From NASA Goddard and the “runaway greenhouse” department:
Venus may have had a shallow liquid-water ocean and habitable surface temperatures for up to 2 billion years of its early history, according to computer modeling of the planet’s ancient climate by scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York.
The findings, published this week in the journal Geophysical Research Letters, were obtained with a model similar to the type used to predict future climate change on Earth.
“Many of the same tools we use to model climate change on Earth can be adapted to study climates on other planets, both past and present,” said Michael Way, a researcher at GISS and the paper’s lead author. “These results show ancient Venus may have been a very different place than it is today.”
Venus today is a hellish world. It has a crushing carbon dioxide atmosphere 90 times as thick as Earth’s. There is almost no water vapor. Temperatures reach 864 degrees Fahrenheit (462 degrees Celsius) at its surface.
Scientists long have theorized that Venus formed out of ingredients similar to Earth’s, but followed a different evolutionary path. Measurements by NASA’s Pioneer mission to Venus in the 1980s first suggested Venus originally may have had an ocean. However, Venus is closer to the sun than Earth and receives far more sunlight. As a result, the planet’s early ocean evaporated, water-vapor molecules were broken apart by ultraviolet radiation, and hydrogen escaped to space. With no water left on the surface, carbon dioxide built up in the atmosphere, leading to a so-called runaway greenhouse effect that created present conditions.
Previous studies have shown that how fast a planet spins on its axis affects whether it has a habitable climate. A day on Venus is 117 Earth days. Until recently, it was assumed that a thick atmosphere like that of modern Venus was required for the planet to have today’s slow rotation rate. However, newer research has shown that a thin atmosphere like that of modern Earth could have produced the same result. That means an ancient Venus with an Earth-like atmosphere could have had the same rotation rate it has today.
Another factor that impacts a planet’s climate is topography. The GISS team postulated ancient Venus had more dry land overall than Earth, especially in the tropics. That limits the amount of water evaporated from the oceans and, as a result, the greenhouse effect by water vapor. This type of surface appears ideal for making a planet habitable; there seems to have been enough water to support abundant life, with sufficient land to reduce the planet’s sensitivity to changes from incoming sunlight.
Way and his GISS colleagues simulated conditions of a hypothetical early Venus with an atmosphere similar to Earth’s, a day as long as Venus’ current day, and a shallow ocean consistent with early data from the Pioneer spacecraft. The researchers added information about Venus’ topography from radar measurements taken by NASA’s Magellan mission in the 1990s, and filled the lowlands with water, leaving the highlands exposed as Venusian continents. The study also factored in an ancient sun that was up to 30 percent dimmer. Even so, ancient Venus still received about 40 percent more sunlight than Earth does today.
“In the GISS model’s simulation, Venus’ slow spin exposes its dayside to the sun for almost two months at a time,” co-author and fellow GISS scientist Anthony Del Genio said. “This warms the surface and produces rain that creates a thick layer of clouds, which acts like an umbrella to shield the surface from much of the solar heating. The result is mean climate temperatures that are actually a few degrees cooler than Earth’s today.”
The research was done as part of NASA’s Planetary Science Astrobiology program through the Nexus for Exoplanet System Science (NExSS) program, which seeks to accelerate the search for life on planets orbiting other stars, or exoplanets, by combining insights from the fields of astrophysics, planetary science, heliophysics, and Earth science. The findings have direct implications for future NASA missions, such as the Transiting Exoplanet Survey Satellite and James Webb Space Telescope, which will try to detect possible habitable planets and characterize their atmospheres.
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Any kind of runaway GHG effect is impossible. Venus is the case of runaway clouds, not run away GHG’s. Besides, the feedback model that supports a run away GHG effect assumes a gain element (i.e. the atmosphere) with an implicit, infinite capacity power supply providing its output power, rather than consuming its input and feedback power to produce the output power. This is an underlying assumption of Bode’s control theory (along with the requirement for strict input/output linearity) both of which climate science conveniently ignores. These are 3 decade old errors that first appeared in Hansen’s 1984 paper on climate system feedback, were obfuscated by Schlesinger’s follow on paper, and have since been canonized by the IPCC.
I suppose we shouldn’t be too hast in our criticism. I mean, they used the same, or similar tools that they use to model the climate here on Earth. And we all know how successful they’ve been with that endeavor.
“There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.” – Mark Twain
Alas, it’s only a matter how many variables are used, so perhaps you don’t even have to fudge the data ! It reminds me of Freeman Dyson’s narrative when he presented Fermi an equation and Fermi citated the great mathematician John von Neumann:” with four variables I can fit an Elephant and with five I can make him wiggle his trunk!”
NASA really has become a joke since all their Germans died or were deported.
When Dan Dare went to Venus, the planet was quite cool otherwise he would not have prevailed against the Mekon and his dastardly Treens.
Hansen’s ocean-boiling model was ridiculous and my thought of running it backwards from a Venusian
starting point was even more so. You were supposed to laugh.
Luckily in real science, nothing is ever settled:
https://www.newscientist.com/article/2100700-mystery-object-in-weird-orbit-beyond-neptune-cannot-be-explained/
So in Venus climate models, clouds act to cool the planet, whereas on Earth, clouds must cause runaway warming. Nice try. Can’t have it both ways, or can you?
Mario Lento
August 12, 2016 at 12:15 pm :
Thankyou Mario for concisely stating the basis of the gravito- thermal effect above, as it follows the gas laws. Trolls like Greg can squirm all they like, but it destroys their case utterly. As demonstrated empirically on Venus and several other bodies. Even stars are formed thus, because 2-3K becomes millions under stellar gas pressure, initiating nuclear ignition.
Simple, and as explained by Maxwell in his Theory of Heat as it applies to atmospheres. “Hockeyschtick Thursday, May 1, 2014
Maxwell established that gravity & atmospheric mass create so-called greenhouse effect
from a comment by climate scientist Pehr Bjornbom at the Stockholm Initiative, a Swedish climate science discussion site that is currently discussing the Hockey Schtick post Why Earth’s climate is self-regulating and independent of CO2, Dr. Bjornbom notes that in 1888 the famous physicist Maxwell wrote that gravity establishes the temperature gradient [adiabatic lapse rate] of the atmosphere, which is independent of radiative forcing from greenhouse gases and dependent only upon gravity and heat capacity of the atmosphere [lapse rate = -gravity/heat capacity]. Thus, an atmosphere comprised of only non-greenhouse gases such as nitrogen & oxygen [over 99% of Earth’s atmosphere] would create a temperature gradient/adiabatic lapse rate/”greenhouse effect” and not be isothermal as claimed by conventional radiative greenhouse proponents.
67 Pehr Björnbom 05.01.2014 at. 00:29
Maxwell discussed convective equilibrium in his book Theory of Heat, 1888, pp. 330-331:”
https://archive.org/stream/theoryheat01maxwgoog#page/n22/mode/1up
“Climate change” on Venus.
http://www.universetoday.com/wp-content/uploads/2013/06/Increasing_wind_speeds_on_Venus-580×500.jpg
CO2 is more likely to cool us by displacing water which can trap heat.
From the article: “A day on Venus is 117 Earth days.”
I think this needs a little more detail:
http://www.universetoday.com/36687/rotation-of-venus/#
“When discussing Venus’ rotation, it is important to note certain distinctions. Rotation is the time it takes for a planet to spin once on its axis. This is different from a planet’s revolution, which is the time it takes for a planet to orbit around another object (i.e. the Sun). So while it takes the Earth one day (24 hours) to rotate once on its axis, it takes one year (365.256 days) to revolve once around the Sun.
Rotational Period:
Unlike most other planets in the Solar System, which rotate on their axes in an counter-clockwise direction, Venus rotates clockwise (called “retrograde” rotation). It also rotates very slowly, taking 243.025 Earth days to complete a single rotation. This is not only the slowest rotation period of any planet, it also means that a single day on Venus lasts longer than a Venusian year.
And, as noted earlier, Venus’ rotation is backwards, relative to Earth and the other bodies in the Solar System. Technically, this means that its rotational period is -243,025 days. It also means that if you could view the Solar System from the position above its celestial north pole, all of the planets (except for Uranus, which rotates on its side!) would appear to be rotating counter-clockwise.
Venus, however, would appear to be rotating in a clockwise direction. Because of this, if you could stand on the surface of Venus, you would witness the Sun rising in the west and setting in the east. But you would be waiting a very long time to see this happen! Read on to find out why…
Sidereal vs. Solar Day:
Another important thing to consider is the difference between a sidereal day and a solar day. A sidereal day corresponds to the amount of time it takes for a planet to rotate once on its axis, which in Venus’ case takes 243.025 Earth days. A solar day, by contrast, refers to the amount of time it takes for the Sun to reappear at the same point in the sky (i.e. between one sunrise/sunset and the next).
A Venusian (aka. Cytherean) Solar Day is the equivalent to 116.75 days on Earth, which means that it takes almost 117 days for the sun to rise, set, and return to the same place in the sky. Doing the math, we then see that a single year on Venus (224.65 Earth days) works out to just 1.92 Venusian (solar) days.”
PA, August 12, 2016 at 10:09 am wrote:
“2. Venus doesn’t have a magnetic field because it is barely rotating. The earths core rotates backwards and the convection currents in the outer core creates the magnetic field.”
The Earth’s core is a fascinating subject:
http://www.livescience.com/39780-magnetic-field-pushes-earth-core.html
Why Earth’s Inner and Outer Cores Rotate in Opposite Directions
The Earth’s magnetic field controls the direction and speed at which Earth’s inner and outer cores spin, even though they move in opposite directions, new research suggests.
Scientists have long suspected that Earth’s magnetic field — which protects life from harmful space radiation — drifts in a slightly westerly direction. That theory was established in the 1690s, when geophysicist Edmund Halley (the same Halley who spotted the eponymous comet) sailed aboard a research vessel through the South Atlantic Ocean and collected enough compass readings to identify this shift.
By the mid-20th century, geologists had gathered further evidence for this drift and had determined that the westerly rotation of the magnetic field exerts a force on the liquid outer core— composed of a molten mix of iron and nickel — that causes it to rotate in a westerly direction. Decades later, geophysicists used deep seismic data to determine that the inner core — a solid iron-nickel alloy that is about the size of the moon — rotates in an easterly direction, at a greater speed than the rotation of the Earth itself.
But, until now, scientists have regarded these rotations within the two layers of the core as separate, with no relation to each other.
Now, researchers at the University of Leeds in England have found a common link between the two rotations by creating a computer model that shows how the rotation of the Earth’s magnetic field can both pull the liquid outer core in a westerly direction while also exerting an opposite force on the inner core that causes an easterly rotation.
“Previously, there have been these two independent observations, and there has not been a link between them,” study co-author Philip Livermore, of the University of Leeds, told LiveScience’s OurAmazingPlanet. “We argue that the magnetic field itself is pushing on the outer core, and there is an equal and opposite push on the inner core.”
And what always causes magnetic fields?
Skepticism of AGW is healthy. So too should be the view on conventional planetary science, the product of the inertia of decades. Question primordial accretion discs, self-generating magnetism, accepted solar system timelines, associated climate (see the Paleo climate record at WUWT, especially prior to about 12k BC) and the process whereby a number of planets somehow actively upwell energy.
NASA is running on the momentum of habit; the product of its socialism for scientists who stay in line.
My NASA culture modelling indicates that they would interpret Venus’s history in this way — where’s my Ph.D.? Also, since nobody understands how Venus’s rotation got the way it is today, it’s pretty rich to start projecting it into the past. A clue is that its siderial rotation is about the same as its year, but going in the other direction.
Their study is pure imagination. They have no evidence as what Venus was like 2 billion years ago, not even any proxy information. The fact remains that even though Venus has an atmosphere that is more than 96% CO2 and is more than 90 times as massive as Earth’s atmosphere, there is no evidence of a radiative greenhouse effect. The high temperatures at the surface of Venus can all be accounted for by the planet’s proximity to the sun and its high surface pressure. Venus’s proximity to the sun may never have allowed it it have enough hydrogen to allow enough H2O to form an ocean.
As soon as I came to the word ‘model’, I quit reading.
“Venus may have had a shallow liquid-water ocean and habitable surface temperatures for up to 2 billion years of its early history….”
…and then CO2 went above 500ppm and runaway greenhouse effect destroyed the planet, just as it will do here. So, stop driving cars, stop using air conditioning, give all your money to your Approved Elected Officials, who will then rule over you from their Rolls Royces and their 30,000 square foot, air conditioned mansions, making sure you use as few resources as possible so they can live lavish lives never before dreamed of by humans. Because they’re important, and you’re not.
Richard,
https://memegenerator.net/instance/59120550
Oopsie! Sounds good to (see image in link).
It may be new to them, but water had been known to exist for awhile on Venus. What Venus doesn’t have that earth does is a magnetic field. Interesting that neither Mars or Venus has much in the way of a magnetic field and both at one time held a lot more water than today.
A repeat in dragging out the tried and tired line about Venus being an example of a runaway green house. I guess the sea level rise and salt stories didn’t quite get the heretics on board. Maybe we could just skip this and copy and paste the arguments from achieves.
The sun started out about 70% as luminous as it is now, and has been warming at a roughly constant rate ever since. In about 1.7 billion years, earth will suffer from a runaway greenhouse, and earth and Venus will become identical twins.
How did they get a 114 day day down to a 60 day day?
The reasoning that the clouds would stop the days warming is weak.
Lack of rotation dooms the planet to a hot hell.
nicholasmjames
August 12, 2016 at 7:24 pm : 90bars and nearly twice the solar input might have helped…..
Remember how much fun you had with SimCity? Now Mattel and NASA bring you SimPlanet.
And another model suggests that a large asteroid impacted and melted Venus crust. You can find a theory for just about any event or cause you can think of. This is just one in a stew pot
It took longer than 2 bn yrs. to evolve multicellular life! (Eutrophic)
I meant eucaryotic.
I don’t get out much… so I just want to double check on this. The same models that can’t hindcast earth’s weather for even a single year, without iterative tweaking that they don’t carry forward, was used to set up on a planet that is nothing like earth then used to hindcast billions of years. And that was published as peer-reviewed science.
Did I get that right or am I missing something?