There's no doubt that when Venus was formed, the planet and it's atmosphere were very hot due to it's compression and increased pressure caused by it's own gravity.
Venus' solar flux is fixed by the distance between the Sun and Venus via the inverse square law.
(I'm assuming variation in Solar emissive power and orbit are insignicant).
Incoming power I = S * πr^2
S is solar irradiance
πr^2 is area exposed to the sun
You describe outgoing radiation E = B x T^4. It's commonly written as:
W = ε σT^4, the Stefan Boltzman equation where:
ε is emissivity
σ is the Stefan Boltzman constant
W Power per square meter.
Total emitted power E = W * 4πr^2
4πr^2 is the surface area of a sphere
Net power:
P = I - E = S * πr^2 - ε σT^4 * 4πr^2
Once Venus was created, 4.5 billion years ago, E > I meaning more energy is emitted than radiated.
The result of this, as energy is lost, is that Venus and it's atmosphere cooled down.
The cooling process would continue until incoming and outging energies balance.
I = E
S * πr^2 = ε σT^4 * 4πr^2
(this is where πr^2 cancels out)
S = ε σT^4 * 4
T^4 = 1/4 * S / ε σ
Take the quartic roots on both sides and you get Venus' effectice temperature of -47C.
There is no way the heat from the creation of Venus 4.5 Billion years ago can explain the difference between the effective (-47C) and actual surface temperature of 464C).
The heat generated at the creation of Venus dissipated Billions of years ago.
So the answer to the question of what causes the excessive temperatures on Venus is not atmospheric pressure.
Apologies, I must have unintentionally double clicked.
I = S pi r^2
From the pespective of theSsun, the area of the Earth exposed to sunlight is a circle with the Earth's radius.
Is E = W * 4πr^2 distributed evenly thoughout the surface of the Earth.
The simple answer is no, W is not consistent across the Earth. The Stefan Boltzman equation is based on Black Body radiation. This assumes that the temperature is the same over the whole surface. It's just an approximation used when calculating the Effective temperature of a planet, the temperature without an atmosphere.
"The obvious cause is the GHG effect." as the exclusive cause of warming is not.
Ignoring water vapour seems worse than ridiculous.
Ignoring PV = nRT seems tantamount to fantasy.
PV = nRT doesn't care which molecules are involved.
AGW demands only CO2 matters.
Mars, Venus and Earth have differences in temperature that align far more closely with the measured pressure for each planet than the CO2 content of each planet's atmosphere.
You: "The obvious cause is the GHG effect."
Where is the empirical evidence?
Saying "the earth is warming" is a circular reasoning. Studies show temperature rises before CO2, not after.
The Ideal Gas Law can be used to model the behaviour of most atmospheres at pressures below 100000 Pa.
However, the behaviour of most gases deviates from that of an Ideal Gas to varying degrees depending on pressure. Also, some gases are further from behaving linke an Ideal Gas than others, eg methane is quite different due to string hydrogen bonds.
""The obvious cause is the GHG effect." as the exclusive cause of warming is not."
In the case of Venus, as far as I know, yes. The difference between the Effective and actual surface temperature is the GHG effect (along with the obvious albedo, cloud reflectivity, aerosols etc. that are all involved).
"Ignoring water vapour seems worse than ridiculous."
Not sure what this is refering to!?
"Ignoring PV = nRT seems tantamount to fantasy."
I haven't ignored PV = nRt and believe it can be used to model most atmospheres.
I haven't used it in calculating an Effective Temperature, but neither did Orwell2024.
"PV = nRT doesn't care which molecules are involved."
This is known as the Ideal Gas Law. Many gases approximate to Ideal Gases at certain pressure/temperature ranges but they aren't Ideal Gases. In general, the higher the pressure, the less like an Ideal Gas real gases become. Ironically, the atmosphere of Venus includes a variety of chemicals that aren't very close to Ideal Gases.
"AGW demands only CO2 matters."
No it doesn't! I really don't know why you would think that.
"Mars, Venus and Earth have differences in temperature that align far more closely with the measured pressure for each planet than the CO2 content of each planet's atmosphere."
Presure (Pa) Temperature (K)
Mars 30 206
Mercury 133 703
Earth 101300 288
Venus 1.38 * 10^11 737
I don't see the relationship, especially when Mercury is included.
The inverse square law and Effective Temperatures are the first approximate calculation people use, not atmospheric pressure.
"You: "The obvious cause is the GHG effect."
Where is the empirical evidence?"
There's quite a lot. Take a look at "Venus Atmospheric Thermal Structure and Radiative Balance" chapter 5 for a good summary.
"Saying "the earth is warming" is a circular reasoning. Studies show temperature rises before CO2, not after."
The world is definately warming up as shown by many temperature reconstructions and satellite measurements.
There's also all of the circumstancial evidence, eg AMOC slowing down, Greenland ice loss etc.
Throughout most of the Earth's history, temperature has led CO2 with a few notable exceptions.
Massive carbon dioxide (CO2) emissions are widely assumed to be the driver of the end-Permian mass extinction (EPME). It has also been proposed that this happened with another two of the five mass extinctions.
The most relevant exception is obviously the current AGW where CO2 is leading temperature change.
There's no doubt that when Venus was formed, the planet and it's atmosphere were very hot due to it's compression and increased pressure caused by it's own gravity.
Venus' solar flux is fixed by the distance between the Sun and Venus via the inverse square law.
(I'm assuming variation in Solar emission power and orbit are insignicant).
Incoming power I = S * πr^2
S is solar irradiance
πr^2 is area exposed to the sun
You describe outgoing radiation E = B x T^4. It's commonly written as:
W = ε σT^4, the Stefan Boltzman equation where:
ε is emissivity
σ is the Stefan Boltzman constant
W Power per square meter.
Total emitted power E = W * 4πr^2
4πr^2 is the surface area of a sphere
Net power:
P = I - E = S * πr^2 - ε σT^4 * 4πr^2
Once Venus was created, 4.5 billion years ago, E > I meaning more energy is emitted than radiated.
The result of this, as energy is lost, is that Venus and it's atmosphere cooled down.
The cooling process would continue until incoming and outging energies balance.
I = E
S * πr^2 = ε σT^4 * 4πr^2
(this is where πr^2 cancels out)
S = ε σT^4 * 4
T^4 = 1/4 * S / ε σ
Take the quartic roots on both sides and you get Venus' effectice temperature of -47C.
There is no way the heat from the creation of Venus 4.5 Billion years ago can explain the difference between the effective (-47C) and actual surface temperature of 464C).
The heat generated at the creation of Venus dissipated Billions of years ago.
So the answer to the question of what causes the excessive temperatures on Venus is not atmospheric pressure.
"The assertion that the temperature on Venus is a consequence of a runaway greenhouse effect is misleading, often tied to a manipulated narrative aligned with certain climate agendas."
"In sharp contrast, carbon dioxide (CO2), present in mere trace amounts at 0.04%, assumes a marginal role."
The effect of CO2 is small when compared to the energy fluxes in Earth's energy budget, the current imbalance being ~1.4 W/m^2. However, that's a large enough imbalance to cause the current rapid rise in Earth's average temperature
This is just to set the pre factor (emissivity) to the same value for all planetary objects. It doesn't really matter for the demo of the exercise: To show that all observed temperatures are determined by distance and pressure in first order : 1/r2 and the pressure. Not surprising.
There's no doubt that when Venus was formed, the planet and it's atmosphere were very hot due to it's compression and increased pressure caused by it's own gravity.
Venus' solar flux is fixed by the distance between the Sun and Venus via the inverse square law.
(I'm assuming variation in Solar emissive power and orbit are insignicant).
Incoming power I = S * πr^2
S is solar irradiance
πr^2 is area exposed to the sun
You describe outgoing radiation E = B x T^4. It's commonly written as:
W = ε σT^4, the Stefan Boltzman equation where:
ε is emissivity
σ is the Stefan Boltzman constant
W Power per square meter.
Total emitted power E = W * 4πr^2
4πr^2 is the surface area of a sphere
Net power:
P = I - E = S * πr^2 - ε σT^4 * 4πr^2
Once Venus was created, 4.5 billion years ago, E > I meaning more energy is emitted than radiated.
The result of this, as energy is lost, is that Venus and it's atmosphere cooled down.
The cooling process would continue until incoming and outging energies balance.
I = E
S * πr^2 = ε σT^4 * 4πr^2
(this is where πr^2 cancels out)
S = ε σT^4 * 4
T^4 = 1/4 * S / ε σ
Take the quartic roots on both sides and you get Venus' effectice temperature of -47C.
There is no way the heat from the creation of Venus 4.5 Billion years ago can explain the difference between the effective (-47C) and actual surface temperature of 464C).
The heat generated at the creation of Venus dissipated Billions of years ago.
So the answer to the question of what causes the excessive temperatures on Venus is not atmospheric pressure.
The obvious cause is the GHG effect.
This comment appears twice - not sure if SS broke or you hit enter twice or something. I'll reply to this one and hope you don't delete it.
Can you explain why the incoming energy,
I = S pi r ^2
is emitted evenly over the entire surface of the sphere via
E = W 4 pi r^2
?
Apologies, I must have unintentionally double clicked.
I = S pi r^2
From the pespective of theSsun, the area of the Earth exposed to sunlight is a circle with the Earth's radius.
Is E = W * 4πr^2 distributed evenly thoughout the surface of the Earth.
The simple answer is no, W is not consistent across the Earth. The Stefan Boltzman equation is based on Black Body radiation. This assumes that the temperature is the same over the whole surface. It's just an approximation used when calculating the Effective temperature of a planet, the temperature without an atmosphere.
PV = nRT is verifiable.
"The obvious cause is the GHG effect." as the exclusive cause of warming is not.
Ignoring water vapour seems worse than ridiculous.
Ignoring PV = nRT seems tantamount to fantasy.
PV = nRT doesn't care which molecules are involved.
AGW demands only CO2 matters.
Mars, Venus and Earth have differences in temperature that align far more closely with the measured pressure for each planet than the CO2 content of each planet's atmosphere.
You: "The obvious cause is the GHG effect."
Where is the empirical evidence?
Saying "the earth is warming" is a circular reasoning. Studies show temperature rises before CO2, not after.
"PV = nRT is verifiable."
Yes.
The Ideal Gas Law can be used to model the behaviour of most atmospheres at pressures below 100000 Pa.
However, the behaviour of most gases deviates from that of an Ideal Gas to varying degrees depending on pressure. Also, some gases are further from behaving linke an Ideal Gas than others, eg methane is quite different due to string hydrogen bonds.
""The obvious cause is the GHG effect." as the exclusive cause of warming is not."
In the case of Venus, as far as I know, yes. The difference between the Effective and actual surface temperature is the GHG effect (along with the obvious albedo, cloud reflectivity, aerosols etc. that are all involved).
"Ignoring water vapour seems worse than ridiculous."
Not sure what this is refering to!?
"Ignoring PV = nRT seems tantamount to fantasy."
I haven't ignored PV = nRt and believe it can be used to model most atmospheres.
I haven't used it in calculating an Effective Temperature, but neither did Orwell2024.
"PV = nRT doesn't care which molecules are involved."
This is known as the Ideal Gas Law. Many gases approximate to Ideal Gases at certain pressure/temperature ranges but they aren't Ideal Gases. In general, the higher the pressure, the less like an Ideal Gas real gases become. Ironically, the atmosphere of Venus includes a variety of chemicals that aren't very close to Ideal Gases.
"AGW demands only CO2 matters."
No it doesn't! I really don't know why you would think that.
"Mars, Venus and Earth have differences in temperature that align far more closely with the measured pressure for each planet than the CO2 content of each planet's atmosphere."
Presure (Pa) Temperature (K)
Mars 30 206
Mercury 133 703
Earth 101300 288
Venus 1.38 * 10^11 737
I don't see the relationship, especially when Mercury is included.
The inverse square law and Effective Temperatures are the first approximate calculation people use, not atmospheric pressure.
"You: "The obvious cause is the GHG effect."
Where is the empirical evidence?"
There's quite a lot. Take a look at "Venus Atmospheric Thermal Structure and Radiative Balance" chapter 5 for a good summary.
"Saying "the earth is warming" is a circular reasoning. Studies show temperature rises before CO2, not after."
The world is definately warming up as shown by many temperature reconstructions and satellite measurements.
There's also all of the circumstancial evidence, eg AMOC slowing down, Greenland ice loss etc.
Throughout most of the Earth's history, temperature has led CO2 with a few notable exceptions.
Massive carbon dioxide (CO2) emissions are widely assumed to be the driver of the end-Permian mass extinction (EPME). It has also been proposed that this happened with another two of the five mass extinctions.
The most relevant exception is obviously the current AGW where CO2 is leading temperature change.
There's no doubt that when Venus was formed, the planet and it's atmosphere were very hot due to it's compression and increased pressure caused by it's own gravity.
Venus' solar flux is fixed by the distance between the Sun and Venus via the inverse square law.
(I'm assuming variation in Solar emission power and orbit are insignicant).
Incoming power I = S * πr^2
S is solar irradiance
πr^2 is area exposed to the sun
You describe outgoing radiation E = B x T^4. It's commonly written as:
W = ε σT^4, the Stefan Boltzman equation where:
ε is emissivity
σ is the Stefan Boltzman constant
W Power per square meter.
Total emitted power E = W * 4πr^2
4πr^2 is the surface area of a sphere
Net power:
P = I - E = S * πr^2 - ε σT^4 * 4πr^2
Once Venus was created, 4.5 billion years ago, E > I meaning more energy is emitted than radiated.
The result of this, as energy is lost, is that Venus and it's atmosphere cooled down.
The cooling process would continue until incoming and outging energies balance.
I = E
S * πr^2 = ε σT^4 * 4πr^2
(this is where πr^2 cancels out)
S = ε σT^4 * 4
T^4 = 1/4 * S / ε σ
Take the quartic roots on both sides and you get Venus' effectice temperature of -47C.
There is no way the heat from the creation of Venus 4.5 Billion years ago can explain the difference between the effective (-47C) and actual surface temperature of 464C).
The heat generated at the creation of Venus dissipated Billions of years ago.
So the answer to the question of what causes the excessive temperatures on Venus is not atmospheric pressure.
The obvious cause is the GHG effect.
Jupitor is the worst possible example to use in this document.
- It's the least understood (nobody is certain what is happening near the core)
- the atmosphere does not approximate to ideal gases due to high pressures
- Jupitor has a significant internal heat source
"Rather, the explanation is more straightforward: temperature elevation correlates with pressure increase."
Yes, temperatures fall with altitude in the troposphere (usually). Temps can rise with reduced pressure as in Earth's stratosphere.
The high Venus surface temperature is not caused by high pressure and you havn't shown that it is.
"The assertion that the temperature on Venus is a consequence of a runaway greenhouse effect is misleading, often tied to a manipulated narrative aligned with certain climate agendas."
You're incorrect opinion
"The earth’s climate is all about water. Oceans, clouds, rain, vapor and their complex interplay."
Clearly not. Apart from the other greenhouse gases, there's albedo, criosphere and the sun!
"In sharp contrast, carbon dioxide (CO2), present in mere trace amounts at 0.04%, assumes a marginal role."
The effect of CO2 is small when compared to the energy fluxes in Earth's energy budget, the current imbalance being ~1.4 W/m^2. However, that's a large enough imbalance to cause the current rapid rise in Earth's average temperature
"Venus' surface temperature stands as an anomaly owing to its exceptionally thick atmosphere (92 bar)"
I think you should clarify the meaning of 'thick'.
If you mean due to the pressure, the statement if incorrect.
If you mean due to the large amount of CO2, it should say so.
A question. Why didn't you use the Stefan=Boltzmann equation including emissivity?
Emissivity varies quite a bit, e.g. Earth ~0.7, Venus ~0.3
"The dominant effect for the high temperature is simply fundamental physics and a well know relation.
P V = N k T"
Not true. High temperatures cannot be sustained by high pressures.
Many gases can be treated as ideal gases. However, at extreme pressures, their behaviour deviated significantly.
"Under such intense pressure, the surface temperature on Venus would likely have soared to thousands of degrees Celsius"
That's only true if high atmospheric pressure causes an increase in a planet's surface temperature, which isn't correct.
Remember, the planets formed around 4.5 billion years ago.
"At 1 bar, the observed temperature is around 30°C, in line with expectations."
Can you go into more detail here. Whatare these expectations based on.
Can you please expound on "To resolve B, we use -18°C for earth (the reported no atmosphere value). "?
Is this saying earth generates heat from within itself that means it reaches a net -18C with no atmosphere but assuming its molten core, etc?
This is just to set the pre factor (emissivity) to the same value for all planetary objects. It doesn't really matter for the demo of the exercise: To show that all observed temperatures are determined by distance and pressure in first order : 1/r2 and the pressure. Not surprising.