[mikewonders]

The relevance is that the behavior of temperature and CO2 over the last 20,000 years was pretty much the same as in previous rapid-rise phases of the 100,000 year cycles.

Mmmmm, it seems to me looking at the scales of CO2 / temperature graphs on Earth.org or others, that while the levels may suggest similarity, the chronological index scale appears to change in the different sections. i.e. the Rate of Change is much slower in the past but for the time scale making it appear more similar.  The point being made is that there has NEVER been a time in any length of history or prehistorical record where the changes in both temperature and CO2 have risen at this rate of change, indicating a much more potent and relative immediate force multiplier (possibly water vapor) AND rate of CO2 production, e.g. man made generation / causes of CO2 emission / climate forcing.

so it makes sense to ask what has been going on, and why the cycles have been so similar despite what you assert to be fairly chaotic surface conditions.. This might just give us an inkling of what will happen if and when we reduce anthropogenic CO2 production.

Personally, I don't see them being similar due to the ROC noted above.  I see the current changes as fully anomalous relative to all other historical records, again a matter of context leading to cause and effect.  We always want apples / apples or a means to get to that relevance.  I don't see a way to get to that relevance in this case.

 
We know that the planet was warmer 500 years ago than it is now, so we can either dismiss anthro-CO2 as a cause, or write off recent measurements as "noise" on a much more powerful wave driven by something else. It would be illogical to do neither.

The temperature chart on Earth.org suggests the planet was NOT warmer 500 years ago.  In fact, unless I'm mis-reading or making a mistake in reading their temperature history, the planet has not seen these temperatures for more than 100,000 years during the mid pleistocene period.

Either way, we cannot or are not recreating the context, cause or effect of the past and any action we take will be equally or more anomalous by comparison to historical events.

I'm trying to understand how you're drawing the conclusions that the premise of 3 or 4 questions can somehow prove or disprove past cause/effect relevance to current and future cause / effect or remedial efforts. 

I might be thick headed and stuck inside the perspective I'm holding and just unable to make the connection you're suggesting but to my way of thinking context and rates of change are incredibly important to understand such a diverse dynamic.  I don't see a "simple" path to estimate results of future change without those apples to apples.

The one thing I see in common is the concern that altering CO2 alone may not have sufficient effect, whereas water vapor emission mitigation and redistributing water back to ecologically restored locations and conditions over time could have a far more effective outcome in combination with CO2 and Methane mitigation.  To that extent I wish I could see how you draw your inference in the questions to help support or defer that, but I can't get the apples to work.

[alancalverd]

The point being made is that there has NEVER been a time in any length of history or prehistorical record where the changes in both temperature and CO2 have risen at this rate of change

Back in the days of green cathode ray oscilloscopes we used to call the irreducible small amplitude noise "grass" - very high frequency, very short duration fluctuations of no real consequence to the overall system.

Current weather reporting is done on a 20 minute cycle, and believable estimates of world climate only date from about 1970 with the advent of satellite monitoring, but the prehistoric record is sampled at something like 1000 year intervals, over which any grass looks more like green paint. My inclination is therefore to deduce the underlying mechanism from the "naturally smoothed" data  rather than "adjusted" recent estimates. If that showed clearly that CO2 was the driving and not the driven parameter, there might be some hope of preventing a humanitarian disaster by closing Indian and Chinese manufacturing industry and not using concrete, but it doesn't seem to be the case. Which is why we need a Plan B.

[Bored chemist]

but the prehistoric record is sampled at something like 1000 year intervals,

No, it's annual snow layers.
Or, if you prefer, there's no data with a better finesse than 1000 years. In which case there's no evidence that the temperature rise precedes the CO2 rise.

[alancalverd]

The temperature chart on Earth.org suggests the planet was NOT warmer 500 years ago.

The discovery of 500-year-old plants in the basin of a retreating Canadian glacier suggests that the glacier wasn't there 500 years ago. The Medieval Warm Period is well documented in European history, as is the sudden appearance of indoor fireplaces and chimneys in the 13th century.

I don't know of any agreed international temperature scale or measurements of the temperature of the Pacific Ocean dating back to 1700. Where did earth.org get its data from?

[alancalverd]

No, it's annual snow layers.
Or, if you prefer, there's no data with a better finesse than 1000 years. In which case there's no evidence that the temperature rise precedes the CO2 rise.

I stand corrected. I don't have access to the raw data and I can't interpolate the published graphs to better than 1000 years. Would be grateful for a reference to the good stuff.

[alancalverd]

I often hear from those who question the importance of climate change that reducing carbon dioxide (CO2) emissions into the atmosphere will have little effect, since water vapor is the predominant greenhouse gas. If so, why bother so much about CO2 and other greenhouse gases?

Because we can.

[Bored chemist]

don't have access to the raw data

And yet you keep arguing against the view of those who do.

[mikewonders]

I often hear from those who question the importance of climate change that reducing carbon dioxide (CO2) emissions into the atmosphere will have little effect, since water vapor is the predominant greenhouse gas. If so, why bother so much about CO2 and other greenhouse gases?

Mostly its "believed" because the two work in lock-step forced amplification of reinforcing feedback effects across multiple domains.  They're both contributors in their own right, but when combined the effects of trending increases in atmospheric water vapor / density have enhanced the effects of increasing thermal emissions from growing CO2 by as much as double.

Recent developments by NASA and partners in newly applied satellite analysis are giving a much higher level of accuracy and certainty given alternate / multiple measurement methods to evaluate this very complex concern.  Not only is there complexity in offsetting effects and gradients of both temperature and density per elevation, but the nature of greenhouse is a "reverberating" effect of light/heat wave reflection, reflecting residual reflection, reflecting residual reflection, and so on.

There also remains a portion of increased ocean volume increase which is not yet fully accounted for.  The increase in ocean volume "can" have a driving effect on weather and energy distribution as an increased heat sink storing long term, slow acting thermal storage.  Admittedly as ocean volume expands due to warming it also becomes less dense, so even this is a difficult effect to fully quantify or qualify relative to related effects like evaporation, erosion, etc.  Much of this is part of what we have seen as relatively stable cycles between systems yet it seems among all of it, there is rapid rate of change in weather and temperature suggesting probability of more serious outcomes. 

Then again are we over-stating a natural phenomena that may have occurred without human cause?  The rate of change would suggest not, but that's "belief" versus fact until it can be proven in one or more ways, hopefully to err on the side of caution I suppose.

At least it's finally being looked at more fully and seriously.  I can't say this is a qualified answer but as best I can tell, it points toward greater awareness that helps guide more critical discovery and analysis.

As one looks back across this thread it looks a bit crazy from a distance, but in reality each comment offered by each respondent holds a degree of merit in one way or another, a testament to how complex the question of water vapor as a driver of warming really is.  The more we learn the more we might understand if there is a justifiable seriousness and if so, is it possible to reverse the effects timely to avoid further risk.

[mikewonders]

No, it's annual snow layers.
Or, if you prefer, there's no data with a better finesse than 1000 years. In which case there's no evidence that the temperature rise precedes the CO2 rise.

I stand corrected. I don't have access to the raw data and I can't interpolate the published graphs to better than 1000 years. Would be grateful for a reference to the good stuff.

Not sure about source data on ice cores.  I would guess that may mean searching out closer to the ice core analysis teams that actually collated the sampled data.  It's pretty specialized and narrow focused due to the extremes of exposure to gather samples.  It looked like there was also additional correlation from other sources in the longer prehistoric estimates besides just ice core alone.  I didn't do any background on Earth.org, but only to try to understand your suggestions and visualize context on the prehistoric scale.

[mikewonders]

but the prehistoric record is sampled at something like 1000 year intervals,

No, it's annual snow layers.
Or, if you prefer, there's no data with a better finesse than 1000 years. In which case there's no evidence that the temperature rise precedes the CO2 rise.

Agree, it's likely ice cores and even annual snow layers they include won't afford granularity that would permit a means to determine leading / lagging effect.  I could be wrong about that, but it would seem that way.  They might "infer" it could but probability of confirmation would remain uncertain.  It also would not confirm if cause / effect back then is relevant to cause / effect today by the same metrics which again hints at chronological context.

[alancalverd]

As the historic record clearly shows a lag, then any assertion that CO2 is the principal present-day driver demands an explanation of what has changed, and when. The sudden temperature rise that began about 20,000 years ago looks no different from those that preceded it every 100,000 years, so whatever new physics is required must have occurred within recorded history.

[Petrochemicals]

The temperature chart on Earth.org suggests the planet was NOT warmer 500 years ago.  In fact, unless I'm mis-reading or making a mistake in reading their temperature history, the planet has not seen these temperatures for more than 100,000 years during the mid pleistocene period.

These are quite good graphs,

EPICA_temperature_plot.svg.png (188.14 kB . 2560x960 - viewed 2039 times)
This one shows the variance in temperature and the refinement in readings, the graph becoming sparcer as you go further back in time. Many variances are there at the present era but 400,000 years back it is very sparce.


Holocene_Temperature_Variations.png (51.53 kB . 600x400 - viewed 2156 times)

This is the eera of the last 10, 000 years shown on the previous graph as the smudge at the top of the peak on the right. Taken in context the temperature has been stable for 10,000 years. Unfortunately we are about to fall of a cliff edge.

I often wonder whether it is temperature or man's scientific methods that is the difference between readings. The tri state tornado of 1925 was thought
To be an exaggeration as nothing happened like it for almost 100 years, yet in the midst of global warming it has only just been replicated in a some what similar fashion in December. More hurricanes are recorded now than ever before, some  scientific fields that may be judged as better detection.

[Bored chemist]

As the historic record clearly shows a lag, then any assertion that CO2 is the principal present-day driver demands an explanation of what has changed, and when. The sudden temperature rise that began about 20,000 years ago looks no different from those that preceded it every 100,000 years, so whatever new physics is required must have occurred within recorded history.

And again. We are talking about the very sudden rise that has happened in the last 200 years.

[mikewonders]

As the historic record clearly shows a lag, then any assertion that CO2 is the principal present-day driver demands an explanation of what has changed, and when. The sudden temperature rise that began about 20,000 years ago looks no different from those that preceded it every 100,000 years, so whatever new physics is required must have occurred within recorded history.

And again. We are talking about the very sudden rise that has happened in the last 200 years.

Agree...  Part of the problem appears to be the variations of graphical depictions and how charts index their time line between prehistoric glacial periods versus current time line in the same tracing.  Again, raw data would be most helpful but that search is yet another rabbit hole.

I've looked at several ice core raw data resources.  So far its hit-n-miss on finding raw data with a lot of 404 errors where there should be a data resource.  Then comes the effort to identify which data sets are relevant and if they contain temperature, CO2 and other values of measured input.

Unable to qualify the data or publications for bias, I've trusted NOAA in this instance to summarize some of what Alan is asking, which others have commented to as well.  Glacial and Inter-glacial cycles have a ~100K year periodicity with a max and min structural consistency.  Not wanting to plug the thread with a ton of redundant quotes, the bottom line suggests a combination of ice-albedo dynamics in sync with solar radiation and earth orbit long term cycles.  This would make sense given an envelope of total entropy in cyclic change we would see major consistent peaks and valleys intermixed with other lesser contributing peaks and valleys bound in synchronous drivers.  The limiting factors of both range and frequency periodicity would be a net effect of change inside that total envelope and should be cyclic owing to total reaction potentials in flux, running to limit and reverberating back.

Oceanic CO2 cycles mixed into the major peaks and valleys integrates how natural ice-sheet albedos work in lock-step as part of "natural" CO2 cycles having consistent range amplitude and frequency periodicity.  This is likely how science first ended up considering CO2 as a climate driver, but for the fact it is more likely a secondary component in nature (driven), a more primary component man made (driver), last two centuries. 

CO2 may be driven in both instances but behaves also as a driver in the positive feedback portion of increasing atmospheric water vapor / density, where NASA is starting to confirm values indicating this potential of water vapor to play a role in warming as much as double the causal effect over and above natural albedos. CO2 and water liquid and vapor may actually share or trade motivating influence depending on phase, location and conditions.

I wish the forum would preview inline image inserts during edit.  I'm trusting the image insert function to show the long term cyclic values on prehistoric timeline, borrowed from https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwi_sfKE9I31AhVPLs0KHTRiDvkQFnoECA4QAw&url=https%3A%2F%2Fwww.ncdc.noaa.gov%2Fabrupt-climate-change%2FGlacial-Interglacial%2520Cycles&usg=AOvVaw3l5blUHykjkOxeZ9zbVlrH [nofollow]...


LongCycleIce.png (165.81 kB . 576x325 - viewed 2312 times)

I would encourage anyone unfamiliar with these cyclic events to check out the link.  Maybe that PDF from NOAA helps answer some of Alan's questions about repeating cycles, max and min ranges repeating, etc.  It helped me understand where Alan was coming from and also explains the fast rise time versus more gradual down slope mechanics.

Next, the question of visual integrity of graphing scales ...  Scaled to long term cycles with more recent ice core data being aged, the more immediate short term consequence of heating and CO2 frequently is hidden inside that larger range.  The chart below, (borrowed from https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide [nofollow] gives a much more prudent transition of prehistoric with fairly current indication of CO2, spiking WELL ABOVE prehistorical values, suggesting an on going extremely anomalous CO2 condition in recent perspective, e.g. BC reiterating 200 year window.


LongShortCycleIce.png (131.14 kB . 620x531 - viewed 2228 times)

I think most here understand the current CO2 values have greatly exceeded past historical which is why there is a concern and a tendency to lean on CO2 being causal.  This chart in particular gives a more striking view of the current value at 412 PPM in perspective of prehistorical normal cycles and prior long term historical high of 300 PPM.

From here, I refer next to NASA's recent past and current evaluations starting to favor toward water vapor.  There is some chronological benefit to seeing how NASA has published over time and compensated with increased instrumentation and methods...

https://www.nasa.gov/topics/earth/features/vapor_warming.html [nofollow]
https://earthobservatory.nasa.gov/features/Water [nofollow]
https://earthobservatory.nasa.gov/features/WaterVapor/water_vapor.php [nofollow]

Among those links NASA is starting to lean toward water vapor and seems for the most part not overly laden with bias to the extent we can know it. 

Lacking fuller access to raw data for ice core or satellite data, I continue to lean toward the greater weight of influences of data shown, suggesting higher probability of anthropogenic cause at the heart of the more recent and highly anomalous portion of the CO2 / thermal increase above and beyond the normal ice flow prehistorical records.  Given data showing that atmospheric water volume and density have been on the rise including the increased dimension of the troposphere due to warming, we know more water by volume is stored in increased temperature as well during this period.  This matters on any percentage due to amplification and the fact that water vapor itself is the greater greenhouse reflection even before it's effects on CO2 reflection.

The second link in particular makes a nice stab at estimating where global water resides and may give a sense of how anthropogenic behavior has altered distribution / redistribution of water from land based saturation / deep storage to greater oceanic accumulation.  Despite vapor condensation translation being what appears to be less than 3% volumetric change in ocean levels over the last century, ANY increase in heat sink long term stability via increased ocean mass is not desirable in the given thermal context.  Neither is it desirable to have the highest concentration of residential society concentrated near shorelines being flooded to force inland migration over the next 50 years or more.

Redistribution of water volumes from land based to oceanic accumulation could push (add to) the liquid net 3% vapor translation to a much higher total water redistribution as yet another larger contribution to oceanic volume.  i.e. further heat sink accumulation altering the dynamics of cyclic shift and albedo repeatability.  Population and deforestation / desertification being lesser known metrics compared with prehistoric uncertainty, particulate emissions, evaporation rates, cloud seeding, weather shifts and redistribution of precipitation affecting polar versus equatorial balance and distribution of both water volume and overall weather energy kinetics or potentials.

As a desire to err on the side of caution, there is a risk if we try to grossly influence away from fossil fuels lacking a more global and sensible approach to include the ramifications of depleting oil and gas reserves.  The economics tied to fossil fuel and energy production demand that any transition needs to include and protect those huge corporate interests.  This may reinforce the ability to redesign combustion in renewables to sustain the high demand for combustion related reliability next to intermittent solar / wind and others.  Recent estimates suggest a 50 year capacity remains for crude and natural gas which is greatly in question, but for certain increases in cost dramatically to seek fuller oil reserve tapping due to constraints of depth and hydraulic elevation of crude by water / polymer infusion.  There is a theory that deeper crude production may be a real-time perpetual source.  While this may have some truth to it, the nature of those deeper values is showing to be far more toxic in undesirable fractions and again still more costly and ecologically risky to extract.  If we can afford to do that, can't energy consortia in stead help re-tool away from fossil at a far more cost effective long term renewable method?  This would extend the life time of fossil values for other less damaging uses where petrochemical applications are still very much necessary.

If past behavior is any indication of future outcome, there is no denying that recycling is a profound failure simply on oceanic plastics and single use polymer applications alone.  We were sold a bill of goods and the balance continues in land fill accumulations, methane releases and unfettered oceanic accumulation impacting the most important food source the ocean provides us.  There was a time before man stepped foot on the moon, that our orbital space was pristine.  If we consider the volume of space junk being tracked today in low earth orbit, it should remind us one day it may not be possible to escape low earth due to space debris in any given path of exit.  We knew this before we caused this and yet we continue to add to the problem.  How well are we likely to succeed then in colonizing mars long term if we've not learned to protect our own domain from our own causes first?

We do also risk creating a better world for no good reason if the future were to judge us in this light.  Then again should we question the values of being good stewards to the world we've grown up in being worth that risk of wasted effort if doing so included to sustain economic balance?  That needs to include the considerations of population increase and how hard it is to educate on a global scale inside an efficient time frame relative to impending risk.  Asking parents to create less children or even to permit shorter life spans to encroach is a difficult imposition we're seeing in such ventures as gain of function in the gamble of virus manufacturing. 

Consensus might not be fact, but the days of the original flat earth fears have hopefully given way to a more intelligent scientific means to measure consensus against probability to a greater value in the absence of an ability to assemble fully supported facts and the intricacies of a concern this complex.  I'm not sure there is a more practical alternative to consensus in such complexity in a shorter time frame as time moves forward.

Once again, having fostered the question here originally...  Why can't water vapour be the driver of today's climate change?

I'm not convinced we've ruled out the possibility that water vapor doesn't have a principle role among others making it at least one of the drivers if not even a leading driver forcing the effects of CO2 to be far more accelerated.  There have been some very interesting and valuable inputs here from others to that question both for and against giving value to debate.  Do we really find that CO2 alone (and the means to mitigate its production) are sufficient in common sense to be all the eggs in one basket we need or want to rely on?

I still have not completed the PDF on fossil consumption projections, but the more I've looked at other's data the more I think that may be an exercise in futility given increased findings and data becoming more supportive beyond the limited means of a few in a forum.  Clearly the scientific community is not done with this question yet, which can't hurt.

I at least wanted to bring some fuller references of indicators to consider here as the thread calmed down in debate and competing offers.

Unfortunately we lost a family pet this morning after several days of treating an age related cause ending our seven years with a pet pigeon we rescued that long ago, putting a damper on new years for the family.  He was a friend to our parrot and family we all grew quite fond of.  I likely will not be participating here over the remainder of the holiday, but to say thank you to each for adding consideration to the question. 

Best wishes for a new year to each.

[walnutclose]

That's a very pretty absorption spectrum of a sample of CO2, and there's no disputing that it looks like it should. But what we need is the absorption spectrum of the atmosphere, i.e. showing how much of the surface black body radiation is absorbed in the atmosphere per wavelength. All the plots I have seen indicate that damn near 100% of 10 - 20 micron photons are absorbed by a 60 km air column containing 300 ppm of CO2, i.e. the bands are saturated and have been for at least 100 years Now what happens to total absorption if you add stuff to a mixture that is already saturated at that wavelength? Not a lot, IIRC.

Any analysis that tries to predict the the impact of rising CO₂ solely by looking at the radiation spectrum of the earth's surface and how it is or isn't absorbed by the atmosphere, is doomed to failure.   The question isn't how much heat is radiated by the surface through the atmosphere to space, but how much heat is radiated into space by the combined surface and atmosphere.

So, it is indeed true that CO₂ absorption of surface radiation is saturated low in the earth's atmosphere.   The radiation is absorbed, and becomes heat.   That heat is then re-emitted by the atmosphere, but more importantly, it is mixed in the atmosphere by convection.   The atmosphere itself is a giant column of mixed gases, and exhibits a pressure gradient from highest at the surface to essentially zero at the very top of the column.   As a result the CO₂ density in molecules per unit volume also exhibits a gradient from highest at the surface, to zero when you reach space.   It is this density that radiation in the direction of space "sees" to determine what fraction is absorbed.   So that absorption is essentially 100% at the earth's surface, but also declines to zero at the top the atmosphere.   There is therefore an altitude at which on average a photon at a CO₂ absorbed frequency does escape, and below which, on average, it is re-absorbed and returned to the atmospheric heat budget.   The greater the fraction of the atmosphere that is CO₂, the higher that altitude will be.

And this last is the key.   Because in addition to the pressure gradiant, the atmosphere exhibits a temperature gradiant, from warmest at the surface, to very cold at the top of the atmosphere.   Emission of infrared radiation by the gas molecules in the atmosphere is determined by temperature - the lower the temperature, the less emission at the CO₂ wavelengths.   So, as CO₂ concentration goes up, the "net emission altitude" raises, and the actual emission into space of IR radiation at the CO₂ absorption wavelengths decreases.   And, that warms the atmosphere.   A warming atmosphere carries away less heat from the surface, and voila, you've got "global warming."

If this doesn't sound like the "greenhouse effect" as you think you understand it, it's because it's not.   Greenhouse effect is an extremely poor description or analogy of the actual heat dynamics of the combined surface and atmosphere.   It just happens to be one that sticks with non-scientists, so we're collectively stuck with it.

[alancalverd]

We are talking about the very sudden rise that has happened in the last 200 years.

It would be interesting to see the data for the mean surface temperatures of the Pacific Ocean and Antarctica in 1820.

[alancalverd]

We do also risk creating a better world for no good reason

Creating a better world is reason enough. Preventing it getting worse is even more important.

Problems only arise when you strive to do so by sacrificing irrelevant sacred cows (which would have died anyway), nothing happens, and you have no Plan B.

[Petrochemicals]

We do also risk creating a better world for no good reason

I'm sure they thought the same of Thalidomide, cfcs, DDT et Al. Fixation on co2 does risk the possibility of becoming blinkered to impending doom. The CO2 levels are possibly incorrect, co2 could vent from ice due to crushing and fracturing for example. The world is far more resilliant than human culture, a nice slow increace is far more preferable than being dropped like a stone.

Let's face it, Britain is soon to be a popsicle, a bit of extra heat should be helpful.

[Bored chemist]

The CO2 levels are possibly incorrect,

Srsly?

[mikewonders]

So, it is indeed true that CO2 absorption of surface radiation is saturated low in the earth's atmosphere.   The radiation is absorbed, and becomes heat.   That heat is then re-emitted by the atmosphere, but more importantly, it is mixed in the atmosphere by convection.

Welcome to the discussion.  Your description of the gradient dynamics is helpful toward understanding the relative aspects of proximity / pressure / temperature and related radiation zones, thank you.

Given the topic focus being about water vapor increase and it's feedback relationship to warming, can you provide any similar insight on how "additional" water vapor from combustion and atmospheric thermal expansion might play a role in base thermal increase from additional water vapor itself and again the forcing feedback effect / increase that might have on the currently increasing CO2 values?

This topic is a break off of the original question I first posed in seeking to learn if CO2 mitigation alone will have a desired affect to slow warming or if the additional effects of increased water vapor might also be a concern for mitigation strategies, owed to vapor production from combustion processes primarily.

None of the respondents here so far, myself included, have found a proven means of evaluating if a coefficient of effect can be understood sufficiently to estimate, model or build a representative test to help understand it. 

My sense is that assuming water vapor is a static relation in the water cycle changes to the degree with which the current CO2 and warming events are anomalous, relative to prior 300 PPM peaks, now upwards of 420 PPM as new historical highs.

Another way to look at might be to ask if we mitigated all water vapor emissions from combustion tomorrow, would this simply increase surface evaporation on par with reduced relative humidity or moisture density in the atmosphere? Despite water vapor increased impact, can it be changed and reduced as part of CO2 mitigation, assuming temperature rise were effectively limited by CO2 mitigation alone or otherwise.

Thanks again for your input and whatever you might add.