My Oh Miocene

Guest Post by Willis Eschenbach

It was hot here a couple of days ago. I walked past a huge aloe vera plant, taller than my head, that grows by our house. The heat radiating off of the plant was palpable. I could feel a wash of warm air over me as I stood downwind of it. For a while I thought about the curious ability of plants to heat the air around them, and then I let it go.

Figure 1. Solar absorber, natural style. Note how the design efficiently intercepts sunlight because of the spiral, uneven pattern of the leaves. Also note that the design keeps photons from escaping through the funnel-shaped nature of the leaf pattern. Finally, consider that when the plant emits IR from the inner leaves, it will be re-absorbed by outer leaves, perhaps a number of times. This gives the plant, in effect, a local “greenhouse effect” due to the multiple re-absorption of the IR. The leaf geometry also greatly slows down the passage of the air through the plant, once again increasing the local warming. The net of all of those is a warm plant, surrounded by warm air.

I was reminded of our aloe vera again when a friend sent me a copy of the paper “A Warm Miocene Climate at Low Atmospheric CO2 levels,” by Knorr et al. It reports the results of a climate model analysis of the Miocene, the period from about twenty-three million years ago up to five million years ago. It is in press at GRL (paywalled), but the results are discussed here.

In their abstract, we find (emphasis mine):

In this study we present climate simulations of the Late Miocene (11-7 Ma) with a preindustrial CO2 level, using a coupled atmosphere-ocean general circulation model (AOGCM). The simulated global mean surface temperature of ~17.8 ºC represents a significantly warmer climate than today. We have analyzed the relative importance of tectonic [shape and location of the continents] and  vegetation changes as forcing factors. We find that the strongest temperature increase is due to the Late Miocene vegetation distribution, which is more than three times stronger than the impact induced by tectonic alterations. Furthermore, a combination of both forcing factors results in a global temperature increase which is lower than the sum of the individual forcing effects. Energy balance estimates suggest that reduction in the planetary albedo and a positive water vapor feedback in a warmer atmosphere are the dominating mechanisms to explain the temperature increase. Each of these factors contributes about one half to the global temperature rise of ~3 K. Our results suggest that a much warmer climate during the Late Miocene can be reconciled with CO2 concentrations similar to pre-industrial values.

In looking at the effect of plants on the climate, I’d like to discuss the use of the models, how much weight we should put on their results, and how they could be improved.

The first rule of models says

All Models Are Wrong, But Some Models Are Useful

Their usefulness, of course, depends on their ability to replicate the reality which they are modeling. One issue with the models is that many of them still are not what I call “lifelike”. I discussed this problem of “lifelike” climate model results here. If the models do not act like the real climate, why should we believe them? Unfortunately, no one has ever instituted this kind of test to compare all of the models. It should be a part of a standard suite of climate model tests … dream on.

So at the moment we don’t know if the climate model used in this test gives a lifelike simulation of today, much less of ten million years ago. But I digress. The study says (emphasis mine):

We utilize the comprehensive AOGCM ECHAM5-MPIOM without any flux corrections [e.g. Jungclaus et al., 2006]. The atmosphere model ECHAM5 was used at T31 resolution (~3.75º) with 19 vertical levels. The ocean model MPIOM was run at an average resolution of ~3º with 40 vertical layers. Vegetation is a fixed factor represented by specifying different land surface parameters like albedo, roughness length, vegetation ratio, leaf area index and maximum soil water capacity.

Here we run into another modeling problem. They have set up the vegetation parameters to coincide with what we know of the Miocene landscape. This, of course, means that they are using vegetation as a forcing, rather than a feedback.

But we have been informed, over and over, that the vegetation is a feedback and never a forcing …

This is both a strength and a weakness of the models. We can make assumptions like where the vegetation grew and force things in the model to be a certain way. Then we can see what the effect of that on the results might be.

Unfortunately, the climate doesn’t work that way, where one thing holds steady while everything else changes. So even though we can get some insights, we have no assurance that the effect that we find is real. For example, we don’t know if the Miocene vegetation (which is specified) fits with what the model says were the climate patterns of that time.

Setting aside the manifold questions about the model, there were a couple of interesting parts of the study. The first was that they find that the main effect of the plants occurred through a change in the albedo, particularly for the Sahara. This is in accord with my experience of the aloe vera plant, where it was absorbing much more energy than the ground around it. In part this was because of the albedo of the plant being lower than the ground beneath, but in part it was from the geometry of the plant. (This latter effect is neglected in the model.)

The second interesting thing involves these two statements of theirs about the albedo:

The planetary albedo in MIO [the Miocene simulation] is reduced by ~0.014, which causes less shortwave reflection by the atmosphere and a warming.

and

Based on a zero-dimensional energy balance model [e.g. Budyko, 1969] the impact of α [albedo] and ε [effective long wave emissivity] can be quantified, each causing about one half of the global warming of ~3 K.

Assuming the same solar intensity as the present (345 W/m2), which the authors say that they have done, this change in albedo would result in a change in solar radiation of 0.014 times 345 = 4.83 W/m2. Given the temperature change of 1.5°C from the albedo change, this gives a climate sensitivity of:

1.5°C * 3.7 W m-2 per doubling_CO2 / 4.83 W m-2 = 1.15°C per doubling of CO2.

Me, I think that climate sensitivity is an illusion based on a misunderstanding of how climate works … but for those who believe in it, using Knorr et al’s figures and their concepts, that gives a very low sensitivity, well below the IPCC canonical figure. The IPCC AR4 Summary for Policymakers says (emphasis mine):

The equilibrium climate sensitivity is a measure of the climate system response to sustained radiative forcing. It is not a projection but is defined as the global average surface warming following a doubling of carbon dioxide concentrations. It is likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C.

“Very Unlikely”, in IPCC jargon, means less than 10% chance that the sensitivity is less than their minimum estimate of 1.5°C per doubling of CO2. Despite that, this study shows a sensitivity of about three-quarters of the IPCC minimum estimate …

So you’d think that the media headline from this study would be

“Climate Model Finds Extremely Low Climate Sensitivity”

Sadly, that might happen, but only in an alternate universe …

Best to all,

w.

 

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95 thoughts on “My Oh Miocene

  1. The aloe vera plant is an evolved bubble. The canopy is the skin of the northern hemisphere. The trunk is the polar axis while the root system occupies the southern hemisphere. Such is the way that life forms are manifestations of energy forms.

  2. Along with radiative concrete, asphalt, siding and the like, should we now also be recognisant of thermometer placement near plants too? It would seem so. Oh no! The science…unsettling again.

  3. Models are usful tools to assist thinking about a problem; they are qualitive in nature. No weight shold be given to their quantative outputs.

  4. This “multiple re-absorption of IR” is simply scientific nonsense. Like “positive feedbacks” these are nothing whatsoever with physics, but invented pseudoscientific explanations given by the crooked which have great currency with the gullible.

  5. Does Trenbirth’s “Energy Budget” even include the biosphere? Is his “missing heat” wrapped up in all those living things that get energy from the Sun and then store as matter? After all, the oil and coal we combust is just past energy from the Sun stored as matter millions of years ago.

    Just sayin’ …

  6. Ok, I’ll weigh in here since no one else has. First, I’m up ridiculously early which accounts for the first sentence. Second, he needs some more plants around his deck. Third, I’d hate to have to refinish that deck. Fourth, I hope those windows are north facing, though they look reflective.
    Willis, I like your writing. Keep it up.

  7. when you stand downwind of the aloe and feel the warm air -
    do you suppose that air was heated by infrared radiation?
    when i look at the aloe, i see a very efficient shape for a heat sink, such as is used to conduct heat from a cpu to the air.

  8. Willis,

    Thanks for the article! Indeed the Echam climate model is one of the models with the lowest climate sensitivity. They simulated the MWP-LIA-current climate based on the Esper (in other simulations, they used Moberg) reconstruction (with huge natural variability), with reasonable success, while other climate models use Mann’s reconstruction (with very low natural variability). The difference is that with huge natural variability, there is little room for a huge CO2 effect and reverse. See:

    http://coast.gkss.de/staff/storch/pdf/cubasch.oslo_final_060904.pdf

    For the Eemian warm period, they used the same model to simulate two periods at the beginning and the end of the warm interval:

    http://www.mad.zmaw.de/fileadmin/extern/Publications/model_data.pdf

  9. Plants convert Sunlight into matter. Ergo they are a cooling feedback not a warming feedback. Personally I have never felt warmer standing next to a plant of any description, regardless of the weather conditions. Always cooler.

    Forests and wooded areas are always cooler, because the leaves absorb Sunlight and reflect mostly green SW and therefore provide shade below. Then when the wind blows through the trees it is cooled.

    The incoming IR is also used by the plants for energy. The longer the grass on your lawn, the cooler it feels on your bare feet in the hot sun.

    The logic of this piece is upside-down. Why do we always measure temperature in the shade?
    We don’t “say the temperature in the shade, except the shade of a tree, is . . . . .” do we?

    In the hot sun, which is the warmer, bare earth, sand, rock, tarmac and concrete, or grass?

    It is a logical fallacy to claim plants are a warming feedback. Plants cool.

  10. One thing I can agree with is that albedo is most important in long term climate.

    In fact I’m coming to the conclusion that it is the only factor.

    The Sun is the source of all our incoming energy.

    Albedo rejects a varying amount of this energy.

    The remaining energy cannot be increased overall. (or we would have a new energy source)

    All the rest down here is climate.

    Any variation to the energy budget must be external to the Earth, other than albedo.

    As long as there is water, for water vapour, additional GHG’s are irrelevant, as temperatures are reset down each night by radiation.

    Mankind can only influence long term changes in the energy budget via albedo.

    Punching holes in the above summary is welcome as it will increase my knowledge, and possibly some others.

  11. Is it only Miocene plants that cause this warming? If not, when we burn down the village to save the planet by planting trees, are the trees contributing more to “global warming” than the land did before they were planted?

  12. Willis, you had me puzzled this time:
    I live in a rather hot place (north of the Sea of Galilee), with max average temp in summer of 36C.
    My experience is that vegetation (of all kinds) has a cooling factor. It also causes humidity to rise distinctly.
    Where is the truth then?

  13. Well that is a wonderful specimen of an aloe vera plant, Willis. I don’t know how your observations would stand up to scientific inquiry though, not that I am disputing this. However, I can add something. In the New England National Park (NSW) temperate rain forest, there are fire trails driven though it, and this separates the temperate rain forest from adjacent grazing land. Possibly no more than 30 ft maybe 40 ft. But when you step into the rain forest area, the temperature feels warmer and a lot more humid of course. I am not describing a ‘hack your way through Amazon type tropical rain forest, just a temperate and in small areas sub tropical rain forest. The main trees are varied, but there is an abundance of antarctic beeches, that defy becoming deciduous as they would normally but maintain leaves all the year around. They over dominate the eucalypti trees who are forced to grow high to gain foliage, visible to the sun.
    Also these type of rain forests defy bush fires more than other forests, particularly ‘gum’ trees that have oils in their leaves, and also have evolved to survive bush fires.

    It is a very damp area and actually nearer (and at a lower altitude) the coast (and warmer) the problem is leaches. I went to the ladies’ powder room, at the Dorrigo National Park sky walk (I suffer from vertigo so didn’t go on the sky walk, but you can Google and see it if you like) and a Swedish tourist was in there, and removing leaches from her legs. She had only walked 50 meters into the surrounding sub tropical rain forest. Certainly trees and plants give off vapor and also exude energy. But I don’t think this would add to global warming but certainly surrounding
    atmospheric water vapor that would eventually form rain or the likelihood of lower cloud cover.
    Certainly removing large tracts of rain forest in the Amazon area, has with a 10 year scientific report (I studied this at University AT UNE ‘Earth in Crisis? Course. It was only a 100 level course, but I wanted to fill in my BA unit requirements and chose this rather than doing another 300 level course) caused the cloud cover to go higher and actually is thought to alter rain fall not only in the area but up to 100 km away from where the trees were felled. They thought that leaving equal tracts of rainforest per the trees cleared helped solve this problem. Not only for wild life, but also compensated for the amount of transpiration given off from the rainforest when lots of trees are cut down.

    Interesting hypothesis though, go for it.

  14. It has been found that trees have mechanism tries to keep temperatures in an optimum range around 21C.

    Thus if it is hot they are cooler and if it is cold they are warmer, from the link above:
    a recent study using infrared thermal imaging of a mixed forest in Switzerland agreed with the current study: canopy temperature was 4-5 degrees (Celsius) higher than the cool, ambient air temperature of Switzerland.

    Unless this is taken into account the whole thing is an exercise in futility, model or not.

  15. @Will
    > Plants convert Sunlight into matter. Ergo they are a
    > cooling feedback not a warming feedback.

    Yes, I think this is generally true. I first noticed this years ago while scooting around town on a moped, in Florida, The air temperature around groves of trees felt cooler then air around open lots. Vegetation tends to absorb energy, not scatter it. (We get the energy back when we eat the plants or burn them for warmth).

    Aloe vera plants are somewhat unusual in that they they exhibit Crassulacean acid metabolism or “CAM” photosynthesis. So they release CO2 during the day and absorb it at night, opposite of most green plants temperate climates. This allows the plant to conserve its water content (95%) by closing its stomata (pores) during the day when its hottest. This lowers the transpiration of its water content.

    http://en.wikipedia.org/wiki/CAM_photosynthesis

    So, Willis, at what times during the day or night did you notice this thermal phenomena?

  16. The aloe vera plant is most useful for treating small wounds; just cut off a leaf and squeeze some liquid on the damaged skin. Leave it moist, repeat this once again half an hour later. The next morning the wound is closed.
    It might be more useful that the present CAGW climate models!

  17. The Aloe is a CAM plant (there are three types of photosynthesis – CAM, C3 & C4). CAM types includes cacti and other succulents. Their stomata are closed in hot sun (they capture CO2 at night). The aloe plant would be hotter than C3 or C4 plants in the same situation because it is not evapotranspiring (because stomata are closed). Normally (in a C3 tree, say) the evapotranspiration would lead to a cooling effect.

    So to the model – well it would depend on what kind of photosynthesis was dominant in the Miocene. Not significantly different from now, I think.

    By the way, the arrangement of leaves in spirals etc so as not to shade one another is called mosaic.

  18. When short wave radiation is absorbed the energy is converted into usable energy, (in plants energy is used for food/growth) and long wave radiation and unusable energy, heat. Your Aloe Vera plant wasn’t re-absorbing LW radiation it was responding to the initial absorption of SW and producing LW and heat. SW radiation is a constant during daylight hours, it moves at the speed of light, absorption, reflection and re-emission occurs in nanoseconds. Your plant uses what it needs and then expels what it doesn’t want. Re-absorption of LW is extremely unlikely as your plant, by its color and texture, has a predetermined absorption/reflection ratio and absorbing additional LW radiation would probably compromise it. Wondering if your plant is contributing to the temperature, it is, as does everything within the troposphere that can absorb short wave radiation. Yes this does seem like an area for further study. Send me the money. :)

  19. The topics of parastichy, the golden angle, the distribution of sunflower seeds and the pyhllotaxis relationship to Fibonacci numbers and so on – these have been the subject of many papers, some very advanced. It is my personal doubt that the shape and distribution of leaves and the relationship to paths of light and heat do not have much to do with anything energetic. Unless the plant can move to follow the Sun (and yes, some flowers can, but this is largely unrelated) I believe that the energy intercepted by the plant as the sun moves from dawn to dusk is about constant. The geometric shape that you note about Aloe vera seems to arise because plants grow to a template, some being more obvious than others. One beautiful template is shown in

    http://www.fourmilab.ch/images/Romanesco/

    Also, is it possible that the life cycle of a typical plant, including decay, is exothermic?

  20. Plant cells are subject to the evaporative cooling effects of transpiration. This allows them to operate within an acceptable temperature range.
    Perhaps someone will explain the general effect this would have on atmospheric temperature. I can’t, because I am too thick, and never really understood all that stuff about latent heat of evaporation. Like, where does it go?

  21. This article is very consistent with my compilation of the data. The Miocene was up to 4.0C warmer than today, had more precipitation, forests grew over almost the entire planet and CO2 levels were mostly below 280 ppm.

    The difference is the lower Albedo of the Earth’s surface since it was primarily low-Albedo forests in this period and the only high-Albedo ice in the period was in Antarctica which was probably only a third glaciated at this point (sea ice in the winter of course). About 8 million years, the climate became dryer, a few deserts reappeared, and the C4 grasses started growing in greater abundance (prior to this, grasses were rare having only evolved 24 million years ago and they only start to out-compete C3 plants when there are low CO2 levels and when it is dryer).

    What caused the lower Albedo, primarily the location of the continents and the ocean circulation systems. At 25 million years ago, the Antarctic Circumpolar Current was pinched off between Antarctica and South America and the Current stopped. This ended Antarctica’s isolation in an extreme polar climate and caused Antarctica to lose more than half of its ice. The Atlantic Ocean and the Indian Ocean were connected through the Meditteranean-Tethys Sea. The Atlantic and Pacific were connected since the Panama Isthmus hadn’t formed yet.

    The long march to the recent ice ages started at 14 million years ago when Antarca started reglaciating and the Current started up again, at 8 million years ago when the climate became dryer and the Meditteranean closed off and at 3 million years ago when ice started building in the northern hemisphere as Greenland drifted far enough north to accumulate continental sized glaciers.

    Albedo as an explanation rather than CO2 (these are my estimates, there isn’t really any peer-reviewed ones). Albedo only needs to change by a very small amount to have large impact on temperatures but it also takes a lot of change in the Earth’s surface to move the numbers off 30%, primarily glacial ice build-up.

  22. In the right places, on a sunny windy day you can feel the heat boiling off dark green pines. It takes some distance for the hot air off the pines to mix with the cooler air and you can definitely feel the temperature changes (probably 10 F at times). Since many pine forests were clear cut at the turn of the century, I always thought temperature graphs starting around 1900 in such areas were “logging-biased” in a double-whammy fashion because 1) the intial 1900 temperatures were biased colder (because of bare clearcut ground), and 2) the eventual regrowth of pine would make the area experience a local warming that had nothing to do with anything other than the regrowth of dark pines.

  23. Healthy Aloe Vera leaves are green. This plant looks very unhealthy. You may have been noting the heat of decay from all its dead and dying leaves.

  24. One thinks of Gaia:

    Watson, A. J., and Lovelock, J. E. 1983. “Biological Homeostasis of the Global Environment: the Parable of Daisy World,” Tellus, vol. 35B, no. 4, pp. 284-289.

  25. I think models do have a couple of good uses. One is to teach students about the major factors in a system and how they inter relate and interact, The second is to demolish manifestly ridiculous claims made by the uninitiated (where words just wont do the job).
    But anyone who uses them to predict is an idiot imo.

  26. As usual “It is more complicated than you thought”

    So plants will try to alter the environment to cooler or warmer to give themselves the optimum temperature. There is also the “shade is cooler” wet feels warmer in hot weather and cooler in cold weather and the change in the amount of wind under a forest canopy.

    Have you checked the temperature next to the Aloe Vera and a short distance away with wet and dry bulb thermometers at different times of day and at different ambient temperatures, Willis? It would be an interesting study.

  27. Julian Braggins – I think fundamentally you are correct. The energy the Earth receives is dictated by the relevant energy output of the Sun and the distance the Earth is from it. How much temperature in the atmosphere is dictated by air pressure and not the composition of the atmosphere as shown here. Everything else is the interaction of energy and the chaotic fluid systems (gaseous and liquid) of the planet and is best described as weather. It is a matter of debate or definition as to wether or not the albedo is really part of the interaction (weather) or part of the energy profile (climate). For me albedo at the top of the atmosphere affects the base energy and is climate whereas albedo at any other point is part of the interaction and is therefore weather.

  28. Just like to make the point that the plant in the picture is not Aloe Vera. It is an Aloe, Aloe Vera is a different plant http://4.bp.blogspot.com/_pUjFBZdt6fI/TK6OZ8tD-mI/AAAAAAAAABQ/Wf7gTHAk_CY/s1600/Aloe-Vera-Plant.jpg which is more like a single head. The above plant is an Aloe, but I’m not sure exactly which one it is. eg http://en.wikipedia.org/wiki/List_of_Aloe_species there are many species of Aloe, and the pictured one is not Aloe Vera….

  29. Plants DO modify their own micro-climate towards THEIR ideal. In so doing, collectively they modify the macro-climate. When plants inhabit the entire globe, we will have achieved the ideal climate, in respect to food production and temperatures. It would also mean the current ice age has come to a end… finally. A new equilibrium era will have begun, and reshaping familiar coastlines will follow, this homogenization, NATURALLY. How we maintain sufficient CO2 levels to sustain such levels of bio-mass, is another matter.

    Hominidae are an important part of this bio-mass. Being a predatory species, we will thrive when our prey thrives. Familiar geographic features are unimportant to this march, and life continues to reorganize. As, since time immemorial, we must still follow the caribou/buffalo herd. GK

  30. the Echam climate model is one of the models with the lowest climate sensitivity

    But it seems well within the IPCC range

    The climate sensitivity of ECHAM4 is about 2.6ºC. which is different to what Willis is saying

  31. Taking results at face value, the obvious question is how much of global temp change over the last 100 years is due to land use / vegetation changes over the same time period, as this study suggests the effect could be considerable & we know our global landscape has been modified significantly over the same time period. I recall that Pilke Sr has published on this concept.

  32. The dispute over warming versus cooling of plants reminded me of this paper by John Christy.

    http://journals.ametsoc.org/doi/abs/10.1175/JCLI3627.1

    In the Christy paper, the main effect on temperature was due to IRRIGATION of the California central valley rather than directly due to plants, but I think the main argument holds forplants versus no plants regardless of irrigated or growing naturally. Plants have a lower albedo than the naked ground. This will result in more energy absorbed by the earth and less reflected away. Plants also transpire . The result will be cooler days and somewhat warmer nights, with an overall net warming..

  33. Interesting. Most pines’ use the end-needles on the branch-tips to reflect & focus light on the central terminal bud. I’ve visually noted this on sunny days as the tip-buds light up like candles.

  34. The models are doing what they are being used to do show CO2 and temperature going up to provide a purpose for taxes, regulations and red tape to counter the whole thing.

  35. Fascinating article.

    Willis, you appear to have made an error in comparing climate sensitivities. The IPCC ranges include water vapor feedback, whereas your 1.15 C estimate is based only on albedo change. Apples and oranges, no? Further: Knorr et al attributed half of the 3K Miocene warming to the water feedback (also clear from the abstract).

  36. My house: Surrounded by 27 major trees. Mostly Red and White OAKS.

    Front thermometer, back thermoment (remotes)…and walk out in the street and look at the “official” temperature.

    Typically 4 to 8 degrees F LOWER in the summer, (closer to 8 during the “peak of the day”.)

    Then 2 to 4 degrees HIGHER during the winter (than the “offical” temps.)

    Yes, a little “micro universe” with different conditions than the “macro” world. Cause? Agreeded, during the summer- net absorbtion of incoming SWR. During the winter, “insulation”, damping of outgoing LWR.

    Net balance? NO IDEA!

    Max

  37. They say half is the albedo change and half is the water vapor feedback. This means that the sensitivity including feedback is 2.3 degrees per doubling, not 1.15. I don’t know what Willis is talking about.

  38. Truthseeker says:
    October 1, 2011 at 6:24 am


    Everything else is the interaction of energy and the chaotic fluid systems (gaseous and liquid) of the planet and is best described as weather.

    What you say is true (“best described as weather”), but that’s only part of the picture. The liquid portion of the fluid systems you identify, the ocean, is most significant in absorbing energy from the sun, is the source of the vast majority of the water found in the atmosphere, and also a substantial reservoir and source of heat. Yet most people don’t think of it having much impact on weather–perhaps weather is just the most obvious manifestation of the vast oceans–especially for those of us that live far inland.

  39. Hi Willis,

    if you did a careful analysis of my tables

    http://www.letterdash.com/HenryP/henrys-pool-table-on-global-warming

    -suggest you make hard copies -
    you can make a no. of interesting observations

    1) modern warming appears to be driven by an increase in maxima, not minima. It is the increase in maxima that happen during the day that drives up the average temp. and also that of the minima.
    If it were minima (that happen during the night) pushing up the average temp.s we should agree that an increase in GHG’s was the cause of it. As it stands at the moment we have to conclude that the warming of our planet was largely natural.
    2) Maxima increased both in the SH and the NH but if you look at average temps. (= Means) it appears that the global warming is not really global. It would seem that in the NH, which has most of the landmasses, some of the additional heat (most probably caused by more sunshine and/or less clouds) is being trapped.
    3) The difference in the warming of the NH and the SH again proves that it is not the the increase in CO2 that is contributing to it. Namely the CO2 conc. is quickly everywhere the same on earth due to wind and diffusion. Therefore the warming should everywhere be the saem – if an increase in GHG’s were doing it.
    4) The most likely cause that I find for some entrapment of heat in the NH is that it is due to additional vegetation.Namely if you look at my results of Tandil in Argentina, where there has been substantial de-forestation, you find it is actually cooling. In Norway and Scandanavia where there has been an increase in forests, there it is warming.

    So, I think, yes, the increase in vegetation does trap some heat, leading to some increase in the average temperature.The question is how much? Why do they bring CO2 in the equation when clearly it has nothing to do with it, apart perhaps from working as an accelerator for growth. Could this warming not be easily determined in real big greenhouses?

  40. It is not possible to generalize climate throughout the Miocene. Sequence stratigraphy has been used to develop a detailed sea level record, and it shows global swings as large as 250 meters. It is assumed the sea level changes are driven by changes in glacial mass. Clearly, the climate had strong drivers other than CO2, and global temperatures fluctuated through a broad range.

    https://picasaweb.google.com/116116026591418437533/MioceneSeaLevelCurve?authuser=0&authkey=Gv1sRgCMrRp7nErsyUbw&feat=directlink

  41. Hi Willis,

    if you did a careful analysis of my tables

    http://www.letterdash.com/HenryP/henrys-pool-table-on-global-warming

    -suggest you make hard copies -
    you can make a no. of interesting observations

    1) modern warming appears to be driven by an increase in maxima, not minima. It is the increase in maxima that happen during the day that drives up the average temp. and also that of the minima.
    If it were minima (that happen during the night) pushing up the average temp.s we should agree that an increase in GHG’s was the cause of it. As it stands at the moment we have to conclude that the warming of our planet was largely natural.
    2) Maxima increased both in the SH and the NH but if you look at average temps. (= Means) it appears that the global warming is not really global. It would seem that in the NH, which has most of the landmasses, some of the additional heat (most probably caused by more sunshine and/or less clouds) is being trapped.
    3) The difference in the warming of the NH and the SH again proves that it is not the the increase in CO2 that is contributing to it. Namely the CO2 conc. is quickly everywhere the same on earth due to wind and diffusion. Therefore the warming should everywhere be the saem – if an increase in GHG’s were doing it.
    4) The most likely cause that I find for some entrapment of heat in the NH is that it is due to additional vegetation.Namely if you look at my results of Tandil in Argentina, where there has been substantial de-forestation, you find it is actually cooling. In Norway and Scandanavia where there has been an increase in forests, there it is warming.

    So, I think, yes, the increase in vegetation does trap some heat, leading to some increase in the average temperature.The question is how much? Why do they bring CO2 in the equation when clearly it has nothing to do with it, apart perhaps from working as an accelerator for growth. Could this warming not be easily determined in real big greenhouses with and without plants?

  42. Robert of Ottowa wrote: Models are usful tools to assist thinking about a problem; they are qualitive in nature. No weight shold be given to their quantative outputs.

    It depends on how accurate they are, what Willis calls “lifelike”. Dosing regimes for drugs are based on well-tested models; space exploration is based on well-tested models.

  43. Thanks again Willis for a another clear-headed look at some climate numbers. Someone mentioned above the ability of forests to control their temperature. Here’s an abstract:
    From Canada to the Caribbean: Tree leaves control their own temperature
    June 11th, 2008
    The temperature inside a healthy, photosynthesizing tree leaf is affected less by outside environmental temperature than originally believed, according to new research from biologists at the University of Pennsylvania.
    Surveying 39 tree species ranging in location from subtropical to boreal climates, researchers found a nearly constant temperature in tree leaves. These findings provide new understanding of how tree branches and leaves maintain a homeostatic temperature considered ideal for photosynthesis and suggests that plant physiology and ecology are important factors to consider as biologists tap trees to investigate climate change.
    Tree photosynthesis, according to the study, most likely occurs when leaf temperatures are about 21°C, with latitude or average growing-season temperature playing little, if any, role. This homeostasis of leaf temperature means that in colder climates leaf temperatures are elevated and in warmer climates tree leaves cool to reach optimal conditions for photosynthesis. Therefore, methods that assume leaf temperature is fixed to ambient air require new consideration.
    “It is not surprising to think that a polar bear in northern Canada and a black bear in Florida have the same internal body temperature,” Brent Helliker, professor of biology in the School of Arts and Sciences at Penn, said. “They are endothermic mammals like us ,and they generate their own heat. However, to think that a black spruce in Canada and a Caribbean pine in Puerto Rico have the same average leaf temperature is quite astonishing, particularly since trees are most definitely not endothermic. Our research suggests that they use a combination of purely physical phenomena — like the cooling from water evaporation or the warming caused by packing a lot of leaves together — to maintain what looks like leaf-temperature homeostasis.”
    Leaf temperature, cooled by the physiological and morphological techniques of evaporation, leaf angle or reflection and heated by a decrease in evaporation and an increase in the number of leaves per branch, can now be considered adaptations towards achieving homeostasis. Researchers do not suggest that tree canopies maintain a constant temperature through a day or a season, but rather that this ideal temperature is a long-term target value.
    The research, published online in this week’s Nature, contradicts the longstanding assumption that temperature and relative humidity in an actively photosynthesizing leaf are coupled to ambient air conditions. For decades, scientists studying climate change have measured the oxygen isotope ratio in tree-ring cellulose to determine the ambient temperature and relative humidity of past climates. The assumption in all of these studies was that tree leaf temperatures were equal to ambient temperatures.

    http://www.sciencecentric.com/news/article.php?q=08061131

  44. Willis, as you know! Green plants are reflecting only green light and are absorbing the red and blue frequencies of the light spectrum, the chemical responsible for the absorption of light is called Chlorophyll, and it is this chemical that makes the plant appear green, and as our sun is more of a green-yellowish star, green plants do in fact radiate heat albeit mostly in the green frequencies of the spectrum, here’s a thought, the amount of heat radiating from an Aloe Vera plant should be easy to work out, simply measure the amount Chlorophyll per square centimeter and measure the wattage of between 520 – 565nm wavelength from the sun etc… then do some modeling, An interesting hypothetical Questions would be; Does the addition of more Chlorophyll per square centimeter increase the amount of heat radiating from an Aloe Vera plant?

    And come to the conclusion that more Chlorophyll equates to more radiative heat and more radiative heat makes for a better habitat for living creatures and more creatures equal vital Co2 and more Co2 equates to more healthy greener plants and so on…

    It’s lucky humans and other creatures came along and evolved to live in an oxygen and nitrogen atmosphere as plants have very nearly used up the entire supply of Co2.

    (Note flowers turn red, pink and blues to absorb light from the green part of the spectrum, and therefor as a consequence die off before bearing seed)

    “Imagine an Alien Planet…

    One common question in Biology regarding plant life is to imagine an alien planet with a green sun. Would the plant life on that planet still be green? Naturally, through evolution we would expect the plant life to adapt to absorb whatever available light they can so if the main light source is dominantly green, the plant would almost definitely not be green in colour itself. In fact you could imagine the plant would be pink in order to fully absorb the green wavelengths.”

    (NOTE: the first plants evolved in the oceans and are thought to have been purple)

    A Purple Sun

    “There are also some theories that when photosynthesis first developed our oceans were purple and our sun was purple. This would explain the absence of a green absorbing Chlorophyll in plants if this were true. It’s also worth noting that some plant do in fact have purple or very dark leaves which would suggest some species of plant do make an effort of absorbing different light waves although green coloured plants remain the most dominant type.”

    I didn’t know that there are theories that our sun was purple, have you heard of these?

    http://www.whycenter.com/why-are-plants-green/

  45. @John Day:

    Sorry, I posted my comment while yours was in moderation it seems. CAM was the first thing that jumped out at me when I saw the Aloe.

    We can’t expect all plants to behave the same way – if Aloe was human, it would be a human who couldn’t sweat. How hot would a human get in strong sunlight if unable to sweat?

  46. Sorry to stray off topic, but I was flabbergasted by something I just read:

    http://online.wsj.com/article/…..32438.html

    The most flabbergasting part; our energy policy is based on fantasy:

    When it was Mr. Hamm’s turn to talk briefly with President Obama, “I told him of the revolution in the oil and gas industry and how we have the capacity to produce enough oil to enable America to replace OPEC. I wanted to make sure he knew about this.”

    The president’s reaction? “He turned to me and said, ‘Oil and gas will be important for the next few years. But we need to go on to green and alternative energy. [Energy] Secretary [Steven] Chu has assured me that within five years, we can have a battery developed that will make a car with the equivalent of 130 miles per gallon.’” Mr. Hamm holds his head in his hands and says, “Even if you believed that, why would you want to stop oil and gas development? It was pretty disappointing.”

  47. Sorry, will type it in and see if it works:

    http://online.wsj.com/article/SB10001424052970204226204576602524023932438.html

    The title of the article is:

    “How North Dakota Became Saudi Arabia
    Harold Hamm, discoverer of the Bakken fields of the northern Great Plains, on America’s oil future and why OPEC’s days are numbered.”

    Thanks for allowing the OT post. I believe it is important to know how the two Nobel Prize winners are concocting our energy policy.

  48. Bill Illis says:

    “The difference is the lower Albedo of the Earth’s surface since it was primarily low-Albedo forests in this period and the only high-Albedo ice in the period was in Antarctica which was probably only a third glaciated at this point (sea ice in the winter of course).”

    Actually this is only true for the early Miocene. Antarctica became completely glaciated about 14 nillion years ago in the Middle Miocene, and everything points to that at least East Antarctica has never been deglaciated since. West Antarctica has probably been partially deglaciated at times (last probably during MIS 31 about a million years ago), but never to the point of having significant vegetation.

  49. Doug,

    It’s unreal, ain’t it? What about the part where half a dozen oil companies are facing criminal charges for allegedly causing the deaths of 28 nondescript birds. But the wind turbines at Altamont Pass, up the road from me, are killing scores of golden eagles and nothing happens. What surprises me most is how those eagles manage to splatter themselves on turbine blades that are stationary most of the time. Every time I drive through there it pains me to see most of the windmills standing there, nothing more than statues, monuments representing the benefits of government subsidies.

  50. Being “life like” is not a measure of a models usefulness.

    Usefullness can only be assessed in the presence of a clearly (quantified) stated and well defended purpose.

    For example, if our purpose is designing flights controls for an air to air missile we will want to use a 6DOF model of the missile. Even that model is not life like, but it is good enough for the stated purpose. If we want to understand the dynamics of separation from the air vehicle at high angles of attack ( in a post stall regime ) we will need even more fidelity. However, if we are trying to evaluate a missile effectiveness in combat, we may use a 3DOF model, not very lifelike at all,
    but it fits the intended purpose. If we are trying to size a weapons bay, we dont need anything more than the size and weight.

    You dont judge the usefullness of a model without first defining and quantifying the purpose for which you need it. That’s been largely neglected in GCM development. Judging them with unquantified criteria is just as suspect as building them without these criteria to begin with

  51. If the earth’s surface was arid with no vegetation, I think the climate would be hotter, not colder. Thus albedo is not the whole story. In the early phanerozoic, the spread of plants on land was associated with a big fall, not rise, in global temperatures – and this was good for multicellular life in general. The spread of plants, their transpiration of water and making of soil, caused much more water to be retained on land, propelled the hydrological cycle and thus cooled, not warmed, the planet.

    There is a reason why the word arid is associated with dry and hot. It is that arid environments are dry and hot. The overall planetary effect of plants is cooling, and it is via the remarkable compound water with its extraordinary heat capacity.

    The paper reviewed by Willis snatches at plant albedo as a reason for a warm planet depite low CO2. But plant transpiration makes cloud which, as we now know from recent discussions here at WUWT, dominates planetary albedo and outgoing radiation.

    Nice try but try again.

  52. Willis:

    As always, your reports are provocative and worth reading — and thinking about.

    Your comment that “Me, I think that climate sensitivity is an illusion based on a misunderstanding of how climate works” reminds me of Roger Pielke Sr.’s work along those lines — for example,

    http://pielkeclimatesci.wordpress.com/2011/09/19/new-paper-land-useland-cover-changes-and-climate-modeling-analysis-and-observational-evidence-by-pielke-sr-et-al-2011/

    Pielke has written on numerous occasions that he thinks that land use/land cover changes are at least as important as CO2 emissions in driving climate change. One of these days, I need to read Pielke’s stuff on this carefully.

    Best regards,
    Pete Tillman

  53. FWIW, Miocene marine fossil assembleges from Maryland’s Calvert Cliffs seem consistent with a slightly warmer climate than today. e.g. crocodiles.

  54. John Day says:
    October 1, 2011 at 4:23 am

    @Will
    > Plants convert Sunlight into matter. Ergo they are a
    > cooling feedback not a warming feedback.

    Yes, I think this is generally true. I first noticed this years ago while scooting around town on a moped, in Florida, The air temperature around groves of trees felt cooler then air around open lots. Vegetation tends to absorb energy, not scatter it. (We get the energy back when we eat the plants or burn them for warmth).

    Aloe vera plants are somewhat unusual in that they they exhibit Crassulacean acid metabolism or “CAM” photosynthesis. So they release CO2 during the day and absorb it at night, opposite of most green plants temperate climates. This allows the plant to conserve its water content (95%) by closing its stomata (pores) during the day when its hottest. This lowers the transpiration of its water content.

    http://en.wikipedia.org/wiki/CAM_photosynthesis

    So, Willis, at what times during the day or night did you notice this thermal phenomena?

    Mid-afternoon. Fascinating about the CAM photosynthesis. This would account for part of the reason that the plant was so hot.

    w.

  55. ted says:
    October 1, 2011 at 8:03 am

    Fascinating article.

    Willis, you appear to have made an error in comparing climate sensitivities. The IPCC ranges include water vapor feedback, whereas your 1.15 C estimate is based only on albedo change. Apples and oranges, no? Further: Knorr et al attributed half of the 3K Miocene warming to the water feedback (also clear from the abstract).

    You haven’t thought this all the way through. Although there is more temperature change when you include the water vapor, there is also more forcing change … so the ratio of the two (climate sensitivity) changes very little. So whether you calculate using just the albedo figures, just the water vapor figures, or the combination of both, the answers are all very close to the figure I quoted.

    w.

  56. Um, Willis, in the framework of the very study you’re invoking, you’re mixing up forcing and feedback.

  57. Scarlet Pumpernickel says:
    October 1, 2011 at 6:33 am (Edit)

    Just like to make the point that the plant in the picture is not Aloe Vera. It is an Aloe, Aloe Vera is a different plant http://4.bp.blogspot.com/_pUjFBZdt6fI/TK6OZ8tD-mI/AAAAAAAAABQ/Wf7gTHAk_CY/s1600/Aloe-Vera-Plant.jpg which is more like a single head. The above plant is an Aloe, but I’m not sure exactly which one it is. eg http://en.wikipedia.org/wiki/List_of_Aloe_species there are many species of Aloe, and the pictured one is not Aloe Vera….

    Scarlet, my thanks, always more to learn. Upon investigation, the plant at my house looks the most like the Aloe succotrina of any of the aloes I’ve seen pictured.

    w.

  58. Ted says: [entire unedited post follows]
    October 1, 2011 at 7:59 pm

    Um, Willis, in the framework of the very study you’re invoking, you’re mixing up forcing and feedback.

    Um, Ted, could you please be a little bit more vague?

    w.

  59. Earlier I said “They say half is the albedo change and half is the water vapor feedback. This means that the sensitivity including feedback is 2.3 degrees per doubling, not 1.15. I don’t know what Willis is talking about.”
    This is exactly what Ted said at about the same time. I understand exactly what Ted is talking about.

  60. There is a reason why the word arid is associated with dry and hot. It is that arid environments are dry and hot.

    It’s a misconception that arid places are hot.

    At the same lattitude a humid place will be hotter than an arid place over a year.

    A while back, I compared annual average temperatures for places that reported the highest temperatures ever recorded (all in deserts) with humid tropical locations.

    In all cases the humid locations had annual average temperatures at least 3C higher than the arid locations.

  61. Am I alone in seeing bunches of people trying to compare the world inside the canopy to the world outside the canopy? The heat from the aloe vera is the solar energy not needed by the plant. It bounces and can be felt from a distance. That is quite different from what happens under the aloe vera canopy where shade is available, IR is absent, and what ever soil moisture might be available is doing what ever it does.

    It is the same when walking across grass with bare feet. What energy is not needed by the grass is rejected, the blades throw shadows, moisture that close to the ground is rampant, and unlink the aloe verde which creates CO2 at night, the grass is cranking it out all day long. Along with humidity.

    Want to walk under a rain forest canopy? Same as above. Inside the canopy all is cool, moist, while all outside the canopy is gobs of unneeded energy.

    Here’s a kid younger than most of my shoes that gets it right:

    http://www.amnh.org/news/2011/08/linking-trees%E2%80%99-fibonacci-sequence-to-solar-power-wins-student-a-young-naturalist-award/

    Plants are not stupid.

  62. dp says:
    October 1, 2011 at 10:49 pm

    “and unlink the aloe verde which creates CO2 at night, the grass is cranking it out all day long. Along with humidity.”

    Somewhat like Willis there, you appear to have things upside-down.

    First, the point about the Aloe plant is that it uses CO2 at night, while most other plants use it during the day.

    Photosynthesis requires sunlight you see. Therefore grass is not cranking it out (CO2) all day, it is consuming it and locking it away all day.

    Finally, and this is a point that I cannot emphasise strongly enough, humidity is not something you should associate with heat. This is one of the most pivotal logical fallacies of the so called “greenhouse effect” hypothesis. Water vapour (humidity) transports heat. It does not produce heat. When it is cold and humid we don’t call it humid, we call it damp, but it is still humid. In cold weather humidity has the exact opposite effect as in hot weather. But we don’t call it humid we call it damp and cold. But it is still humid. This is pure semantics.

    Through semantics we associate humid conditions with heat and through the use of such semantics which are based on logical fallacies, the “greenhouse effect” hypothesis has been built.

    The “greenhouse effect” hypothesis is built on many such logical fallacies. In the case of humidity, the logical fallacy is that water vapour is a so called “greenhouse gas” because humidity is always fallaciously associated with warming.

    Try spending the day at the beach in St. Ives Cornwall UK on a wet windy day in January, and take a hygrometer to check how humid it is.

    Water vapour transports heat. In a realty were the 2nd Law of Thermodynamics dominates, this transportation of heat is always a cooling mechanism. It makes no difference if you are on the beach at Cayolargo, Cuba in the middle of September sweating your tits off or on the beach at St. Ives Cornwall in the middle of January freezing your tits off, humidity cools the planet.

    Perception is not reality.

  63. phlogiston says:

    “There is a reason why the word arid is associated with dry and hot. It is that arid environments are dry and hot”

    Like the Dry Valleys of Antarctica you mean?. They are the most arid environment on the planet.

  64. Philip Bradley, tty

    OK arid and cold can go together, and albedo cannot be written off. My point was that on a global scale land vegetation has built humic soils and retained water on land, in the process extending the hydrological cycle, making more cloud and exerting a cooling effect, as in the Devonian and Carboniferous where temperatures fell as trees evolved and spread.

    Bill Illis above presented 2 mechanisms causing warming in the low-co2 Myocene – forest albedo and changed ocean currents, particularly the interruption of the Antarctic circumpolar current. Which of these is most important? It is not clear if albedo is the dominant or a minor factor.

    Interestingly as Bill also axplained, reducing CO2 has clearly stressed the biosphere as evidenced by the adaptive evolution of monocot grasses with their higher carbon efficient c4 photosynthesis. The spread of grasslands in the palaeocene-neocene has increased albedo,and contributed to the current cooling and glaciation. This is an indirect cooling effect of CO2 but it is biological, not physical.

  65. There is sensitivity to each extra forcing.

    And then there is sensitivity to CO2/GHGs.

    From 24 million years ago to 5 million years ago (the Miocene), the CO2 sensitivity is Zero or Negative.

    It warms when CO2 falls, it warms when CO2 stays the same at 250 ppm, It cools when CO2 increases. 85% of the time, CO2 is below 280 ppm.

    I’ve got Albedo at 27.6% in the wamest parts of the Miocene based on vegetation, desert, sea ice, land glaciation and continental position patterns (I’ve built an Albedo model) which would be an increase in solar forcing of 7.6 W/m2: in the later Miocene, an increase in solar forcing of 2.0 W/m2. CO2 forcing at -0.4 W/m2 thoughout most of the Miocene.

    I guess that puts a high sensitivity value on forcings (without feedbacks) in general but tells us nothing about CO2 sensitivity except that it played no role in the warm Miocene (which is the same story in the rest of the paleoclimate).

  66. Imagine a volcanically active period. Not a lot of vei8s but a lot of vei6 eruptions and a lot of mid ocean activity. That will be a lot of CO2.

    Now imagine a very active plant regime such that it fixes most of the CO2 as it comes out.

    If we see the land and ocean based plant life in light of the same life around deep ocean vents, then the analogy is that the land and ocean plant life FIXES CO2 with the help of sunlight, rather than fixing the chemicals around the deep ocean vents.

    Life divorced itself from the vents a long time ago, but it still needs something from those vents.

    Without CO2 or some other matter feed, life will shut down.

    The Earth is one giant chemical engine.

  67. steven mosher says:
    October 1, 2011 at 12:21 pm

    “Being “life like” is not a measure of a models usefulness.

    Usefullness can only be assessed in the presence of a clearly (quantified) stated and well defended purpose…..

    You dont judge the usefullness of a model without first defining and quantifying the purpose for which you need it. That’s been largely neglected in GCM development…..”

    BUT But but, the usefulness of the CAGW models WAS very clearly defined. The objective was to stampede the scientifically ignorant into giving up more wealth and freedom to an international organization intent on promoting “Global Governance”

    It is no coincidence that Maurice Strong the father of Global Warming (First Earth Summit 1972) is also a member of the UN Commission on Global Governance, special advisor to UN Secretary General Boutros Boutros-Ghali, Senior Advisor to UN Secretary General Kofi Annan; Senior Advisor to World Bank President James Wolfensohn; Chairman of the Earth Council; Chairman of the World Resources Institute (WRI); Co-Chairman of the Council of the World Economic Forum…..

  68. Austin says:
    October 2, 2011 at 8:15 am

    Without CO2 or some other matter feed, life will shut down.

    Here’s a paper (Causes and timing of future biosphere extinctions, S. Franck et al. 2006) which spells out how:

    http://www.biogeosciences.net/3/85/2006/bg-3-85-2006.pdf

    To quote from the conclusion:

    Eucaryotes and complex life become extinct because of too high surface temperatures in the future. The time of extinction is mainly determined by the upper temperature tolerance limit of these life forms. The ultimate life span of the biosphere is defined by the extinction of procaryotes in about 1.6 Gyr because of CO2 starvation. Only in a small fraction (1.3–1.7 Gyr) of its habitability time (6.2 Gyr) can our home planet harbour advanced life forms.

    “Eat, drink and be merry…”

  69. Glacial phases tend to be drier, colder and windier than interglacials, as at present. Aridity is not necessarily associated with hotter weather or climate.

  70. Somewhat like Willis there, you appear to have things upside-down.

    I realized that just after hitting the send button. I reversed my logic. With WordPress what goes wrong on the internet stays wrong on the internet.

    I don’t think I got the logic wrong in the perspective regarding the observer’s location inside vs outside the canopy.

  71. “I thought about the curious ability of plants to heat the air around them”

    Let me get this straight. It’s the plants that are causing Global Warming, right?

    Then let’s chop them all down and burn them. Eliminate them all. Problem solved.

  72. @phlogiston says:
    October 2, 2011 at 8:46 am

    That’s a fascinating article. Life had a hard time getting going because it was too hot, until finally the biomass became so huge it changed the global temperature to be far cooler. Ultimately, life dies out on earth because 1) CO2 is depleted, and 2) the aging Sun gets far brighter, raising the temperatures to above the boiling point of water. Fortunately we have a billion years or so to enjoy the cool, green hills of earth.

  73. Yes the Franck paper is certainly food for thought, possibly of a melancholy or morbid kind.

    This piece by Willis could equally have been called “Myocene Myopia”. Have you noticed that officially sanctioned climate palaeo-climate research never looks at the Myocene? It either looks at the last 2 or 3 interglacials or it jumps back 55 million years to a brief warming episode from which a CO2 story can be woven.

    Why is the Myocene from 24 to 5 MYa such a glaring omission, such a blind spot? Why the silence on this period?

    Bill Illis explains clearly why – the Myocene refutes the CAGW hypothesis by the clear absence of any warming influence of CO2 – or any influence of CO2 on climate at all. During the Myocene:

    “It warms when CO2 falls, it warms when CO2 stays the same at 250ppm, and it cools when CO2 rises.”

  74. My favorite factoid about the Miocene is that 10 million years ago, there was 50 different species of Apes on the forest planet. It was, indeed, Planet of the Apes. One of them gave rise to us.

  75. Jeff Id says:
    October 3, 2011 at 6:54 pm
    ——-

    Touché (but probably at least an isolated group).

    Gorillas, Chimps, and Bonobos also came from this group.

  76. At ten million years ago, the Asian & African great apes had already diverged, both groups refugees from temperate Eurasia, forced into the tropics by global cooling & the spread of grasslands at the expense of forests. A few million years later, one group of African great apes, responding to the spread of grasslands even into the tropics (aided by the formation of the Great Rift Valley) decided that if you can’t beat savannahs, you should join them, & became us.

    On another topic, even today, in a warm interglacial, the high Arctic is a dry desert, with less than eight to ten inches of precipitation per year.

    In response to another thread on this productive topic, it’s not just the Miocene which presents problems for advocates of CO2 as the main driver of climate change, but also the Holocene, Pleistocene, Oligocene, Eocene & Paleocene Epochs, not to mention the Cretaceous, Jurassic, Triassic, Permian, Carboniferous (!), Devonian, Silurian, Ordovician (!) & Cambrian Periods.

  77. Genetic analysis shows that the common ancestor of humans, gorillas and chimps / bonobos lived about 7 million years ago. However discoveries of human ancestors further and further back in time, nearer to this 7 million year branching, surprisingly keep on finding bipedal apes like humans and australopithecines – not the expected old world type ape.

    A hypothesis has been researched by John Gribben and others that the common human / chimpanzee / gorilla ancestor 7 million years ago was in fact still bipedal – something like an australopithecine. And that this proto-human bipedality and growth of brain size was then lost in the fork of the road leading to the present day chimps and gorillas.

    What will we look like in another 7 million years? Our humanity cant be taken for granted. At least WUWT is doing its bit to preserve sentience.

  78. Much of the Arctic receives little enough precipitation to qualify as desert, but how much precisely is hard to say, due to the problems inherent in trying to measure snowfall & to the scarcity of reporting stations.

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