A look at diminishing atmospheric pressure
Guest post by Andi Cockroft
In an unrelated article of mine on Isostacy and Mean Sea Level posted here, I mentioned in passing a thesis paper by Theresa Cole (here) and here: ColeTheresaN2011MSc – which included this graph depicting an observed fall in global annual mean atmospheric pressure since 1916 (from NOAA I believe)
A recent exchange with Theresa, has caused me to revisit this apparent anomaly, and wonder where this is all heading – and indeed how long this has been going on !
But why the heading – So Dinosaurs Could Fly ?
Well, seems that engineers are of the opinion that the pterosaurs were just too heavy to get off the ground given today’s environment, and they must have been helped by far denser air.
Denser air of course means a higher pressure – I have seen estimates ranging from about 3.5 to 8 times that of today. Let’s pick a mid-point of say 5 for the purpose of this post. (I trust these are not the same engineers who state categorically that a Bumble-Bee is incapable of flight)
So from 100Mya to today, how has air pressure gone from a possible 5000 mbar to 1013 mbar of today? And why is it still (possibly) continuing to fall?
Questions that spring to mind are:-
· Is our atmosphere being sucked out in to space?
· Is the composition of the atmosphere changing and so getting lighter?
· Change in water vapour?
· Increasing CO2
· Burning hydrocarbons + O2 -> CO & CO2
· Volcanic eruptions
· Release/Uptake of gases from/to the ocean
· O3 -> O2
· Is an increase in temperature causing a somehow related increase in pressure?
For those who might not remember, I remind readers I do not have strong scientific qualifications in meteorology, hydrology chemistry etc., just an enquiring mind – so feel free to disagree with my arguments here.
In researching this post, I came across many conundrums. Many contradictions or seemingly incongruent theories. But hey, let’s look at what is out there starting with young Earth and work forwards to see what we shall reveal.
I also found myself using those well used weasel words such as could, may, might, suppose etc. Sorry, but given the nature of the discussion – this is just what it is a discussion of some possibilities – not proven fact!
So, just looking at the graph in figure 1 of the past 90 years:- Temperature may have localised effects, but in general, global mean atmospheric pressure at sea level is directly proportional to the mass of the entire atmosphere – the current accepted mean value is around 1013.25 Mbar. So any warming observed over the past 90 or so years should be ruled out as causation – warm or cold the air weighs the same (within reason)
A drop of 1 Mbar may seem trivial over 90 years, but at that rate mother Earth may run out of atmosphere altogether in just 100,000 years !!
Going back 100 million years, for a pressure equivalent to 5000 Mbar, there would have to be either (a) a lot more air, or (b) different composition – or a combination of each.
And of course the raging question – how has a 5000 Mbar atmosphere reduced to todays 1013.25 Mbar?
The Levenspiel et al 2000 paper is well worth a read, and has been cited indirectly here as part of 450 Peer-Reviewed Papers Supporting Skepticism of AGW caused Global Warming here, and referred to at WUWT here.
What was the air pressure for the 97% of Earth’s life before the age of dinosaurs? Levenspiel et alhave three possible alternatives, as shown in Figure 3.
- The pressure could have been at 1 bar throughout Earth’s earlier life, risen to 4–5 bar ~100 Mya (just at the time when the giant fliers needed it), and then returned to 1 bar (curve A).
- The pressure could have been ~4–5 bar from Earth’s beginning, 4600 Mya; and ~65 Mya, it could have begun to come down to today’s 1 bar (curve B).
- The atmosphere could have started at higher pressure and then decreased continuously through Earth’s life to ~4–5 bar ~100 Mya and down to 1 bar today (curve C).
The third alternative seems to be the most reasonable, so let us pursue it. We will also look into the composition of Earth’s atmosphere, but we will first discuss Earth’s surface and see how it affects the atmosphere.
From http://www.engineeringtoolbox.com, the specific gravity of some common gases can be found in the table below:
| Gas | Specific Gravity |
| Acetylene (ethyne) – C2H2 | 0.90 |
| Air1) | 1.000 |
| Alcohol vapour | 1.601 |
| Ammonia – NH3 | 0.59 |
| Argon – Ar | 1.38 |
| Arsine | 2.69 |
| Benzene – C6H6 | 2.6961 |
| Blast Furnace gas | 1.02 |
| Butadiene – C4H6 | 1.87 |
| Butane – C4H10 | 2.0061 |
| 1-Butene (Butylene)- C4H8 | 1.94 |
| Isobutene – C4H8 | 1.94 |
| Carbon dioxide – CO2 | 1.5189 |
| Carbon monoxide – CO | 0.9667 |
| Carbureted Water Gas | 0.63 |
| Chlorine – Cl2 | 2.486 |
| Coke Oven Gas | 0.44 |
| Cyclobutane | 1.938 |
| Cyclopentane | 2.422 |
| Cyclopropane | 1.451 |
| Decane | 4.915 |
| Deutrium – D2 | 0.070 |
| Digestive Gas (Sewage or Biogas) | 0.8 |
| Ethane – C2H6 | 1.0378 |
| Ether vapour | 2.586 |
| Ethyl Chloride – C2H5Cl | 2.23 |
| Ethylene (Ethene) – C2H4 | 0.9683 |
| Fluorine | 1.31 |
| Helium – He | 0.138 |
| Heptanes | 3.459 |
| Hexane | 2.973 |
| Hydrogen | 0.0696 |
| Hydrogen chloride – HCl | 1.268 |
| Hydrogen sulfide – H2S | 1.1763 |
| Hydrofluoric acid | 2.370 |
| Hydrochloric acid | 1.261 |
| Illuminating gas | 0.4 |
| Isobutane | 2.01 |
| Isopentane | 2.48 |
| Krypton | 2.89 |
| Marsh gas | 0.555 |
| Mercury vapour | 6.940 |
| Methane – CH4 | 0.5537 |
| Methyl Chloride | 1.74 |
| Natural Gas (typical) | 0.60 – 0.70 |
| Neon | 0.697 |
| Nitric oxide – NO | 1.037 |
| Nitrogen – N2 (pure) | 0.9669 |
| Nitrogen – N2 (atmospheric) | 0.9723 |
| Nitrous oxide – N2O | 1.530 |
| Nonane | 4.428 |
| Octane | 3.944 |
| Oxygen – O2 | 1.1044 |
| Ozone | 1.660 |
| Pentane | 2.487 |
| Phosgene | 1.39 |
| Propane – C3H8 | 1.5219 |
| Propene (Propylene) – C3H6 | 1.4523 |
| R-11 | 4.742 |
| R-12 | 4.174 |
| R-22 | 2.985 |
| R-114 | 5.9 |
| R-123 | 5.279 |
| R-134a | 3.522 |
| Sasol | 0.42 |
| Silane | 1.11 |
| Sulfur Dioxide – SO2 | 2.264 |
| Toluene-Methylbenzene | 3.1082 |
| Water gas (bituminous) | 0.71 |
| Water vapor | 0.6218 |
| Xenon | 4.53 |
1) NTP – Normal Temperature and Pressure – is defined as air at 20oC (293.15 K, 68oF) and 1 atm ( 101.325 kN/m2, 101.325 kPa, 14.7 psia, 0 psig, 30 in Hg, 760 torr)
Since specific gravity is the ratio between the density (mass per unit volume) of the actual gas and the density of air, specific gravity has no dimension. The density of air at NTP is 1.205 kg/m3
To change the “mass” of the atmosphere to any meaningful way would require say a 75% mercury vapour composition – something not altogether conducive to life as we know it. The alternative is of course just a lot more atmosphere.
Turning our attention for a moment to Earth’s twin, Venus, formed in probably very similar environs, yet Venus retains an atmosphere composed of CO2 and Nitrogen, with a pressure equivalent of around 90 Bar. Venus is closer to the Sun, so receives greater energy, but that cannot in itself account for the very significant differences in today’s environments.
Levenspiel postulates that the creation of Earth’s companion Moon stripped off much of Earth’s mantle, leaving it a rather fluid lithosphere compared to Venus. It is this fluid lithosphere that has allowed continental drift to rearrange and directly affect the planet’s atmosphere. Couple that with a slightly cooler Earth (less sunlight), allowing liquid water to form, and the basis for removal of CO2 is formed.
If say 4 Bya, Earth did have an atmosphere with a 90% CO2 concentration, with a high atmospheric pressure, Levenspiel proposes that simple dissolution in water would see a 50% reduction in nett CO2 atmospheric concentrations.
But it doesn’t stop there
Several cycles take place to remove CO2 from the atmosphere, not least by dissolution in rain, combination with minerals on land and ultimately flowing into the oceans and deposit as sedimentation.
True, some subduction at plate boundaries would recycle carbonates through volcanisms and back into the atmosphere, but over time a gradual reduction of CO2 takes place.
As carbon life-forms take up even more carbonates to build homes for themselves, then die and bequeath these homes to the sea floor as sediment, more and more carbon is tied up as rock.
In Potential Errors in Estimates of Carbonate Rock Accumulating through Geologic Time (pay walled here), Hay calculates that today the continents contain at least 2.82 × 106 km3 of limestone, which are the remains of deposits over the past 570 million years that have not been washed to sea or subducted back into Earth’s interior. This is equivalent to a CO2 atmospheric pressure of 38 bar. If we add the carbonates found on the ocean floor, the equivalent CO2 atmospheric pressure rises to 55 bar.
Adding all this together more than accounts for a 90% CO2 concentration at 90 Bar being reduced over time to a much lower say 20% CO2 and 4 or 5 bar – just right for the pterosaurs to take wing.
Whilst all this was going on, plant life took a turn all of its own.
Evolving from the primordial soup, cyanobacteria initially removed Iron from the oceans and created Oxygen. It was this oxygen that then led to multi-celled life-forms and ultimately diverging between the plants and animals such as protozoa, fish, land animals and dinosaurs
Above: A laminated rock formed by the growth of blue-green algae (i.e., cyanobacteria)
So, if we now accept that 100Mya, there was an atmosphere with about 20% CO2 and say 5 Bar pressure, would plant and animal life have thrived under such conditions? Do we even know that these values were anywhere near accurate?
If we believe the aeronautical engineers, pterosaurs needed a denser air to succeed – that estimate is between 3.5 and 8 times current density (=pressure). So that part of our assumption looks OK on the face of it – yes air would have had to have been more dense.
And what of O2?
Well perhaps it comes down to some type of proxies – yes our old friends !
We do know that there were some pretty impressive flying insects around back then, and it seems well known that insects breath through their “tracheae” – narrow tubes – rather than having lungs or gills. These tracheae transfer O2 directly from the surface of the skin into the organs of the body. The ability to uptake O2 is governed by the length of the tracheae. Big insects naturally have longer tracheae, so uptake less O2 – that is unless O2 is served at higher concentrations and/or pressure so the body can get all the O2 it needs.
Since we know there were huge dragonflies and cockroaches around during the Carboniferous and Permian (300-250Mya), it seems to support a postulation that O2 concentrations were of the order 35% back then, compared to today’s 20%.
Meganeura, a genus of dragonfly from about 300Mya had a wingspan of up to 65cm (2’1”), and Meganeuropsis Permiana from about 250Mya grew even larger – up to 71cm (2’4”).
Neither survived to compete alongside the pterosaurs however. Many believe the concentrations of O2 dropped too low to allow such mega fauna to survive beyond the Permian.
In Part II, I will pick up on your suggestions from comments here, and look to what has happened to reduce Atmospheric Pressure from 5 Bar to 1 Bar, and why it continues to drop today.
Some fundamental physics/thermodynamics for discussion:
The pressure of the atmosphere at the surface of the earth is strictly due to the total weight of the gasses above the point in question. It is basic physics. It does not matter what the temperature of the gas is above the point in question. Also it does not matter what the gas is.
Since PV=nRT, in a constant Volume, the pressure will rise as the increase in absolute temperature. The volume of the gas in the earth’s atmosphere is not constant. Temperature rise will not affect the atmospheric pressure at the surface, again the weight of gas above the earth surface is the determining factor.
The suggestion that burning fossil fuels, due to removing oxygen from the atmosphere as water, decreases the atmospheric pressure is questionable.
The answer would depend on the relative amount of Carbon versus Hydrogen in the fuel that varies considerably. Coal has much less hydrogen than natural gas. Burning carbon will increase the weight of gas at least initially until the CO2 is absorbed somewhere. On the other hand the Hydrogen will burn to water vapor. Someone else needs to clarify what percentage remains in the atmosphere versus how much falls as rain removing oxygen from the atmosphere.
I also have some trouble understanding the theory that the gas surface temperature will rise as the the surface pressure rises, compressing the gas) due to a higher column of gas, more mass of gas. True in a fixed volume the temperature rises as gas is compressed as in an internal combustion engine. However, the process involved for the increase in planet pressure is not adiabatic (no heat loss) for a planet’s atmosphere. Over time the gas will loose the heat to the gases at higher elevations. Possibly someone could explain further.
I’ve always wondered what effect a large, species destroying asteroid would have on Earth’s atmosphere. Would some of it “splash” into space, never to return?
There is a NASA project to obtain the first quantitative measurements of atmospheric pressure on the early Earth, from the Archean Eon >2.5 billion years ago:
It hopes to:
1) improve our understanding of Earths early environment;
2) constrain the development of biogeochemical cycles, notably nitrogen;
3) calibrate greenhouse evolution models by providing data on whether greenhouse forcing gases were major or trace atmospheric constituents;
4) permit testing of hypotheses about Archean oxygen levels; and
5) provide tests for astrobiological models of planetary atmospheres.
Two paleobarometry techniques will be used. The first uses a methodology based on a proven and published paleoaltimetry technique (Sahagian, 1994, 2002) involving the determination of vesicle size distributions from the top and bottom of uninflated basaltic lava flows, then applying the ideal gas law to obtain pressure.
The second marries raindrop formation theory (Lorenz, 1993, 1995) with empirical studies of raindrop impact-crater volume (Ghadiri, 2004). Since atmospheric density controls the final size and velocity of raindrops, fossil raindrop imprints on sedimentary surfaces can be used to extract atmospheric pressure.
The significance of the proposed study applies to NASA Strategic Sub-goal 3C.2 “Understand the processes that determine the history and future of habitability in the solar system, including the origin and evolution of Earths biosphere”
http://astrobiology.nasa.gov/exobiology/projects/archean-paleobarometry-2
It is indirectly related to a Caltech hypothesis described in the paper, “Atmospheric Pressure as a Natural Regulator of the Climate of a Terrestrial Planet with Biosphere,”:
http://media.caltech.edu/press_releases/13266
“As the sun has matured over the past 4.5 billion years, it has become both brighter and hotter, increasing the amount of solar radiation received by Earth, along with surface temperatures. Earth has coped by reducing the amount of carbon dioxide in the atmosphere, thus reducing the warming effect. (Despite current concerns about rising carbon dioxide levels triggering detrimental climate change, the pressure of carbon dioxide in the atmosphere has dropped some 2,000-fold over the past 3.5 billion years; modern, man-made increases in atmospheric carbon dioxide offset a fraction of this overall decrease.)
“The problem, says Joseph L. Kirschvink, the Nico and Marilyn Van Wingen Professor of Geobiology at Caltech and a coauthor of the PNAS paper, is that “we’re nearing the point where there’s not enough carbon dioxide left to regulate temperatures following the same procedures.
“Proof of this hypothesis may come from other research groups that are examining the gas bubbles formed in ancient lavas to determine past atmospheric pressure: the maximum size of a forming bubble is constrained by the amount of atmospheric pressure, with higher pressures producing smaller bubbles, and vice versa.”
I hadn’t thought about it but it would not be surprising to find that the atmosphere has decreased in both density and volume as much of the carbon and oxygen has been preferentially bound up into rocks by biological processes (coal and petrochemicals and limestone etc.) over the last 4 billion years. Our atmosphere is gradually being converted into rocks. Over the past 4 billion years we probably also collected a great deal of space dust, comets, asteroids, etc. gradually adding to the mass of the planet. Higher atmospheric concentrations of both carbon and oxygen would also help explain the larger plants and animals that existed hundreds of millions of years ago.
Interesting to think about these things.
I wait in baited anticipation to see NASA apply this data as an excuse to reduce the rate of sea level rise the way they conversely used GIA to increase it. I suppose I shouldn’t hold my breath…
Robert Morris says: June 2, 2012 at 5:50 am
……………..
Hi Robert
Planet’s polar areas appear to respond to the solar cycles to a degree of intensity which is not possible to explain by the known incoming power measured either by the solar irradiance or the magnetic indices. I came across the Arctic ‘link’ couple of years ago
http://www.vukcevic.talktalk.net/SSN-NAP.htm
and the Antarctic’s more recently
http://www.vukcevic.talktalk.net/SSN-dBzA1.htm
One of constraints of the present day science is that ‘all unknowns are known’, hence if someone comes across something new, unless the accompanying physical mechanism is offered, a label of ‘pseudoscience’ is the best one can hope for. It is our fortune that was not the case in the past centauries when in the fields of electricity and magnetism, great discoveries were made.
Someone mentioned it upthread and it’s something I’ve wondered about too: is the amount of gas compressed into pneumatic tyres, tanks, bottles, footballs and so on of any significance at all in reducing the pressure outside of these items?
Andrew30 says:
June 2, 2012 at 12:48 am
—————————————————-
Andrew30, hold my hand. We’re going to walk into the white building over there. They have cookies and you can draw on paper with different colors.
I believe that water transport to the top of tall trees is attributed to leaf transpiration pulling a very narrow column of liquid from the ground. (As opposed to being pushed up by ambient atmospheric pressure–which would limit lift to approximate 32 feet.) I’m wondering how a much heavier atmosphere might affect this system. Would water transport change because of a change in transpiration? Could an entirely different system of transport evolve not based on capillarity tension? What effect might there be on maximum plant height?
Why do we have to change the atmosphere to satisfy one big bird? Shouldn’t anicent composition, temperature and pressure of the atmosphere satisfy all other species first? Then let the one or two paleontologists argue over the last one remaining. It probably didn’t even fly.
Fascinating, thanks Andy and Anthony.
Oxygen levels higher… CO2 levels a lot higher… atmosphere a lot thicker so more buoyant and warmer… offsets the Faint Sun… makes pterosaurs flight and gigantosaurus long necks that require blood lifting biologically workable maybe… but what about gravity?? Now could the planet have spun faster, thus causing an effectively reduced gravity?
OTOH, biologist Rupert Sheldrake says
How constant are the “fundamental constants”:
…Newton’s Gravitational Constant, Big G, is the one that shows the largest variations. Towards the end of the twentieth century, as methods of measurement became more precise, the disparity in measurements of G by different laboratories increased, rather than decreased. Between 1973 and 2010, the lowest value of G was 6.6659, and the highest 6.743, a 1.1% difference. These published values are given to at least three places of decimals, and sometimes to five, with estimated errors of a few parts per million. Either this appearance of change is illusory, or G really does change. The difference between high and low values is more than forty times greater than the estimated errors (expressed as standard deviations)…
Notice the rapid decline since the 60’s. It’s all those rockets which have punctured the surface tension of the atmosphere and allowed all the air to escape into space.
just a suggestion: what do you think of the gravity theory? this is an interesting article:
http://www.bibliotecapleyades.net/ciencia/ciencia_dinosaurs01.htm
i always thought 1 atm pressure was 1016 millibars….a higher atmospheric pressure in the distant past could explain the dim sun paradox…vast amounts of co2 and o2 that were once in the atmosphere are now in the crust of the earth…as for engineers claiming pterosaurs could not fly…they cant figure out how the dragonflies do their stuff…you learn something new every day
In ancient times, we know that there were giant flying critters. Such could not exist unless the atmosphere was thicker back then. Therefore I at least have known for decades that it was, because that was the only possibility. What I ask is, that being true, why did you not know this?? I have known for years that the ubsurd idea that they flew by using seashore winds was impossible, no such number of flying lizards could survive being so dependent on such limited winds, to say nothing of the insects. What you now need to ask is, what blind spot allowed you to believe the obviously impossible for so long? Is it because someone with an important scientific sounding title did not say it, because it was not in the scientific textbook(even though the obviously absurd seashore theory was)? Do you still have this blind spot? What else might you therefore still be blind to? People who come here supposedly do not ascribe to the idea that it is true just because some person in a white lab coat ( or like Algore say they have one) says so. Perhaps that is not true, perhaps people here are far more susceptible to the argument from authority fallacy than they believe. Perhaps it is time to reexamine why you believe what you believe.
Since I knew that the ancient atmosphere MUST have been thicker back then (it would also help giant non flying critters to breath), I have looked for evidence of how this happened, and found it. A while back, scientists discovered that the protection from atmospheric stripping by the solar wind supposedly afforded by earths magnetic field was less than believed, and it was being stripped. I have also known about the moons tidal effects helping strip the atmosphere for even longer. This is not even counting trapped air bubbles found in antarctic ice, which showed at least two atmospheres of pressure a mere 200,000 years ago or so (also more CO2).
The reason you have just heard about it until now is because scientists have become such specialists that they don’t even know what is going on down the hall. If it isn’t happening in their increasingly narrow specialty, they don’t know about it. besides, they all fight for the same piece of the budgetary pie, and thus only care about the importance, come budget time, of their small department. Other departments are the enemy. I doubt that the dinosaur people will even hear about this (despite the continuing absurdity of their flying reptile theories).
In Germany the concept of the “Fachidiot” is well know. It describes the chap who knows more and more about less and less, to the point where he is incapable of functioning outside his own narrow field. In the English-speaking world, we recognize the expert as the person who avoids the small pitfalls as he sweeps on to the grand fallacy. The generalist, the person who has experience of diverse areas, and the man with insight are necessary counterbalances to Fachidiocy, for it’s not academic background or endless doctorates which are important in revealing scientific truth: the quality of the arguments is more important.
And as for the science, here is the question now, why do we have any atmosphere at all? With the rate it is being stripped, something must have been adding to it for a long time, what was and is that something? How much and of what is being added? Also, how much atmospheric pressure will counteract the early faint sun “paradox” (paradox to people who are “Fachidiots”). Now that you know that the absurd idea that our atmosphere was not always exactly like it is now is false, what other paradoxes does this clear up? What other things do you “know” that are, in fact, completely wrong?
I went through this same reasoning some 30 – 40 yrs ago but I also considered the tuatara, a 100 M-yr old NZ reptile like animal, which operates close to oxygen deficit through it’s lifetime. When it (and dinosaurs et al) evolved the partial pressure of O2 must have been somewhat higher than today.
How much of the atmosphere was blown into space 65 M-yrs ago by the meteor(s) and what effect could that have had on the 02 partial pressure? What effect did a sudden reduction in O2 partial pressure have on dinosaur respiration, i.e. did dinosaurs et al evolve w/ less efficient hemoglobin than mammals/birds of the day?
Over the years I have seen estimates of Earth’s atmospheric pressure (Mars too!!!) of about 250 bar 4 B-yrs ago based on the present known rate of atmospheric loss into space. Note, some of these high oxygen estimates above, ca. 35%, have to be balanced with a large increase in CO2 because RUBISCO, the CO2 fixing molecule in photosynthesis, has an operating envelope of O2/CO2 partial pressures. At 1 bar and 300 ppm CO2 RUBISCO becomes non-productive at 27% O2!
Somebody call Carter Burke, we can easily fix this with a few atmosphere processors. http://www.youtube.com/watch?feature=player_detailpage&v=Yn45pl8yXzk#t=328s
From one non scientist to another: If the atmosphere was considerably denser, the ppCO2 should have been considerably higher, resulting in a significantly different carbonate compensation depth in the oceans, altered pH, and associated differences in aragonite production by marine organisms. Is there significant evidence to support this?
I wonder . . .
a) . . . whether an atmosphere with high concentrations of carbon dioxide and/or oxygen would be as well-mixed as the current atmosphere – either with regard to altitude or spatially?
b) . . . if an oxygen enriched atmosphere (“35% back then”) would be highly combustive? I’ve seen 23% and up given as a mix above which this becomes an issue.
[However, North American Aviation proposed using a 60-40 oxygen/nitrogen mixture for the Apollo command module {NASA wanted and got 100% oxygen} so both the 23% and the 35% may be safer than I’ve thought.]
http://www.wired.com/science/discoveries/news/2009/01/dayintech_0127
Is anyone aware of “lifting body” rather than wings? Look at B-2 bomber as an example. Totally different than commercial passenger planes like Boeing, etc. B-2 comes from Burnelli design…
http://www.aircrash.org/burnelli/cmpcht2b.htm
By the way, this fits well with Nikolov and Zeller’s picture of the ancient past.
For those who are interested, who wondered about N&Z seeming to challenge the Second Law (a reasonable doubt Anthony had, for one) please wander over to Tallblokes Talkshop. I’ve written Part One about my visit to see the experimental work Graeff has been doing, that seems to uphold the necessity for a modification in the Second Law, not in its essentials, but in one detail that has been believed but never, until Graeff, actually tested.
Of course, I believe this work is extremely important. Nullius In Verba and all that.
We’re not talking flying dinosaurs here! We’re talking a disappearing atmosphere that will kill us all, probably by 2100!
There is no question about WUWT’s leadership role in bringing scientific sanity to the public on the issue of global warming (aka, climate change). In my opinion WUWT earned equal leadership status as a prototype for other websites on other issues.
Obviously the IPCC is readying new pseudo-science propaganda weapons for deployment. I not sure what they are calling the thing … maybe something like “sustainability of climatically induced bio-diversity and extinction losses under projected human growth and socio-economic systems” … whatever. The definitions will surely be sharpened and test launched at the upcoming June 22nd Rio Conference. It is being led by our old friend (now a multi-billionaire) Maurice Strong. Now is the time to start a rigorous examination of the Rio agenda and the assumptions of its outcome.
I hope WUWT continue to be willing to play a leading role in this strange journey.
I’m not a scientist. My understanding is that only hydrogen and helium are light enough to reach escape velocity. I would imagine a lot of Helium has been produced by radioactive decay in the last 4.5 billion years, yet the atmosphere is not Helium-rich, it’s just 0.00052% vol of the atmosphere (Wikipedia – which lies).
M Wilson says
(by implication, referring to the given link)
Scientists have speculated that temperatures warm enough to maintain liquid water were the result of a much thicker atmosphere, high concentrations of greenhouse gases or a combination of the two.
Henry says
As I said earlier, I also believe water vapour could have been much higher and temps. could have been much higher.
Whether CO2 is a GHG, is another matter. I do not that as proven beyond reasonable doubt.
http://www.letterdash.com/HenryP/the-greenhouse-effect-and-the-principle-of-re-radiation-11-Aug-2011
Another “average” graph that does not reflect the reality of atmospheric exchanges and climatic evolution…