Guest Post by Bill Illis
This post is the first of what will likely be a series on the PaleoClimate.
In this part, we are just going to go through the various estimates for Temperature, CO2 and Sea Levels in the PaleoClimate. This post is also about making the data available to everyone so that others can use it. All of the data presented in this post is available for download at the end in easy to use Excel spreadsheets which also incorporates direct links to the actual data sources used.
PaleoClimate Temperature Estimates Over the Past 570 Million Years
There are various sources we can use for estimates of Temperatures in the PaleoClimate.
We have the ice core dO18 isotope data going back 800,000 years. James Zachos has a high resolution database of dO18 isotopes going back 67.0 million years. Jan Veizer has accumulated an isotope database that goes back 526.5 million years. Dana Royer and Robert Berner applied a ph-correction factor to Veizer’s database and Christopher Scotese has developed Temperature estimates that extend back into the pre-Cambrian.
For the most part, the Temperature estimates are based on dO18 isotopes and these have proven to be reasonably reliable, or more accurately, to be the most reliable temperature estimation method that is available.
The isotope data does require a number of different transformations and smoothing to make it useful as a Temperature proxy. Nobody is really sure what the proper way to carry this out is.
For one, it must be detrended as the data becomes older. The dO18 declines over time due to the radioactivity of the Earth. The above estimates are based on a simple linear detrending formula. The rationale is that the radioactive conditions would have remained reasonably constant over the last 530 million years. Others have used a second order polynomial but this does not result in much difference.
It has been noted that the dO18 isotope data should also be corrected for ice volume, sea level, the concentrations of CaCO3 in the oceans and -ph conditions of the oceans. Royer and Berner applied a ph-correction factor based on Berner’s GeoCarb III CO2 estimates. Again, this doesn’t make much difference except that Royer and Berner’s numbers are now lower than Veizer’s original database would point to.
Effectively, any transformation carried out has still got to match the record that we know about. It is still going to have to show a Carboniferous ice age, an Ordovician ice age, a hot Permian Pangea climate, a hot Cretaceous period, an Antarctic glaciation and the recent ice ages.
In other words, no matter what corrections are applied, one should just end up with something very similar to the above chart.
Detailed Temperature Estimates Over the Past 530 Million Years
Veizer’s database contains over 16,600 individual dO18 isotope data points extending back 526.5 million years. There is sufficient resolution throughout the database that we can be reasonably certain about any specific period.
The above chart has been constructed using Veizer’s data with two different smoothing parameters; a shorter one which preserves more detail and then one that emulates the Phanerozoic Climate Change chart by Robert Rohdes of Global Warming Art. It is likely that both are reasonably accurate and sometimes less smoothing is preferred to more smoothing so that more information can be extracted.
In this case, there really is more information available from the shorter Gaussian smooth. Immediately evident is that certain large temperature changes coincide with some of the large Mass Extinction events in the planet’s history.
The really unusual one is the Permian Extinction event in which 96% of marine species and 70% of large land animals died out in a very short period of time about 251.4 million years ago. Previously this was thought to be due to exceptionally hot conditions or even ocean chemistry changes.
But now one can see that temperatures actually declined by about 5.0C in a very short period of time (something that is that well-known). This temperature drop exactly coincides with the dating of the Siberian Traps volcanic events at 251 to 250 million years ago which is the largest series of volcanic events known in history. An area nearly the size of Australia may have been covered by volcanic magma flows hundreds of metres deep (some places have been measured at 4 kms deep). The volcanoes lasted for about 1 million years and, not surprisingly, temperatures fell.
The other event is the Ordovician extinction event of 443 million years ago in which 50% of the new Cambrian genera of life disappeared. This was always known to be caused by a cooling climate. But now, one can see that there is a very significant drop in the smoothed temperature estimates exactly at 443 million years ago.
The Devonian Extinction seems to be caused by a rapid increase in temperatures, as much as 10.0C in just a few million years.
Notice how the Cretaceous Period, 95 million years ago, is 2.0C to 3.0C higher than the Paleocene Eocene Thermal Maximum. The climate scientists are always talking about how unusual the PETM was but just a few million years earlier, temperatures were quite a bit higher. Dinosaurs even lived in Alaska at the time, and it was a little farther north in the period than it is now. The PETM event does not even look unusual enough in the record to spend much time on.
Notice that the timelines surrounding the Carboniferous Ice Age and the Ordovician-Silurian Ice Age are now clearly defined. These timelines match up very closely with the estimated alignment of the Continents during the periods. Even the short mid-Jurassic Ice Ages are now evident at a point in time when parts of EuroAsia were transiting the North Pole.
Detailed Temperature Estimates Over the Past 67 million Years
Zachos has developed another database of 14,800 individual estimates of dO18 isotopes that covers the past 67 million years with a resolution of less than 100,000 years in most cases.
The time period when Antarctica glaciated over (for the fourth time that is known about) is clearly evident. Temperatures reached as high as 6.0C during the PETM and the periods when Antarctica reglaciated and when Greenland’s glaciers started building occurred at 14 million years ago.
About 2.5 million years, the most recent cycle of ice ages began. In part II of the series, we may take a closer look at the ice ages in more detail.
PaleoCO2 Estimates
There are quite a few different estimates for CO2 in the PaleoClimate. We have the ice cores, we have Mark Pagani 2005 with high resolution estimates between 5.4 million years to 44.5 million years ago and we have Berner’s GeoCarb III estimates which go back to 570 million years ago.
There are others (and they have been included in the CO2 spreadsheet) but they are not as well-accepted as these. The other estimates come mainly from Stomata size (the cells that plants to use to absorb CO2), Paleosols (ancient soil deposits) and Phytoplankton among others.
Using the estimates that are most accepted and given the resolution is higher with the ice cores than with Pagani and then Pagani’s resolution is higher than Berner’s, they have been incorporated back-to-back-to-back as one series as follows.
As most of you are aware, CO2 goes as high as 7,069 ppm 520 million years ago and as low as 180 ppm during the height of the ice ages.
On the same timeline as the PaleoTemperatures Over 67 Million Years chart above, CO2 looks like this over the past 70 million years.
Paleo Sea Level Estimates
Sea level has also been included in the databases since it is not well-known that these high resolution estimates exist. In addition, sea level can certainly have an impact on the climate as well be an indicator for the climate.
There are many different sea level estimates and the most recent one covering the whole period, produced by the world-leading expert on sea level, Bilal Haq, is the most accepted version (Haq, Schutter, 2008).
Sea Level has varied by a large amount throughout history. Sea levels were as much as 265 metres higher than today 100 million years ago and have been as low as 120 metres lower than today during the Last Glacial Maximum.
Sea level seems to vary through three different mechanisms.
- Sea level falls when glaciers build up on land. Obvious enough.
- Sea level falls when continental land masses are concentrated together. Collisions and mountain building tend to squeeze the Earth’s landmasses together and there is less continental shelf area that can affect the average depth of the overall oceans. Related to the last reason, the ocean basins tend to be more mature and deeper in these situations. and,
- Sea level rises when new young ocean basins are opening. New ocean basins generally form at only 2,500 metres depth while mature ocean basins tend to deepen and reach a depth of about 6,000 metres after 100 million years. That means the overall average depth of the ocean is lower when new oceans are forming. This is particularly the case during the Cretaceous when the Atlantic Ocean was just opening up.
Sea levels rose so high during the Cretaceous as the Atlantic was just opening, that the ocean flooded North America from Texas to Inuvik, to Hudson Bay. Europe, the Middle East, North Africa and the central parts of Eurasia were also flooded by shallow oceans.
During the Carboniferous and the Jurassic, the land masses were collected together into the Supercontinent of Pangea. Sea levels fell in the earlier part as glaciers covered large parts of Gondwana, but then they stayed low as the glaciers melted and the continents moved together to form Pangea.
There are periods when there are rapid changes in sea level and these have been used by researchers to date the periods of glaciations. It appears Scotese has used earlier versions of the sea level data to date the glaciations used in his temperature reconstruction.
Conclusion
Putting all the best estimates together, here is a view of the Temperatures, CO2 and Sea Level throughout the past 526 to 570 million years.
In subsequent posts, we may look at the Milankovitch Cycles and the recent ice ages, Continental Drift through time and how that may have affected the climate and then the empirical evidence surrounding the CO2 doubling sensitivity in the PaleoClimate.
The main purpose of this post was to just make the data available to everyone. Others are free to use to use this data in any manner they see fit.
The data is available in three different easy-to-use Excel spreadsheets and can be downloaded at this link. The Paleo Temp Database is a very large file and may be a slow download.
[Paleo Temp CO2 Sea Level Data]
PaleoClimate Temperature, CO2 and Sea Level Estimates
Guest Post by Bill Illis
This post is the first of what will likely be a series on the PaleoClimate.
In this part, we are just going to go through the various estimates for Temperature, CO2 and Sea Levels in the PaleoClimate. This post is also about making the data available to everyone so that others can use it. All of the data presented in this post is available for download at the end in easy to use Excel spreadsheets which also incorporates direct links to the actual data sources used.
PaleoClimate Temperature Estimates Over the Past 570 Million Years
There are various sources we can use for estimates of Temperatures in the PaleoClimate.
We have the ice core dO18 
isotope data going back 800,000 years. James Zachos has a high resolution database of dO18 isotopes going back 67.0 million years. Jan Veizer has accumulated an isotope database that goes back 526.5 million years. Dana Royer and Robert Berner applied a ph-correction factor to Veizer’s database and Christopher Scotese has developed Temperature estimates that extend back into the pre-Cambrian.
For the most part, the Temperature estimates are based on dO18 isotopes and these have proven to be reasonably reliable, or more accurately, to be the most reliable temperature estimation method that is available.
The isotope data does require a number of different transformations and smoothing to make it useful as a Temperature proxy. Nobody is really sure what the proper way to carry this out is.
For one, it must be detrended as the data becomes older. The dO18 declines over time due to the radioactivity of the Earth. The above estimates are based on a simple linear detrending formula. The rationale is that the radioactive conditions would have remained reasonably constant over the last 530 million years. Others have used a second order polynomial but this does not result in much difference.
It has been noted that the dO18 isotope data should also be corrected for ice volume, sea level, the concentrations of CaCO3 in the oceans and -ph conditions of the oceans. Royer and Berner applied a ph-correction factor based on Berner’s GeoCarb III CO2 estimates. Again, this doesn’t make much difference except that Royer and Berner’s numbers are now lower than Veizer’s original database would point to.
Effectively, any transformation carried out has still got to match the record that we know about. It is still going to have to show a Carboniferous ice age, an Ordovician ice age, a hot Permian Pangea climate, a hot Cretaceous period, an Antarctic glaciation and the recent ice ages.
In other words, no matter what corrections are applied, one should just end up with something very similar to the above chart.
Detailed Temperature Estimates Over the Past 530 Million Years
Veizer’s database contains over 16,600 individual dO18 isotope data points extending back 526.5 million years. There is sufficient resolution throughout the database that we can be reasonably certain about any specific period.
The above chart has been constructed using Veizer’s data with two different smoothing parameters; a shorter one which preserves more detail and then one that emulates the Phanerozoic Climate Change chart by Robert Rohdes of Global Warming Art. It is likely that both are reasonably accurate and sometimes less smoothing is preferred to more smoothing so that more information can be extracted.
In this case, there really is more information available from the shorter Gaussian smooth. Immediately evident is that certain large temperature changes coincide with some of the large Mass Extinction events in the planet’s history.
The really unusual one is the Permian Extinction event in which 96% of marine species and 70% of large land animals died out in a very short period of time about 251.4 million years ago. Previously this was thought to be due to exceptionally hot conditions or even ocean chemistry changes.
But now one can see that temperatures actually declined by about 5.0C in a very short period of time (something that is that well-known). This temperature drop exactly coincides with the dating of the Siberian Traps volcanic events at 251 to 250 million years ago which is the largest series of volcanic events known in history. An area nearly the size of Australia may have been covered by volcanic magma flows hundreds of metres deep (some places have been measured at 4 kms deep). The volcanoes lasted for about 1 million years and, not surprisingly, temperatures fell.
The other event is the Ordovician extinction event of 443 million years ago in which 50% of the new Cambrian genera of life disappeared. This was always known to be caused by a cooling climate. But now, one can see that there is a very significant drop in the smoothed temperature estimates exactly at 443 million years ago.
The Devonian Extinction seems to be caused by a rapid increase in temperatures, as much as 10.0C in just a few million years.
Notice how the Cretaceous Period, 95 million years ago, is 2.0C to 3.0C higher than the Paleocene Eocene Thermal Maximum. The climate scientists are always talking about how unusual the PETM was but just a few million years earlier, temperatures were quite a bit higher. Dinosaurs even lived in Alaska at the time, and it was a little farther north in the period than it is now. The PETM event does not even look unusual enough in the record to spend much time on.
Notice that the timelines surrounding the Carboniferous Ice Age and the Ordovician-Silurian Ice Age are now clearly defined. These timelines match up very closely with the estimated alignment of the Continents during the periods. Even the short mid-Jurassic Ice Ages are now evident at a point in time when parts of EuroAsia were transiting the North Pole.
Detailed Temperature Estimates Over the Past 67 million Years
Zachos has developed another database of 14,800 individual estimates of dO18 isotopes that covers the past 67 million years with a resolution of less than 100,000 years in most cases.
The time period when Antarctica glaciated over (for the fourth time that is known about) is clearly evident. Temperatures reached as high as 6.0C during the PETM and the periods when Antarctica reglaciated and when Greenland’s glaciers started building occurred at 14 million years ago.
About 2.5 million years, the most recent cycle of ice ages began. In part II of the series, we may take a closer look at the ice ages in more detail.
PaleoCO2 Estimates
There are quite a few different estimates for CO2 in the PaleoClimate. We have the ice cores, we have Mark Pagani 2005 with high resolution estimates between 5.4 million years to 44.5 million years ago and we have Berner’s GeoCarb III estimates which go back to 570 million years ago.
There are others (and they have been included in the CO2 spreadsheet) but they are not as well-accepted as these. The other estimates come mainly from Stomata size (the cells that plants to use to absorb CO2), Paleosols (ancient soil deposits) and Phytoplankton among others.
Using the estimates that are most accepted and given the resolution is higher with the ice cores than with Pagani and then Pagani’s resolution is higher than Berner’s, they have been incorporated back-to-back-to-back as one series as follows.
As most of you are aware, CO2 goes as high as 7,069 ppm 520 million years ago and as low as 180 ppm during the height of the ice ages.
On the same timeline as the PaleoTemperatures Over 67 Million Years chart above, CO2 looks like this over the past 70 million years.
Paleo Sea Level Estimates
Sea level has also been included in the databases since it is not well-known that these high resolution estimates exist. In addition, sea level can certainly have an impact on the climate as well be an indicator for the climate.
There are many different sea level estimates and the most recent one covering the whole period, produced by the world-leading expert on sea level, Bilal Haq, is the most accepted version (Haq, Schutter, 2008).
Sea Level has varied by a large amount throughout history. Sea levels were as much as 265 metres higher than today 100 million years ago and have been as low as 120 metres lower than today during the Last Glacial Maximum.
Sea level seems to vary through three different mechanisms.
· Sea level falls when glaciers build up on land. Obvious enough.
· Sea level falls when continental land masses are concentrated together. Collisions and mountain building tend to squeeze the Earth’s landmasses together and there is less continental shelf area that can affect the average depth of the overall oceans. Related to the last reason, the ocean basins tend to be more mature and deeper in these situations. and,
· Sea level rises when new young ocean basins are opening. New ocean basins generally form at only 2,500 metres depth while mature ocean basins tend to deepen and reach a depth of about 6,000 metres after 100 million years. That means the overall average depth of the ocean is lower when new oceans are forming. This is particularly the case during the Cretaceous when the Atlantic Ocean was just opening up.
Sea levels rose so high during the Cretaceous as the Atlantic was just opening, that the ocean flooded North America from Texas to Inuvik, to Hudson Bay. Europe, the Middle East, North Africa and the central parts of Eurasia were also flooded by shallow oceans.
During the Carboniferous and the Jurassic, the land masses were collected together into the Supercontinent of Pangea. Sea levels fell in the earlier part as glaciers covered large parts of Gondwana, but then they stayed low as the glaciers melted and the continents moved together to form Pangea.
There are periods when there are rapid changes in sea level and these have been used by researchers to date the periods of glaciations. It appears Scotese has used earlier versions of the sea level data to date the glaciations used in his temperature reconstruction.
Conclusion
Putting all the best estimates together, here is a view of the Temperatures, CO2 and Sea Level throughout the past 526 to 570 million years.
In subsequent posts, we may look at the Milankovitch Cycles and the recent ice ages, Continental Drift through time and how that may have affected the climate and then the empirical evidence surrounding the CO2 doubling sensitivity in the PaleoClimate.
The main purpose of this post was to just make the data available to everyone. Others are free to use to use this data in any manner they see fit.
The data is available in three different easy-to-use Excel spreadsheets and can be downloaded at this link. The Paleo Temp Database is a very large file and may be a slow download.
[Paleo Temp CO2 Sea Level Data]
Paul Dennis (00:08:52) :
Re deeper look at oxygen isotopes, if you are going to form a group I’d like to be in it. There are reasons I can give why some interpretations are suspect. I’ve worked on radioactivity and the properties of materials, but not with oxygen, on which I have merely read. Geoff at sherro1 at optusnet dot com dot au
Dennis Wingo (20:18:30) :
Re military IR research
There are many publications that show CO2 concentrations many times higher than ML. Even on ML itself, the data were cherry-picked when the winds blew from certain directions because the low-lying habitated ground had much higher levels. There’s a European paper I read a year ago that has CO2 at a few thousand ppm above some low altitude land, easy to find with a Net search.
Remember that some “greenhouse” explanations put the greatest interaction effect at just above the ground or sea, just where the high CO2 might lurk. So the concentration at ML is a bit academic when modelling the process.
It’s often stated that CO2 is a well-mixed gas. I therefore infer that the atmosphere hosting the CO2 is well-mixed. Some estimate that there is a travel time of a couple of years from Barrow Alaska to the South Pole. So how does a model explain the global high temperatures of the year 1998 happening inside a year? Did the CO2 at near surface all over the globe suddenly increase a lot in 1998 and then fall back to 1997 levels? Dreamin’.
Bill Illis:
Very nice post; a real contribution to general understanding of paleoclimate. I hope you follow up with an albedo versus climate post soon, since this will be even more relevant to the current and near future climate.
Samoht, evanmjones:
Samoht says: “I agree with you that we must not kill the golden goose. The question is: Who or what is the goose? I think the goose is an environment that is able to sustain life as best as possible with a large species variety etc… Others see the Golden Goose as money, wealth etc… I am septic there.”
You two have combined to clearly define the most vexing and fundamental issue of global warming battles. It is (as Freeman Dyson has noted) in reality a disagreement about morality as much as one about science; a confrontation between “humanists” and “naturalists”.
If we could absolutely know the sensitivity of the Earth’s climate to greenhouse gases, that would not resolve the basic moral question: is it better to maximize human quality of life, or to maximize the quality/species diversity of the natural environment? For example, suppose that 20 years from now climate science really is “settled” in a technical sense, and just about everyone agrees that doubling CO2 would increase average surface temperature buy 1.7+/- 0.15C, and further suppose that the resulting impacts of that temperature increase were pretty well defined in terms of seal level rise, habitat losses, rainfall patterns, and species endangered by the warming. I submit that even with the science essentially “settled”, there would still be a fundamental moral/philosophical disagreement between people about the relative importance of this warming. It will be (and should be!) a question ultimately for the ballot box, not for science.
My observation is that the “humanists” tend to discount scientific data which indicates greater warming, while “naturalists” tend to discount scientific data which indicates lower warming. My sincere concern is that serious work in climate research is tilted (with the best of intentions) heavily toward exaggerated climate sensitivity by a very strong “naturalist” viewpoint held by most researchers in this field. The more extreme the predicted effects of GHG’s the better they seem to like it, since this shifts the political balance. (How many times have we seen “It’s much worse that we thought!” headlines when a paper has been accepted for publication? How many times do we see similar headlines for papers on chemical reaction mechanisms? ) If you tell people New York City may be under water by 2109 (even if it is complete nonsense), then they are more likely to vote to greatly curb CO2 emissions, regardless of the negative economic impact that curb would have.
I do not want the moral/philosophical viewpoint of the climate science community corrupting the science so as to influence what is at bottom a moral, philosophical, and ultimately, a political question. Everyone has the same moral standing as a climate scientist in determining what political course should be taken on GHG emissions, and we all deserve an unbiased scientific evaluation of future warming as part of the input to make that determination. Climate scientists need to recognize this, and keep their thumbs off the balance when global warming is politically weighed.
18, 2009
CO2 driven global warming is not supported by the data
By Girma J Orssengo
http://www.americanthinker.com/2009/10/co2_driven_global_warming_is_n.html
Geoff Sherrington says:
The high temperatures in 1998 were caused by a very strong El Nino (on top of the general ~0.15 C/decade warming trend due to greenhouse gases).
Dennis Wingo says:
There is more variability near the surface because of sources and sinks of CO2. This is especially true in industrialized areas…In fact, I am not sure how much variability there is due to purely natural causes although there probably can be some. However, in the mid-troposphere, the concentration is much more uniform: http://geology.com/nasa/carbon-dioxide-map/ (Note that the entire scale extends over only 10ppm.) The concentration that matters most from the point of view of the greenhouse effect is that away from the surface (in the mid- and upper-troposphere).
gtrip:
Last I checked, they don’t give out Nobel Prizes for repeating discredited “skeptic” talking points. Just as a brief discussion of what is wrong in that article:
(1) Reid doesn’t seem to have an understanding of the radiative physics of the greenhouse effect that was worked out in detail about half a century ago and is agreed upon by pretty much every serious scientist, including skeptical scientists like Richard Lindzen and Roy Spencer.
(2) There is in fact quite a bit of evidence supporting the water vapor feedback. See here for discussion: http://www.sciencemag.org/cgi/content/full/323/5917/1020 Roy Spencer is actually disputing the cloud feedback, which is related to the hydrological cycle…but the cloud and water vapor feedbacks are usually distinguished. I am also not sure where Spencer is with the cloud feedback these days; he had originally suggested that the climate sensitivity for CO2 doubling could be as low as 0.7 C (which implies net negative atmospheric feedbacks) but I noticed in his latest unpublished work now talks about a value of 1.6 to 2.0 C ( http://wattsupwiththat.com/2009/10/04/spencer-on-finding-a-new-climate-sensitivity-marker ), which is moving up toward the IPCC range of 2 to 4.5 C.
(3) There are many ways in which AGW is tested, both the various pieces of the puzzle (such as the water vapor feedback), the climate sensitivity (such as from the response to Mt. Pinatubo eruption and the estimated temperature and forcings at the last glacial maximum as compared to now), and the basic workings of the radiative greenhouse effect (see http://www.skepticalscience.com/saturated-co2-effect.htm for references).
Interesting that the 250 million year temperature peaks are spaced at the proposed time required for us to complete one trip around the galactic center. The increased temperature suggests our travel path is maybe an ellipse?
evanmjones:
I don’t think anyone believes the global temperature change was anywhere close to that. Besides there being polar amplification, I think that these sudden climate shifts are generally thought of having caused warming in some places and cooling in others, quite possibly with very little change in global temperature.
Joel Shore (14:19:44) :
So you seriously propose that adding something like 20 million square kilometers of continental icesheet, replacing most of the (low albedo) forests of the world with (high albedo) steppe, turning all (low albedo) ocean less than 120 meters deep into (high albedo) land, dramatically increasing the area of winter snow and sea-ice, and greatly increase the quantity of atmospheric aerosols only changed the Earths albedo by 0.01?
Well, if you are right, then you can say goodbye to those long-term albedo effects of the current climate change so beloved by warmists, they will be utterly insignificant.
Joel Shore (13:02:17) :
Would you please specify those areas where Younger Dryas is supposed to have resulted in warming and the inception of the Holocene in cooling? Also if the end of Dryas 3 caused “very little change in global temperature” it means that we are still living in a glacial climate since that was the end of the last glaciation and there certainly hasn’t been any major warming since then. Try to talk some sense man.
Joel Shore (12:31:49) :
“(3) There are many ways in which AGW is tested, both the various pieces of the puzzle (such as the water vapor feedback), the climate sensitivity (such as from the response to Mt. Pinatubo eruption and the estimated temperature and forcings at the last glacial maximum as compared to now), and the basic workings of the radiative greenhouse effect (see http://www.skepticalscience.com/saturated-co2-effect.htm for references).”
You really should think before adding a link like that. It has a spectrum that is supposed to show that the Earth’s IR brightness temperature has gone down since 1970 in the absorption bands for CO2 and CH4. However if that spectrum is correct, it also completely kills the water vapor feedback theory since there is absolutely no trace of any strengthening of the H2O absorption band between the CO2 and CH4 bands.
Joel Shore (12:20:35) :
Re the globally hot year 1998.
The question was not whether an El Nino happened. The question was, how did the temperature all over the globe go from a near-decadal average in 1997, to a hot 1998, then back to average in 1999, over sea and land? What mechanism other than an irradiance mechanism can act globally in such a short time, given what we think we know of air circulation velocities?
The problem is to explain the irradiance mechanism. To say it was heat from an El Nino cause is shallow and trite.
This is quite an important question in terms of allowing or disallowing many theories of how energy is redistributed and I hope you give it some serious thought.
The thread is getting close to winding-down now. Thanks for all the comments everyone.
Before we move on in the series, I would like to see what Paul Dennis writes about the isotope data and see if any changes are required.
As I’ve noted, one needs to have a reliable set of temperature and CO2 estimates to go forward properly.
As I’ve also noted, I don’t think any changes/corrections can have a large impact on the temperature estimates.
They should still show:
– a warm Cambrian period 500 million years ago,
– an extensive Ordovician/Silurian ice age 443 million years ago,
– a warm and cool Devonian period 380 million years ago,
– a Carboniferous Ice Age 325 million years ago,
– a hot Permian-Pangea climate 260 million years ago,
– a warm and cool Jurassic period 160 million years ago,
– a hot Cretaceous period 100 million years ago,
– an Eocene Optimum 55 million years ago,
– an Antarctic glaciation 34.5 million years, and,
– the recent ice age cycles starting 2.5 million to 3.0 million years ago.
The next section may just focus on the recent periods including the ice ages and up to about 40 million years ago, when Australia and South America completed their separation from Antarctica.
“Dave Middleton (04:59:51) : The plant stomatal CO2 reconstructions indicate that CO2 levels of 320-390 ppmv have been relatively common during warm periods in the Holocene and recent times. The SI data show that the 20th century increase in atmospheric CO2 was no different than the Roman Warming (300 AD to 400 AD).”
Dave,
Do you have a link on that data? Would love to read it.
I’ve always thought the modern max was artificially low, especially after seeing the GISP2 CO2 data. Though you know it was measured during the holocene (how could they not have sampled that period) they don’t show that data, only the cold periods at ~62kyrs, and 46kyrs or around there, and the data points were already exceeding 300ppm (during the cold periods!). Wonder what it was during the holocene if there were cold spells at 300ppm? Last I read they were on their third study on why the data was no good, but still hadn’t found an answer, or posted the full data. I smell something there…
With 2X the temperature swing in greenland when compared to Vostok, could be wrong, but I would think the CO2 data would not match Vostok very well…
tty:
You can read the original paper to understand how they dealt with the water vapor aspect. The thing about water vapor is that, unlike these other molecules, it is not well-mixed in the atmosphere; in fact, its concentration varies considerably from place-to-place both in the horizontal and vertical directions. So, it would not be as easy to measure the change in outgoing radiation due to it in the way that they did for CO2 and CH4 here.
If you want to look at water vapor in the upper troposphere, I suggest reading this paper: http://www.sciencemag.org/cgi/content/abstract/sci;310/5749/841 or the other papers referred to in this short review: http://www.sciencemag.org/cgi/content/full/323/5917/1020
Samoht, you state:
” But 4 Deg in a century would if it happens constitute a catastrophe ”
Where is your evidence that man is likely to cause this ?
You have not responded to my previous questions:
1. Exactly what “consensus” ? Where is your evidence ?
2. Fossil fuel burning increased about 1200% after 1945. Compare the rate of temperature rise between 1910 to 1940 with subsequent rates of temperature rise (and fall). Exactly where is the increased rate of warming caused by fossil fuel burning supposed to be ?
Dave Middleton (04:09:41) :
“Is there any evidence that the spreading rate was faster in the Cretaceous than it was before or after?”
Yes, lots of evidence for the rates of sea floor spreading. You can just look at the age of the sea floor and the distance from the ridge and you have your rates. Rates of sea floor spreading (and the better thing to consider is area of new seafloor production) were increasing at the start of the Cretaceous and really start to pick up towards the middle of the Cretaceous. We have the opening of the south Atlantic at this time as well as rapid production in the paleo-pacific to replace the the quickly subducting Tethys.
“But I think the high Cretaceous sea level was more a function of the distribution of land mass than rate of sea floor spreading. ”
I am not entirely sure what you are referring too when you mention the “distribution of land mass” and about. I am not sure if you are talking about the arangment of the continents or the current configuation of the various plate margins or what.
If you are refering to tectonics, it is certainly a good thing to consider because tectonic forces can and do cause the “warping” of plates. As plates are colliding, those forces can be translated through the plate and cause large depressions. In fact, that is part of what lead to the formation of the interior Cretaceous seaway on North America. But that just made the interior Cretaceous seaway bigger than it would have been. Sea level was high all over at that time, regardless of the configuration of plate margins. Passive margin or active, almost all continents had shallow interior seas from the middle to late Cretaceous.
Joel Shore (19:38:06) :
“You can read the original paper to understand how they dealt with the water vapor aspect.”
OK, I did, they adjusted it away. Did you notice this sentence:
“Consistently, the difference in the 1,100±1,200 cm-1 window is close
to zero (within +-1 K), while the difference in the 800±1,000 cm-1
region is positive, and lies between about 1 and 2K. It is important
not to over-interpret the observations”
So the result actually suggests higher brightness temperatures in the H2O band and hence less water vapor in the atmosphere in 1997 than in 1970. Furthermore they got their results by taking the difference between two apparently rather noisy datasets obtained by different instruments that could not be calibrated against each other, the classical method of obtaining spurious results.
Dear Anthony,
Could you provide a higher resolution version of the final graph detailing; temperature, CO2 and sea level over time.
Kind regards
IP
Sometimes the links trigger the Spam filter…
Science 18 June 1999:Vol. 284. no. 5422, pp. 1971 – 1973
Wagner et al.
Century-Scale Shifts in Early Holocene Atmospheric CO2 Concentration
American Journal of Botany. 2005;92:690-695
Wagner et al.
Stomatal frequency responses in hardwood-swamp vegetation from Florida during a 60-year continuous CO2 increase
Geology; January 2005; v. 33; no. 1; p. 33-36
Kouwenberg et al.
Atmospheric CO2 fluctuations during the last millennium reconstructed by stomatal frequency analysis of Tsuga heterophylla needles
Quaternary Science Reviews 23 (2004) 1947–1954
Wagner et al.
Reproducibility of Holocene atmospheric CO2 records based on stomatal frequency
Science 22 June 2001:Vol. 292. no. 5525, pp. 2310 – 2313
Royer et al.
Paleobotanical Evidence for Near Present-Day Levels of Atmospheric CO2 During Part of the Tertiary
PNAS October 14, 2008: vol. 105, no. 41, 15817
van Hoof et al.
A role for atmospheric CO2 in preindustrial climate forcing
The most comprehensive paper on SI-derived CO2 reconstructions that I have found is Lenny Kouwenberg’s 2004 PhD thesis, promoted by Visscher and Kurschner…
APPLICATION OF CONIFER NEEDLES IN THE RECONSTRUCTION OF HOLOCENE CO2 LEVELS
A Google search of the authors and titles should return the links. Most of the Science papers are available with a free AAAS subscription, the PNAS paper is free and Kouwenberg’s thesis is freely available. The rest are behind paywalls.
Interested Party (3:59:30)
Here is a higher resolution chart of temperature, sea level and CO2.
http://img11.imageshack.us/img11/1631/paleoco2sealevel.png
Note that the CO2 to temperature comparison should be thought of as per doubling of CO2 given its logarithmic nature. 4,480 ppm is 4 doublings, 2,240 ppm is 3 doublings from 280 ppm.
many thanks bill illis.
I’m currently reading Ian Plimer’s Heaven and Earth… He points out something about CO2 that I had never thought of…
The evolution of multicellular life has actually led to a long-term consumption of the Earth’s reservoir of atmospheric CO2 that had built up over Precambrian and earlier times.
If you performed a linear regression on the Phanerozoic CO2 data series, it would show that atmospheric CO2 is rapidly (geologically speaking) approaching the x-axis (zero).
If mankind wasn’t burning fossil fuels, would the CO2 level bottom out at 280 ppmv for ever? Would it decline to zero? Would it cyclically regenerate like it did in the late Permian to Cretaceous time?
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Joel Shore (14:19:44) :
Bill: Not sure if an estimate has been made for the PETM. For the Last Glacial Maximum, the estimate of the change in forcing due to ice sheet and vegetation changes from Hansen is -3.5 +-1.0 W/m^2 ( http://naturalscience.com/ns/articles/01-16/ns_jeh2.html ), which I guess would correspond roughly to a change in albedo by 0.01, e.g., it would be 0.288 rather than 0.298.
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Joel, many of your responses are reasonable, but this one’s in the 5th dimension.
You’re shooting yourself in the foot w/comments like that. Reminds me of the .01C/century “estimate” of UHI effects for the global surface temp record. Rather sad.
tty says:
A lot of that increased reflectivity is at high latitudes where the sun is generally low on the horizon. The surface albedo of the earth is currently something like 0.09 (with the rest of the albedo of ~0.3 being due to clouds). So, an increase of 0.01 would represent about a 10% increase.
The same climate models that project the future warming have been used to simulate the LGM and have generally gotten coolings in-line with what the available evidence suggests they were.
The change in albedo from the LGM to now was still the largest estimated forcing. All because it was relatively small as a percentage of the total solar radiation received does not make it trivial. And, my impression is that the albedo contribution to the predicted warming globally for the next century is not that great … although it can be fairly large on a local scale.
tty says:
Chapter 6 of the IPCC AR1 WG1 report says of the various abrupt climate changes in general:
The references cited are: Blunier, T., et al., 1998: Asynchrony of Antarctic and Greenland climate change during the last glacial period, Nature, 394, 739–743 (available here: http://www.climate.unibe.ch/~stocker/papers/blunier98nat.pdf ). Landais, A., et al., 2006: The glacial inception as recorded in the NorthGRIP Greenland ice core: timing, structure and associated abrupt temperature changes, Clim. Dyn., 26(2–3), 273–284.
I understand your concern about when we did then warm out of the glacial period and I don’t know the answer to your question. One possibility could be that the Y-D did not represent a return to the glacial period in terms of global temperature…i.e., that global temps remained fairly elevated. Alternatively, it could be that the warming at the end of the Y-D occurred very rapidly in Greenland but much more slowly on a global scale. I don’t know…or even know how much is known about this.