperature chart here, nothing much happened and we happen to be near the top of a 100,000 year cycle.
So the next Ice Age will be upon us soon enough. Brrr!
Might As Well Get Them Some Hugo Boss Uniforms, Rowley...
53 minutes ago
30 comments:
That's part of the problem. We are in a cooling phase regards that 100,000 year cycle. Not 'at the top' of the cycle but past it and on the way down.Since about 6000 years already...yet we are warming just as the CO2 concentrations (et al gases) in the atmosphere have increased.
so it would be a bit perverse to just say "well before when the cycle turned down we cooled..." when we've been warming since the industrial revolution. (yes I know, not warming in a straight line...yawn.)
Also those natural climate changes caused by orbit, precession and tilt are quite minor and gradual over thousands of years so nothing like the changes we've seen in the last couple centuries which is all pretty obvious really ...even to flat earthers ;)
PC, if we would have been in a cooling phase then anything that slows or reverses it is to be warmly welcomed!
PC, also, we haven't been warming "since the industrial revolution", we've been warming since the little ice age ended.
Yes we're warming despite Milankovitch. The problem is less the fact there is some warming which we wouldn't otherwise expect rather the rate of warming. And contrary to your suggestion that coolings follow warmings hence no need to worry...previous 'rapid' rates of temperature change, unlike the 'last one' have been synonymous with mass extinctions.
The industrial revolution (2nd half 18thC) had already begun before the little ice age ended (circa 1800).
PC, I checked again, it warmed 1700 to 1800, cooled 1800 to 1900, warmed since 1900. From coldest (little ice age) to warmest (today) is within a 1C band. Were still cooler than mediæval warm period.
Medieval warm period coincides with increased solar activity and low volcanic activity. There was the reverse in the little ice age. Most recent warming is despite Milankovitch and reduced solar activity.Also the rate of warming in recent decades significantly greater than that of the Med' warm period.
PC, I like the way you doggedly stick to the approved script. Everything is natural apart from whatever you say is man made. So there are no natural fluctuations any more. Apart from the ones you say are natural when it suits the narrative.
P156c, at the beginning of the C14th many English noble and royal houses had extensive vineyards. By the end of the century, the average temperature had dropped about 1C and nearly all those vineyards had gone. This shows that England was as warm then as it is now, if not warmer - our current vineyards are all in the south of the UK. Where then were all the fossil fuels being burnt globally that are held to be responsible for our current elevated temperatures and if the climate could cool by 1C then, naturally, why not now?
MW. Let's stick to known facts or at least data and leave the cod psychology where it belongs...or I'll point out that you have made a claim about the little ice age versus the industrial revolution as the starting point for the recent warming era, seen it refuted and promptly sought to obfuscate with a diversion into peaks and troughs of the L.I.A.
Special pleading?
B.
Are you seriously positing vague historical accounts of vineyards as a useful proxy for temperature variations between today and the 15th?
I've seen accounts suggesting wine production today is greater in Britain than at at any time in the past.
Anecdotals about 15th wine production in Britain are not the most reliable way to work out how the average 'global' temperature has changed over the centuries. Rather we need long term records from as many different parts of the world as possible. Historical records do not provide this, which is why scientists tend toward other indicators such as growth bands in trees and corals etc. Solar activity, volcanic activity and such like.
PC, let's agree for the sake of this discussion that all the charts in that link are correct.
Its generally accepted by all climate scientists, regardless of their other opinions on AGW, that only the increase in CO2 since about 1950 could possibly have had any impact on global temperatures, via a greenhouse effect. While the Industrial Revolution was indeed going on in the 19th century, it was in pretty much one country, or small part of the globe, the vast remainder was still living as it had for centuries if not millennia. The CO2 emissions of the UK and surrounding European nations as they industrialised in the 19th century were not sufficient to have any significant impact on global temperatures.
Ergo the vast majority of increases in global temperature from the Little Ice Age to the middle of the 20th century can only be natural in causation. What has happened since 1950 is of course open to debate, but the fact remains we are on a long term natural warming trend anyway - the question is whether there is any man made impact on that trend since c. 1950. Prior to that is universally agreed to be natural in process.
Sobers.
"but the fact remains we are on a long term natural warming trend anyway"
It's not clear to me what 'long term' trend you are referring to.
The trend's relating to insolation,tilt and precession combined, (Milankovitch 100ky) are currently cooling not warming. Though due to the fact these three trends are not currently in sync that cooling trend is quite slight. In terms of the much shorter cycles re solar activity the sun has been in a cooling trend for the last few decades. So despite these mitigating trends we are certainly warming rather quickly. That's not to ascribe cause but as I say you don't specify the "natural long term warming trend" that you speak of.
PC, I did not "make any claims" whatsoever and don't be so cheeky.
The little ice age is the name given to the period when it was colder than now. By definition, things have got warmer since the period when if was colder than now. So what I said is tantamount to saying "it has got warmer since it was colder then now" and that is irrefutably true.
S, nice try, but debating the possibility that all this global warming stuff is exaggerated with PC it about as fruitful as me discussing a user-charge based tax system with you :-)
MW. Nice try. "By definition, things have got warmer since the period when if was colder than now. So what I said is tantamount to saying "it has got warmer since it was colder then now" and that is irrefutably true."
So it was sophistry then? An exercise on wordplay. Glad you admitted that but shame you didn't say so earlier, would have saved us both some time.
Sobers on the other hand has made some straightforward comments which don't appear at all fatuous or facetious. I am asking for some clarification.
Also (for Sobers) although temperature rises are not coincidental with the start of the industrial revolution (as you point out) you presumably accept that increases in CO2 are cumulative. Hence even the lower amounts being pushed into atmosphere are still hanging around a century or so later when the CO2 is really getting ramped up. So not so surprising that temperatures didn't start rising for some time. More so if you consider long term Milankovitch was cooling.(not sure that you do)
PC I stated something that is clearly 100% true. End of.
S, PC has alerted us to one thing, which is that we are at the start of a long-term natural cooling cycle. The past 10,000 years were very stable and relatively warm,being the top of the cycle.
"you don't specify the "natural long term warming trend" that you speak of.!"
I thought I made it quite clear - global temperatures have been rising since the Little Ice Age, thats a clear long term trend. Not an Ice Age length trend, but long term on a human scale. And whatever is driving that trend pre 1950 is entirely natural. And presumably continues today. The question is has the CO2 emitted since 1950 changed that long term upward trend or not?
"Are you seriously positing vague historical accounts of vineyards as a useful proxy for temperature variations between today and the 15th?"
There is nothing vague about the records that survive of things like wine production in the C14th (not the C15th, which I have already pointed out was too cool for wine production). This information survives in things like court records etc. This country has written records of things going back to before the Norman conquest. It's hard fact, not vague anecdotal. And yes, wine production is a useful proxy for temperature. It is obviously easier and cheaper to grow your own grapes than to import wine from abroad, so the cessation of wine production is extremely unlikely to have been a passing fad and extremely likely to have been forced on the English by climate change. Archaeologists have excavated Roman vineyards near York. For grapes to have grown outside that far north shows that the climate must have been warmer than it is today. This is as much evidence as the pine trees that the Hadley Climate Research Unit based their historical climate data on.
"The question is has the CO2 emitted since 1950 changed that long term upward trend or not?"
I think that it hasn't. The science behind the whole "greenhouse gas" theory significantly fails to account, as far as I am concerned, for the relative importance of CO2 compared to water vapour, given by how many orders of magnitude the concentrations of the two gases differ. In addition I am suspicious that the "handy infographic" that the IPCC put out in the early days of its existence, which purports to show the mechanics of the "greenhouse effect" and of which the science behind was questioned on this very blog at the time, has now disappeared.
B, good point re relative concentrations. That diagram has disappeared has it? Hmmm...
Sobers."I thought I made it quite clear - global temperatures have been rising since the Little Ice Age, thats a clear long term trend. Not an Ice Age length trend, but long term on a human scale"
I was curious as to whether you were referring to some natural causal agency or agencies that were driving global temperatures but it appears you are not. Apparently you are just referring to the fact that recorded temperatures have risen in the interim (LIAge to date) hence assumed a 'natural' driver(s) the cause(s) of which have not been offered up.
Well we 'know' with a high degree of confidence that the main forcing mechanism and trend over the last million years in the Earth's climate is the insolation/ tilt / obliquely cycles. This is clearly in a cooling phase albeit a rather weak one. Other shorter term factors like ocean currents and temperatures etc can and will naturally impose themselves on these longer term cycles. Why would anyone even expect straight line trends over periods of hundreds of years duration! We don't even have that in the 2nd half of the 20th and even most of the flat earthers on here don't tend to argue against the overusing warming in that period. (though they were doing just that a few years ago when they insisted temp had stopped rising since the turn of the 21st C) :)
By far the best explanation for the rapid post war warming despite the countervailing Milankovitch and more recent solar cycles is the accumulation of GHgases in the atmosphere. Ie; the do not have to appear en masse at the start of the industrial rev' in order to justify 20thC AGW.
B. Vineyards? :)
1. There are more of them today than ever.
2.Pray tell just how sketchy accounts of vineyards in Southern Britain in thd medieval period including 'one or two' accounts of a couple of vineyards above the Midlands Wash west east line somehow offers better evidence of ***GLOBAL*** temperature variations than ice core meas' / tree ring and coral growth taken extensively from northern and southern hemispheres? :) :)
3. Had you considered social and political developments and how they may have impacted wine production back then? I'm thinking of post medieval preferences for beer over wine... or increased access to wines from France after the marriage of Eleanor of Aquitaine and the English King... or the fact that much of the earlier wine production was in the benedictine monasteries and how the dissolution of same by Henry 8th may have affected production... :)
B. H20.
Water vapour is a feedback not a forcing.
In other words, forcing up (higher temperature) causes a feedback of more atmospheric water vapour. At least you can consider it?
If that is the case you can eliminate narurally occuring increases of water vapour as the driver for global warming.
p156c, I take it your attention was elsewhere during any history lessons you may have attended. Now I have your attention, a short refresher: The post-mediaeval period, during which Henry VIII reigned, was largely the C16th. I am talking about the C14th, two hundred years earlier. So, no the dissolution of the monasteries would have had not effect.
Your lack of interest in history might explain why you think that information from primary sources about mediaeval England is a a lot of "sketchy accounts", whereas information extrapolated from pine trees and ice cores is somehow hard fact. I suppose you thing that the account of the Battle of Hastings is simply a "sketchy account" of how the Normans defeated the English king to take over England.
Yes, there are more vineyards today, so what? it is not the number the counts, it's where they are, compared to where they were. Presumably you think that the archaeologists who excavated the Roman vineyard outside York were somehow anticipating that they would need to make a lot of stuff up because, a few decades hence, the producers of fossil fuels would need it to argue against the crusaders who were defending the world against them. In any case, I just used vineyards as an example. I could have mentioned the Norse colonies in Greenland instead, or is all the huge amount of surviving data relating to them simply sketch accounts, too?
Yes, I'm aware of the argument that the North Atlantic area was an anomaly and the rest of the world was a lot cooler during the "Mediaeval Warm Period", but I've never seen anyone produce any evidence that this was the case.
"Had you considered social and political developments and how they may have impacted wine production back then?"
Yes, in that very comment. Perhaps you would like to read it again.
And finally, H2O. Is it a greenhouse gas or isn't it? If it is, the feedback effect means that it is a much more powerful GHG than CO2, not only because there is so much more of it, but also because of the positive feedback that you mention.
If it isn't then please explain why the weather is warmer when there is cloud cover than when there isn't. You can only "eliminate naturally occurring increases of water vapour as the driver for global warming" if water vapour is not a GHG. Otherwise the feedback effect you describe would occur alongside, not instead of, the forcing effect.
B.History less the issue than logic, me thinks.
You seemed to have missed my point completely...and predictably.
It's not the fact that Henry 8th dissolution of the monastries took place after the period that you spoke of or that E of Aquitaine (before which Bordeaux wines were more or less out of bounds) married 'during' the period that you spoke of rather that a multitude of other factors were or could have been responsoble for what 'you claim' was a plethora of vineyards.2 north of the Midlands that I'm aware of. An inconvenience perhaps? :)
Like beer drinking preferences that were not at play in the MWPeriod. Normans otoh were keen winos SHOCK! Had they nof have been so, would vineyards have been less common? And if so, your sketchy evidence would all but dissappear regardless of temperatures. :)
Changing agricultural practices, changing grape varieties, changing social factors and the wider trade environment have no impact on your assessment...even when pointed out.
We also have little idea how productive the Yorkshire vineyard was and we know of a Derbyshire vineyard in the colder 16th C which proves what exactly? That temperatures never fell after the MWPeriod? ...acording to your logic!
The huge data you refer to on Greenland is joke surely? Viking sagas?! Greenland was named such as a Viking tactic to encourage inward migration. That they eventually starved there was due to their inability and stubborn refusal to live off the sea as the inuit did despite their attempts to aid the Vikings. There was never sufficient agriculture there to support anything more than a small group of settlers. Thus they perished. Unable to overcome their biases. :)
See : https://earthsky.org/earth/greenland-icy-not-green-when-colonized-says-study
You also claim to have seen no evidence that,
"the rest of the world was a lot cooler during the "Mediaeval Warm Period".
1. It need not be 'a lot cooler'. If the whole period from before the MWP to the LIAge was part of a longer term cooling period.
2. Since you sneered at tree ring growth/coral growth along with ice core data in your post why would you recognise such evidence even if you saw it?!
Ref H20. Your last paragraph simply stated can be reduced to "what's the difference between a feedback effect and a forcing mechanism". Look it up! :)
P156c, why do you keep referring to the Mediaeval Warm Periods and then trying to prove it didn't exist, or wasn't actually very warm? Your tactic of simply rubbishing matters of historical record simply because they don't agree with the tenets of your chosen religion are worthy of a Creationist. FYI, there is a huge body of records outside the Viking sagas relating to the Greenland settlements, perhaps you are confusing Greenland with Vinland. Your account of the fate of the Norse Greenlanders hardly chimes with a colony that lasted several centuries.
I didn't sneer at tree ring growth, I just said that it was no better than primary historical records, but perhn beaps that's the same thing in your mind.
If you think my last paragraph can be reduced as you say, then you must have skipped English as well as history lessons. You haven't answered my question: is water vapour a greenhouse gas or isn't it? BTW I already know the difference between feedback and forcing, it's pretty elementary physics.
Did you read the above post-Viking saga research (2015) on the 'not so' Greenland? The one titled "greenland-icy-not-green-when-colonized" :)
Seeing as you have since remarked it's the location of vineyards that is what matters not the number of same. Were you aware of the vineyard in Derbyshire in the somewhat colder (than the MWP) 16th C?
Your question: "is water vapour a greenhouse gas or isn't it?" is a bit of a red herring isn't it? Amounting to, 'there's loads more of it than CO2 so obviously it's loads more important to global warming...innit'...sort of thing. which is why I stressed forcing as opposed to feedback.
"Carbon Dioxide is more Important than Water Vapor as a Greenhouse Gas"
That is what matters and that is what is being taught in universities today across the planet.
"The only practical way we know of to greatly change water vapor in the air is to change the temperature."
"...research has looked at what would happen if carbon dioxide were removed from the atmosphere. Loss of the carbon dioxide cools the planet, but that condenses some of the water vapor, which cools the planet more, and the Earth turns into an ice-covered snowball. If water vapor is removed, a lot more evaporates quickly before the Earth can freeze"
"So, yes, water vapor is blocking more energy than carbon dioxide today. But, carbon dioxide is much more important for changing the climate than is water vapor. CARBON DIOXIDE CAN BE A FORCING—add it to the air, and you FORCE the climate to change. Carbon dioxide ALSO can be a feedback—change something else (such as reducing oxygen in the ocean to allow more fossil-fuel formation), and that changes carbon dioxide in the air, which in turn changes the temperature. BUT, water vapor is ALMOST ENTIRELY A FEEDBACK, because there aren't any natural or human processes other than changing the temperature that can put water vapor up fast enough to make a big difference to climate." ...Emphases all mine. :)
That's what the professors at Penn State University led by Prof Feineman, are currently teaching their undergrads.
https://www.e-education.psu.edu/earth104/node/1262
Moral of this story; Too much interest in history of wine and Viking legends makes for low grades in the sciences!
PC, step outside yourself and view the discussion between you and B objectively.
B makes statements which do not contradict themselves. Instead of making your own statements, you are just accusing him of having said things he didn't, and then criticising him for doing so. (Pretty much the same as what you tried with me until I got bored).
You are not making any case for anything, apart from religiously sticking to The Script that you can pick and choose what is natural and what is man made.
Sorry Mark. Non specifics don't help. B has said an awful lot... Greenland which wasn't so green supports his vineyards baloney. Historical records of a vineyard in Yorkshire and perhaps one other somehow make at least as strong an argument for global temperature proxies as ice core/coral etc records taken from across multiple sites in both hemispheres?! Maybe you're just too used to everyone agreeing with you on AGW.
And the last post was mostly to answer his own confusion on water vapour and CO2.
This site is something of a paradox. It posits heterodox thoughts on the subjects of LVT and CI with a great deal of rigour whilst RELIGIOUSLY adopting every contrarian scientific argument it can dig up on the Web regardless how ludicrous it may be.
Its a bit like a cult on here.
The anti establishment anti mainstream science cult. The
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