Not Enough CO2 in Fossil Fuels to Make Oceans Acidic: A Note from Professor Plimer
Posted by admin, October 24th, 2008 - under Opinion.
Tags: Climate & Climate Change, Coral Reefs
In response to a question concerning the likelihood of our oceans becoming acidic from global warming Ian Plimer, University of Adelaide, has replied:
THE oceans have remained alkaline during the Phanerozoic (last 540 million years) except for a very brief and poorly understood time 55 million years ago.
Rainwater (pH 5.6) reacts with the most common minerals on Earth (feldspars) to produce clays, this is an acid consuming reaction, alkali and alkaline earths are leached into the oceans (which is why we have saline oceans), silica is redeposited as cements in sediments, the reaction consumes acid and is accelerated by temperature (see below).
In the oceans, there is a buffering reaction between the sea floor basalts and sea water (see below). Sea water has a local and regional variation in pH (pH 7.8 to 8.3). It should be noted that pH is a log scale and that if we are to create acid oceans, then there is not enough CO2 in fossil fuels to create oceanic acidity because most of the planet’s CO2 is locked up in rocks.
When we run out of rocks on Earth or plate tectonics ceases, then we will have acid oceans.
In the Precambrian, it is these reactions that rapidly responded to huge changes in climate (-40 deg C to +50 deg C), large sea level changes (+ 600m to -640m) and rapid climate shifts over a few thousand years from ’snowball’ or ’slushball’ Earth to very hot conditions (e.g. Neoproterozoic cap carbonates that formed in water at ~50 deg C lie directly on glacial rocks). During these times, there were rapid changes in oceanic pH and CO2 was removed from the oceans as carbonate. It is from this time onwards (750 Ma) that life started to extract huge amounts of CO2 from the oceans, life has expanded and diversified and this process continues (which is why we have low CO2 today.
The history of CO2 and temperature shows that there is no correlation.
Ask your local warmer:
1. Why was CO2 15 times higher than now in the Ordovician-Silurian glaciation?
2. Why were both methane and CO2 higher than now in the Permian glaciation?
3. Why was CO2 5 times higher than now in the Cretaceous-Jurassic glaciation?
The process of removing CO2 from the atmosphere via the oceans has led to carbonate deposition (i.e. CO2 sequestration).
The atmosphere once had at least 25 times the current CO2 content, we are living at a time when CO2 is the lowest it has been for billions of years, we continue to remove CO2 via carbonate sedimentation from the oceans and the oceans continue to be buffered by water-rock reactions (as shown by Walker et al. 1981).
The literature on this subject is large yet the warmers chose to ignore this literature.
These feldspar and silicate buffering reactions are well understood, there is a huge amount of thermodynamic data on these reactions and they just happened to be omitted from argument by the warmers.
When ocean pH changes, the carbon species responds and in more acid oceans CO2 as a dissolved gas becomes more abundant.
Royer, D. L., Berner, R. A. and Park, J. 2007: Climate sensitivity constrained by CO2 concentrations over the past 420 million years. Nature 446: 530-532.
Bice, K. L., Huber, B. T. and Norris, R. D. 2003: Extreme polar warmth during the Cretaceous greenhouse? Paradox of Turonian ∂18O record at Deep Sea Drilling Project Site 511. Palaeoceanography 18:1-11.
Veizer, J., Godderis, Y. and Francois, L. M. 2000: Evidence for decoupling of atmospheric CO2 and global climate during the Phanerozoic eon. Nature 408: 698-701.
Donnadieu, Y., Pierehumbert, R., Jacob, R. and Fluteau, F. 2006: Cretaceous climate decoupled from CO2 evolution. Earth and Planetary Science Letters 248: 426-437.
Hay, W. W., Wold, C. N., Soeding, E. and Floegel, S. 2001: Evolution of sediment fluxes and ocean salinity. In: Geologic modeling and simulation: sedimentary systems (Eds Merriam, D. F. and Davis, J. C.), Kluwer, 163-167.
Knauth, L. P. 2005: Temperature and salinity history of the Precambrian ocean: implications for the course of microbial evolution. Palaeogeography, Palaeoclimatology, Palaeoecology 219: 53-69.
Rogers, J. J. W. 1996: A history of the continents in the past three billion years. Journal of Geology 104: 91-107.
Velbel, M. A. 1993: Temperature dependence of silicate weathering in nature: How strong a negative feedback on long-term accumulation of atmospheric CO2 and global greenhouse warming? Geology 21:1059-1061
Kump, L. R., Brantley, S. L. and Arthur, M. A. 2000: Chemical weathering, atmospheric CO2 and climate. Annual Review of Earth and Planetary Sciences 28: 611-667.
Gaillardet, J., Dupré, B., Louvat, P. and Allègre, C. J. 1999: Global silicate weathering and CO2 consumption rates deduced from the chemistry of large rivers. Chemical Geology 159: 3-30.
Berner, R. A., Lasagna, A. C. and Garrels, R. M. 1983: The carbonate-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million years. American Journal of Science 283: 641-683.
Raymo, M. E. and Ruddiman, W. F. 1992: Tectonic forcing of late Cenozoic climate. Nature 359: 117-122.
Walker, J. C. B., Hays, P. B. and Kasting, J. F. 1981: A negative feedback mechanism for the long term stabilization of the Earth’s surface temperature. Journal of Geophysical Research 86: 9776-9782.
Berner, R. A. 1980: Global CO2 degassing and the carbon cycle: comment on ‘Cretaceous ocean crust at DSDP sites 417 and 418: carbon uptake from weathering vs loss by magmatic activity.” Geochimica et Cosmochimica Acta 54: 2889.
Schwartzman, D. W. and Volk, T. 1989: Biotic enhancement of weathering and the habitability of Earth. Nature 311: 45-47.
Berner, R. A. 1980: Global CO2 degassing and the carbon cycle: comment on ‘Cretaceous ocean crust at DSDP sites 417 and 418: carbon uptake from weathering vs loss by magmatic activity.” Geochimica et Cosmochimica Acta 54: 2889.
CO2 + H2O = H2CO3
H2CO3 = H+ + HCO3-
2Ca2+ + 2HCO3- + KAl2AlSi3O10(OH)2 + 4H2O = 3Al3+ + K+ + 6SiO2 + 12H2O
2KAlSi3O8 + 2H+ + H2O = Al2Si2O5(OH)4 + 2K+ + 4SiO2
2NaAlSi3O8 + 2H+ + H2O = Al2Si2O5(OH)4 + 2K+ + 4SiO2
CaAl2Si2O8 + 2H+ + H2O = Al2Si2O5(OH)4 + Ca2+
KAl2AlSi3O10(OH)2 + 3Si(OH)4 + 10H+ = 3Al3+ + K+ + 6SiO2 + 12H2O
CO2 + CaSiO3 = CaCO3 + SiO2
CO2 + FeSiO3 = FeCO3 + SiO2
CO2 + MgSiO3 = MgCO3 + SiO2
In the oceans, CO2 exists as dissolved gas (1%), HCO3- (93%) and CO32- (8%)
69 Responses to “Not Enough CO2 in Fossil Fuels to Make Oceans Acidic: A Note from Professor Plimer”
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Just filing this here: The National Research Council of the National Academy of Sciences is putting together a panel of 10 to 12 scientists to undertake the 18-month study. The committee will be made up of scientists with expertise in chemical oceanography, paleooceanography, biological oceanography, physiology, marine ecology, resource economics, geochemistry, resource management, and ocean-climate modeling.
http://www.underwatertimes.com/news.php?article_id=29675101038
Because it was?
SJT:
Yes, because it was.
Measurement always trumps belief.
It’s called “EVOLUTION”.
I think this post is pretty pointless.
A better one would be on the acidification of the ocean, that is the gradual lowering of pH. No one is claiming the ocean will become acid (i.e <pH 7).
“The history of CO2 and temperature shows that there is no correlation.”
This is an odd thing to say. Would you expect there to be one? There are so many things that affect temp, why would you expect through geological time for there to be a correlation? Ian Plimer, do you understand the role other gases play, the role continental distributions play, the role the faint early sun hypothesis? If this post is intended as some sort of refutation of the greenhouse effect it is a pretty poor one.
Ok, answers to questions. They could all be answered with the same answer - CO2 has gradually declined with geological time due to it being removed from the atmosphere and deposited at the bottom of the oceans. It’s no big mystery and it certainly has no bearing on whether CO2 is a greenhouse gas. Somehow, though I think Prof Plimer is trying to suggest something else. So I will at least try and entertain with other answers instead.
1) Very few land plants. Land plants didn’t really take off until the Carboniferous, most life was in the sea during the Ordovician and Silurian. There was also much more volcanic activity.
2) Permian Glaciation is a tough one as no one really knows why it happened. I have seen theories though that imply the continental shelves were exposed due to vastly lower sea levels, the oxidation of the material would have resulted in much higher CO2, CH4 and correspondingly lower O2. This has been proposed as a mechanism for the mass extinction.
3. Jurassic-Cretaceous glaciation? Not heard of it. Was it more extensive than the Holocene ice extent? CO2 was probably higher because of volcanic activity… Certainly there was more available in the biosphere, perhaps the reduced usage by plants in colder conditions could have elevated them… Not sure.
Yes, we are living at a time of low CO2, and we are living at a time of low temp. This is following the very long term trend for the Earth of gradual lowering of CO2 and temp. Human’s, however, have never lived with higher CO2 than now.
It’s a bit of a strange post. It doesn’t really have a point except this:
“The history of CO2 and temperature shows that there is no correlation.”
Which is a bit… unimportant.
Here’s something on the Jurassic ‘glaciation’
http://www.ingentaconnect.com/content/geol/pga/2008/00000119/00000001/art00002
This guy reckons the Permian ice house is unrelated to the extinction.
www/network.earthday.net/profiles/blog/show?id=1734264%3ABlogPost%3A24880
He attempts to give clear explanations. Seems the Permian ice age started at the end of the carboniferous.
Maybe the removal of large amounts of CO2 by plant burial (that we now dig up as coal) triggered the ice age?
oops, that link won’t work
http://www.network.earthday.net/profiles/blog/show?id=1734264%3ABlogPost%3A24880
neither will that one…
http://network.earthday.net/profiles/blog/show?id=1734264%3ABlogPost%3A24880
1. Why was CO2 15 times higher than now in the Ordovician-Silurian glaciation?
2. Why were both methane and CO2 higher than now in the Permian glaciation?
3. Why was CO2 5 times higher than now in the Cretaceous-Jurassic glaciation?
The answer to all three, if Plimer didn’t know, is that after the Earth’s first atmosphere of primordial hydrogen and helium was lost due to the Earth’s low gravity, extensive volcanism created the second atmosphere, which was predominantly carbon dioxide. The emergence of life triggered the start of the extremely long term decline in CO2 concentrations, over billions of years. The three points he mentioned were 450 million, 250 million, and 145 million years ago, so CO2 was lower at each stage than the preceding one.
The implicit question is “why wasn’t it hotter then?”. It’s not a complex question to answer: the Sun was less luminous then than it is now. Do the sums and you’ll find that the negative forcing due to the decline in CO2 was handily offset by the positive forcing due to the solar luminosity gradually rising.
I look forward to seeing Ian publish his results in a peer reviewed journal which disprove ocean acidification and which disprove CO2 as a past driver of climate change.
BTW here is what Royer et al. (Ian’s first reference) conclude…
Our estimates are broadly consistent with estimates based on short-term climate records, and indicate that a weak radiative forcing by carbon dioxide is highly unlikely on multi-million-year timescales. We conclude that a climate sensitivity greater than 1.5 °C has probably been a robust feature of the Earth’s climate system over the past 420 million years, regardless of temporal scaling.