Discussion > A temperature timeline for the last 22,000 years
kim, he is not just a fanatic, he is a Green fanatic.
In the event that Trump becomes President, swathes of NASA scientists, their hangers-on, and associated climate science parasites are facing the axe because of Hansen.
As a child, NASA represented everything about the future to me. It is sad to see "the future" regress. That The Guardian is now pushing his dodgy non-peer reviewed dossier, to promote a court case, does seem rather tawdry, but that is a fair reflection of what climate science always was. It has not improved with age, just turned sour and bitter.
According to EM, climate science does not need to "prove" itself. Is Hansen going to test this in court, as a practice dummy run for Mann?
golf charlie
Entropic man: you have accepted falsifiability! That’s a good thing; of course I can accept that proposition, as that is effectively what I have stated at 11:07 PM.
Mr Clarke:
There is no doubt as to the reality of the greenhouse effect…Isn’t there? Then answer me this: why is the temperature of the atmosphere on Venus at altitudes where its pressure is Earth-equivalent not anywhere from 11 to 143°C warmer than its present temperature, which is what Earth’s temperature would be, were it the same distance from the Sun, despite the concentration of CO2 in the atmosphere of Venus being 11+ “doublings” of Earth’s?
… or that manmade activity has increased the burden of greenhouse gases…Has it? You have definitive evidence of this? If you have, please let everyone else know, as they are ALL desperately searching for it.
.. and therefore placed the planet into a radiative imbalance…When hasn’t there been a radiative imbalance? When haven’t temperatures been rising or falling, or the climates changing? We know what the radiative imbalance is now, but what was it 600 years ago, as we sank from the Mediaeval Warm Period into the Little Ice Age? What was it 1400 years ago, as we to the Mediaeval Warm Period?
Radical Rodent
Many palaeoclimate studies have quantified pre-anthropogenic climate change to calculate climate sensitivity (equilibrium temperature change in response to radiative forcing change), but a lack of consistent methodologies produces a wide range of estimates and hinders comparability of results. Here we present a stricter approach, to improve intercomparison of palaeoclimate sensitivity estimates in a manner compatible with equilibrium projections for future climate change. Over the past 65 million years, this reveals a climate sensitivity (in KW−1m2) of 0.3–1.9 or 0.6–1.3 at 95% or 68% probability, respectively. The latter implies a warming of 2.2–4.8K per doubling of atmospheric CO2, which agrees with IPCC estimates.
Making sense of palaeoclimate sensitivity
From Nature magazine, that hotbed of disinformation.
Phil Clarke
On Venus, I have no idea, but would guess it is a consequence of higher albedo, not many sulphuric acid clouds around here. The greenhouse effect has been understood for more than a century, debating its reality is a waste of time.
We know the increase in CO2 is manmade from two lines of evidence: firstly, carbon accounting. Fossil fuels are valuable commodities and we have good records of how much carbon has been extracted and combusted. If all the CO2 emitted was still resident in the atmosphere concentrations would be north of 500ppm, we are fortunate in that the oceans, soils and biosphere have absorbed our excess. Secondly the isotopic signature of CO2 from fossils is different than other sources - Google the Suess Effect.
Phil Clarke
Radical Rodent
I know that you have been given the information your 6.17pm comment requests before. I have supplied it repeatedly down the years.
Each time you reject it because you distrust the source, because it disagrees with your argument or for some private reason of your own.
You then conveniently forget and ask for it again.
Entropic man
What information?
What neither you nor Mr Clarke seem to understand is that so much of your "information" is encapsulated in one phrase: “…I have no idea, but would guess it is a consequence of higher albedo…” (my bold). Nothing wrong with guesses, of course – after all, science is based on guessing, then testing the guess – but you do have to accept that there is a high probability that your guess could be wrong. So, what is wrong with debating the “reality” of a guess? But, for the albedo to force a reduction in temperature of at least 11°C (possibly more than 100°C, if recent claims for ECS are to be believed), when we can only observe it reducing perhaps a few tenths of a degree on this planet is stretching credulity, somewhat.
I suspect, EM, that, were 2023 to come around and we have not had the rise you predict, then you will have some excuse already prepared – after all, you denied that there had been a pause in the warming, despite over 60 peer-reviewed papers trying to explain the pause. You could call it a victory, I suppose, that the scientists and their peers managed to disappear the pause by suitable homogenisation of the data. Ah, well – rue the day when all your dire predictions come to naught, and we face the prospect of another plunge into a slightly deeper Little Ice Age. I do hope that I am wrong; I fear that I might be right. Nature will continue to perform its tricks on us, but will we ever learn that there is little we can do to counter them?
Radical Rodent
Radical Rodent
Then answer me this, why is the temperature of the atmosphere on Venus at altitudes where its pressure is Earth-equivalent not anywhere from 11 to 143°C warmer than its present temperature?
Actually it is.
Let's go through the numbers one more time.
Venus is 30% closer to the Sun and receives 2700W/m2 of insolation. It has an albedo of 0.7.
The amount of energy entering the atmosphere is 0.3*2700 = 695W
For Earth insolation is 1350W/m2. Albedo is 0.3.
The amount of energy entering the atmosphere is 0.7*1350 = 945W
On Venus the atmosphere reaches Earth surface pressure at an altitude of 49.5km. At that altitude the temperature is 66C.
Look at the two graphs here. The earth sea level conditions are marked in grey.
In summary,
Venus takes up 28% less energy from the Sun than Earth.
Venus has a temperature at earth equivalent altitude of 66C, 51C warmer than Earth.
Phil Clarke or I would explain the difference by reference to the higher CO2 content of the Venusian atmosphere. How would you explain the difference?
Entropic man
EM:
"Venus has a temperature at earth equivalent altitude of 66C, 51C warmer than Earth."
A straight question, if I may, please to enlighten me - What is "earth equivalent altitude"?
Thanks.
Mark Hodgson
Mark Hodgeson
Earth equivalent altitude is the height above the surface of Venus at which the pressure is 1013 millibars, the same as the sea level pressure on Earth.
Entropic man
Radical Rodent,
When temperatures start to cool, coal mines can be reopened, safe in the knowledge that burning coal will warm people's homes, but not the climate. The world's biggest and most costly experiment will have proved it.
Climate Scientists will still be arguing amongst themselves, wondering if they can sue each other for redundancy compensation, in a Professional Liability Class Action.
golf charlie
Mark Hodgson
Sorry, spell checker got at your name again.
Entropic man
Yes, you are right, Gwen. It truly saddens me when I read a paper/article which includes phrases such as “Against the backdrop of human-caused climate change…” or “The steady march of global warming…” Or when a once highly-respected organisation can assure us that today is “… the hottest Earth has been “lately”…” – this is after a rise of just 1°C since the Little Ice Age! “Unprecedented”, it now would appear, with global average temperature “…now higher than it has been for most of the last 11,300 years.”
There is a good reason why the Little Ice Age is called the Little Ice Age, and that is because it was a period of unpleasant coldness. This has to imply that it was warmer before the onset of the Little Ice Age. How much warmer? Well, presumably warm enough for the onset of the Little Ice Age to be noticeable, and noticeably detrimental to human development; certainly, progress in Europe slowed, as the growing seasons shortened, or disappeared altogether, and millions starved or froze to death; settlements were abandoned, and many disappeared under glaciers – on other continents, entire forests were subsumed by ice! How do we know this? Because these sites are now reappearing from under the ice – thus, this is evidence that it was at least as hot then as it is now! Until recently, it was long acknowledged that Mediaeval Warm Period was warmer than today, and that the Roman Warm period was warmer than that, and that the Minoan Warm Period yet warmer, and the Holocene Optimum up to about 5°C warmer. But these appear to have been “homogenised” out of history – just what is going on?! Facts, it would appear, have no authority in the Cult of Climate Change; it is all the fault of humans, and humans must be made to suffer (well, except for the high priests of the cult, of course; they may have their sea-side mansions, their all-expenses paid jollies in expensive, exotic locations, etc, etc…).
The madness will end, but how much damage will have been done by then?
Radical Rodent
Radical Rodent: +1
EM:
Thank you for the helpful explanation, and for spotting that darned spell checker.
"Earth equivalent altitude is the height above the surface of Venus at which the pressure is 1013 millibars, the same as the sea level pressure on Earth." I would recognise 1013 millibars as a rough average, given lower low pressure areas and higher anticyclones. However, given variations in pressure, how can we say that 1013 is "the sea level pressure on earth"? Why is temperature at equivalent millibar levels of pressure the appropriate comparison?
Forgive my ignorance. These aren't questions where I'm "having a go" - I'd just like to understand the thinking and the science behind this. As you know, I'm not a scientist. My ancient physics o level is just that - just an o level, and ancient.
Thanks.
Mark Hodgson
Mr Hodgson: it is an attempt to compare the human effects on one planet with a planet with no humans. Okay, a difficult proposition, but worth a go. Climate “scientists” don’t like it as it does not give them the answers they want – the atmosphere of Venus is about 97% CO2 (i.e. 11+ “doublings” of Earth’s concentration); it is also very dense, with a surface pressure way above that on Earth (and a lot, lot hotter), so the only way to make any sort of comparison is to find an altitude where the pressure is Earth-equivalent. This is where the spanner goes in the works – the temperature at that pressure is exactly what the Earth’s temperature would be, were it as close to the Sun as Venus. If the “greenhouse” effect were real, and CO2 was as important a GHG as claimed by the likes of Entropic man, then this temperature should be at least 11°C higher, depending upon which figure for environmental climate sensitivity you accept (they range from about 0.8°C per “doubling” to a more recent claim of up to 13°C per doubling). Naturally, EM, and others, dismiss all this, saying it is because of the higher albedo of Venus – however, the main exponent of this shows that albedo has little, if any, effect upon atmospheric temperatures. As I understand it, there are similar results with Mars (circa 95% CO2), at Mars-equivalent altitudes on Earth.
Now, let us sit back and watch the vitriolic responses to this; it should be interesting. This hypothesis has been set out, with all the sources and calculations given, and, as far as I know, has yet to be verifiably debunked – though it has received an awful lot of invective (examples to follow).
Radical Rodent
Mark Hodgson
Venus is siimilar in size to Earth, but has a very different atmosphere. It is 95% CO2 and much of the rest is sulphuric acid. There is much more gas, so the surface pressure is 90 times greater than Earth.
Surface temperature is 430C.( Remember water boils at 100C) Conventional physics says this is due to the greater greenhouse effect from the extra CO2.
Radical Rodent ressurected an old sky dragon slayer meme.
Those incompetent climate scientists ( /sarc off) say that because Venus has a 95% CO2 atmosphere, the greenhouse effect is stronger and the temperatures should be higher.
The sky dragon slayers, of which RR seems to be a member, believe that there is no greenhouse effect. They claim as evidence that at the altitude at which the air pressure is the same as Earth, the temperature of Venus is the same as Earth.
That turns out not to be the case. Orbiters and landers have measured the temperature and pressure profiles of Venus's atmosphere. At the same pressure altitude, Venus is 51C warmer than Earth.
I don't know whether it is a fair comparison. Radical Rodent presumably thinks it is, so I decided to follow her lead this time.
Personally I wonder. At the 1013mb altitude is a band of sulphuric acid clouds. You would need to ask someone with more expertise what they would do to the temperature profile.
Entropic man
Radical Rodent
Your claimed temperature is 51C lower than the measurements. That alone invalidates your hypothesis since you are starting from a false premise.
Entropic man
Excuse me, Entropic man, but where did I mention any figure for the temperature? I merely stated that the temperature of the atmosphere of Venus at Earth-equivalent pressures is the same as Earth’s would be were Earth the same distance from the Sun as Venus. Obviously, that temperature would be higher than the Earth is, now, as we would be closer to the Sun… derrr…
Radical Rodent
Radical Rodent, the assumption by eartbound Climate Scientists is that Venus never experienced warmer or cooler temperatures.
I am sure that the Venusian Ice Hockey Stick will show a flat shaft, until earthlings started burning coal. Mann may be from Venus after all.
golf charlie
Firstly - evidence in favour of the Greenhouse effect, apart from the observed higher temperatures at the surface than would be expected with no greenhouse, measurements from space of the spectrum of emitted radiation show dips at exactly the wavelengths that are impeded by greenhouse molecules. This must be explained by those claiming no GHE.
Secondly, absent a GHE the temperature / pressure profile of the two planets would be governed only by the Ideal Gas Law and show a constant relationship - like the one claimed for 1 atmosphere pressure - at all pressures, the ratio being the difference in incoming radiation due to differing distances from the Sun. This proves not to be the case, the relationship is not constant, it just happens to be the case at 1 bar, at other pressures the ratio is different, and explained, as my hunch told me, by the differing planetary albedos.
In fact the two profiles are only similar between 50km and 60 km and quite different at other altitudes.OK but what about that bit between 50km and 60km – surely that still needs some explanation. Well distance from the sun is not the only thing affecting received sunlight. Venus is covered with clouds which according to the same source have their tops at an altitude of around 60 km. These clouds give Venus an albedo of 0.6 which means 60%of the sun's energy is reflected back out to space, 40%is absorbed. Earth by comparison has an albedo of 0.3 which means 70% is absorbed. The net difference in energy absorbed between Earth and Venus is thus the inverse ratio of distance to the sun squared time the difference in fraction of energy absorbed.
= (93/67) 2 * 0.4/0.7 = 1.1
Venus only absorbs 10% more solar energy than does Earth yet its temperature at equivalent atmospheric pressure is 66C vs 14C. The difference in black body emission is 749 watts/sqM versus 390 watts/sqM. The close equivalence cited by Mr Huffman would appear to only exist if one ignores the difference in albedo.
The only vitriol appears to be in the Venusian atmosphere ;-)
Phil Clarke
Mind you, you have highlighted a big difference between us, Entropic man – I do not “believe” any theory. I accept theories as presented, but wait further confirmation as to their validity. The “greenhouse effect” is probably a misnomer, anyway, as greenhouses principally work by restricting convection, something that an open atmosphere cannot do. My own hypothesis (which I have never even tried validating further, but which does hold better than “greenhouse effect”, but anyhoo…) is that the principal heating of the atmosphere is by contact with surfaces warmed by solar radiation; this causes the heated air, now less dense, to rise, draw more air over the surface, thus creating winds, as a form of distribution of this heat through the atmosphere. That the thermals so created are strong enough to lift heavier-than-air objects (which vultures famously exploit), and create winds strong enough to drive hundreds of tonnes of many forms of transport and other energy-extraction devices, does indicate the power of such warming. Yes, there will be some absorption of heat by air molecules, but this is not particularly significant, as those that absorb energy will as easily emit that energy when the source is no longer visible. The majority of the atmosphere is composed of gases that neither absorb nor emit the energy to any great extent, so enabling the heat to be retained overnight. This is why, on clear, still nights, surface frost or ice may occur while air temperatures remain well above freezing; also, the visible presence of water at higher altitudes (i.e. clouds) inhibit the radiation of energy to space, hence cloudy nights (winter or summer) tend to be warmer than cloudless nights.
Radical Rodent
Radical Rodent
Let's take your assumption that there is no greenhouse effect at face value. We'll even ignore albedo.
The Stefan-Boltzmann equation says that the temperature of an illuminated surface increases as the 4th√ of the increase in intensity.
The insolation at Venus is twice that of Earth. The 4th √ of 2 is 1.03.
The global average temperature of Earth's surface is 288CK(15C). Venus's equivalent would be 1.03*288 = 297K( 24C)
That is an increase of 9C. That is still 42C short of the difference actually observed, 51C.
In both the literal and metaphorical sense your numbers do not add up.
Entropic man
Let us look at the source, then:
Venus is closer to the Sun, and gets proportionally more power from it. Earth is 93 million miles from the Sun, on average, while Venus is only 67.25 million. Since the intensity of the Sun's radiation decreases with distance from it as 1 over r-squared, Venus receives (93/67.25) squared, or 1.91 times the power per unit area that Earth receives, on average.Since the radiating temperature of an isolated body in space varies as the fourth-root of the power incident upon it, by the Stefan-Boltzmann law, the radiating temperature of Venus should be the fourth-root of 1.91 (or the square-root of 93/67.25) = 1.176 times that of the Earth. Furthermore, since the atmospheric pressure varies as the temperature, the temperature at any given pressure level in the Venusian atmosphere should be 1.176 times the temperature at that same pressure level in the Earth atmosphere, INDEPENDENT OF THE DIFFERENT LEVELS OF INFRARED ABSORPTION in the two atmospheres. In particular, the averaged temperature at 1000 millibars on Earth is about 15ºC = 288K, so the corresponding temperature on Venus, WITHOUT ANY GREENHOUSE EFFECT, should be 1.176 times that, or 339K. But this is just 66ºC, the temperature we actually find there from the temperature and pressure profiles for Venus.
(BTW: here’s an oddity: EM blames his spell-checker for his frequent misspelling of Mr Hodgson’s name, yet it allows him to type “ressurection”, which even my spell-checker insists on correcting.)
Radical Rodent
Radical Rodent
My response to a hypothesis is to run the numbers where possible and see if the hypothesis matches reality.
In this case you do not need to give numbers. All the data is freely available, as is the physics.
As you saw in my earlier posts, your hypothesis predicts temperatures much lower than actually measured. Even given every chance, as I did in my 12.08 comment, there is a 42C mismatch between your hypothesis and reality.
Your hypothesis is wrong.
Entropic man
The extract I posted was a response to that source; as I said the apparent discrepency does not occur at all pressures, as it should, with no GHE and is explicable by the presence at that height of sulphuric acid clouds, which give the two planets very different albedos. Even Jo Nova concurs ...
http://joannenova.com.au/2011/10/there-is-a-greenhouse-effect-on-venus/
And how do you explain the gaps in our planet's emission spectrum if there is no GHE.
And the world's scientists are unaware of convection? Really?
Phil Clarke
I mean 'onset of reglaciation' in the second line @ 5:18 PM.
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