Guest Post by Wim Röst
Water, H2O, determines the ‘General Background Temperature’ for the Earth, resulting in Hothouse and Ice House Climate States. During geological periods the movement of continents changes the position of
continents, oceans and seas. Because of the different configurations, a dominant warm or a dominant cold deep-water production configuration ‘sets’ average temperatures for the deep oceans. Changing vertical oceanic circulation changes surface temperatures, especially in the higher latitudes. During a Hot House State, higher temperatures in the high latitudes result in a high water-vapor concentration that prevents a rapid loss of thermal energy by the Earth.
These three processes, plate tectonics (continental drift), vertical oceanic circulation variability and variations in atmospheric water vapor concentration and distribution, caused previous Hot House and Warm House Climate States. A change in the working of those mechanisms resulted in a transition from the previous Hot House Climate State to the very cold ‘Ice House State’ that we live in now. That change was set in motion by the changing configuration of continents, oceans and seas.
The Earth has known Hothouse periods because of two things. The Earth warmed because of storage of thermal energy in the oceans (H2O) and because a higher quantity of water vapor (H2O) in the air (especially at the poles) prevented the Earth from cooling.
The Earth has known Ice House periods because of a lack of storage of thermal energy in the oceans and because the resulting loss of atmospheric water vapor (especially at the poles) accelerated the cooling until the Earth reached an Ice House State. That is, more thermal energy can be radiated to outer space from the polar regions if they have a lower concentration of water vapor.
In three ways the changing Earth created Hot House Climate States. The first and the most important was the creation of [relatively] warm deep oceans. The second important mechanism was a reversal of the vertical water circulation that resulted in a far more effective distribution of absorbed sun-energy over all latitudes. The third mechanism was the rise in the quantity of water vapor, the main infrared radiation absorbing gas of the lower atmosphere, a rise that prevented strong night and winter cooling especially at the high latitudes. All together the three mechanisms resulted in much warmer average global temperatures during Hot House climate states with far more evenly distributed temperatures over all latitudes. During Hot House (and Warm House) climate states, the whole Earth became lush and green, from the tropics to the poles.
All changes were due to water, H2O. Physics did do the work, no humans involved.
On a geological timescale, the configuration of ‘continents’ and ‘oceans’ determines the general climate state: warm or cold. Continents gave shape to different combinations of oceans and seas. Different configurations of oceans, seas and continents caused the production of warm or cold deep-ocean water.
The temperatures of the deep-ocean set the ‘general background temperature’ for the Earth during different geological periods. Creating warm and cold climate states. Now we are living in an era of long glacials and short interglacials, our present era is an era within an Ice House Climate State.
The temperature of the deep ocean is the main factor. Deep-ocean temperatures from -1 to +3 degrees Celsius, as we have now, keep the Earth in an Ice House State. Slightly warmer deep-oceans with temperatures from 6 to 10 degrees Celsius* bring the Earth to a Warm House or a Hot House Climate State. The underlying system for this switch is characterized by three mechanisms, as discussed below.
1. Warm deep oceans
Warm House and Hot House Climate States were characterized by ‘warm’ deep oceans. ‘Warm’ has been warm in a relative way: as compared to our present ice-cold deep oceans of -1 to +3 degrees Celsius, the ‘warm’ deep oceans of the past probably had average temperatures of 6 to 10 degrees Celsius. As we shall see, this relatively small temperature difference had huge consequences for the global average surface temperature of the Earth and for the Earth’s climate state.
In oceans and seas certain water goes down and other water wells up from the deep oceans, both in huge quantities. Think in terms of a million or more cubic kilometers a year. For the final temperature of the
deep-ocean it is important which water wells down: relatively cold or relatively warm water. Present seas like the Mediterranean, the Red Sea and the Arabian Gulf demonstrate that it is possible to produce warm deep water: in arid regions the local evaporation produces high salinity surface water that is that dense that it goes down (‘sinks’) as warm salty water. After welling down, the warm and now ‘deep’ water is covered by less dense ocean water.
In this way, even in our present Ice House State, the above-mentioned seas produce warm deep water of
around 12 degrees Celsius and more. When the warm deep-water flows back into the oceans, it sinks to depths of 1000 to 4000 meters, depending on the salinity and the density of the local deep ocean. The deep warm and saline water is produced at latitudes where evaporation is higher than rainfall, often around 30 degrees North. Sea surfaces at 30 degrees contain very saline warm water that is still able to ‘float’ because of high water temperatures. But during wintertime this saline surface water cools and sinks.
Shallow, enclosed seas like the Mediterranean still produce warm, deep water, but only have a small surface area. Too small, to get the Earth out of her present Ice House State.
But in the geologic past, fifty- to one-hundred million years ago, those shallow and nearly enclosed seas were very extended at latitudes where they could produce warm deep-water: around 30°N, See Figure 1.
Figure 1: The position of continents, oceans and shallow seas 100 million years ago, according to Christopher Scotese, as shown in this animation.
Because of their large total surface area, these shallow and nearly enclosed seas produced huge quantities of deep warm water. That warm deep-water production warmed the deep oceans that characterized Warm House and Hot House periods, like the Cretaceous.
During those Warm House and Hot House periods there was no dominating cold deep-water production. The poles were cooler than the tropics, but not frozen, because of upwelling warm deep-water. Because of the still relatively low temperatures at the poles, evaporation was low and was exceeded by rainfall, which resulted in relatively fresh surface waters in the polar seas, a freshness that became further enhanced by (fresh) poleward river runoff. Because of the freshness of the surface waters, their density was low. Low density waters don’t sink. Because of that, there was no massive cold deep-water production at the high latitudes during Warm House and Hot House states. This was the second reason why warm, deep water production dominated. Warm, deep oceans were the result, see Figure 2.
Figure 2: Warm and cold deep-water production 100 million years ago, same figure as figure 1, red and blue squares added. In red: the areas around 30 degrees with a supposed massive warm deep-water production. In blue: present cold deep-water production areas, not functioning 100 million years ago: surface waters were too fresh.
2. A reversed vertical water circulation
In our present Ice House State, we find a massive sink of cold water at the higher latitudes. This sinking water is replenished by warm and saline surface water, transported over the surface. Currents like the warm Gulf Stream do the work. However, the present poleward transport consists of a current over only part of the total width of the ocean and using only a minor layer at the surface. Currently, the quantity of warm water transported to the poles is far less than the warm, deep water transport during Warm House and Hot House periods. This is shown below in the figures 3a and 3b.
Figure 3a: Present oceanic transport in the North Atlantic, over latitude 40N, schematic. The red block represents the poleward surface transport by the Warm Gulf Stream. The depth of the surface layer is exaggerated.
Figure 3b: Hot House oceanic transport in the North Atlantic, over latitude 40N, schematic. The big block with relatively warm water represents the deep ocean, transporting warm water pole ward. The volume of warm-water poleward transport is important. In a hot-house scenario it is ocean-wide and ocean-deep. The moderate water at the surface flows from the north pole to 30N, to replenish the sinking waters at 30N. The depth of the surface layer is exaggerated.
Warm, deep water was transported to the poles where at that time deep water was welling up (Golovneva 2000**). The warm water prevented formation of polar ice and the poles stayed ice free, even in winter time. During the winter half year, at the North Pole cold land areas were bordering the relatively warm Arctic Ocean, resulting in a high temperature gradient between the two. The high gradient resulted in strong winds that caused the upwelling of warm deep-water.
The warm polar upwelling and the downwelling at 30N together resulted in a reversed vertical ocean circulation, when compared to the present one. Our present vertical oceanic circulation is shown in figure 4a.
Figure 4a: Present (Ice House) vertical oceanic circulation. North-South transect, simplified, schematic. South Pole at the left (90°S), North Pole at the right (90°N), equator (0°) in the centre.
Present cold deep-water production at the poles dominates the deep oceans. Our present deep oceans are ice-cold, and that cold water is welling up at lower latitudes, cooling the warm surface layer. After upwelling, cool surface waters (shown in orange) are warmed in the tropics and transported poleward over the surface by warm currents.
But, in a Warm House or a Hot House State, the vertical water circulation is the reverse of the circulation as shown in figure 4a. See below, figure 4b.
Figure 4b: Hot House vertical oceanic circulation. North-South transect, simplified, schematic. South Pole at the left (90S), North Pole at the right (90N), equator (O) in the centre.
Warm saline waters went down at 30°N, filling up all the world’s deep oceans. The upwelling warm water at the poles had to flow back to the downwelling areas at 30°N to replenish the downwelling waters. Because surface waters at the poles became fresh and less dense, polar water stayed at the surface when it flowed back to 30N. As compared to the present situation (figure 4a), the vertical circulation in the oceans was reversed during Warm and Hot House periods (4b).
Deep, warm water was not only transported basin-wide and basin-deep but had the advantage that it was not cooled at the surface. For these reasons, this deep redistribution of tropical thermal energy was superior to the present ‘Gulf Stream like’ thermal energy transport over the surface. It was the perfect way to transport absorbed tropical/subtropical energy over all latitudes. The results were higher average surface temperatures and a more uniform climate from the poles to the equator. That is, a smaller pole-to-equator temperature gradient, see Figure 5.
Figure 5: Temperatures per latitude over the Northern Hemisphere for the Maastrichtian period, 72- 66 million years ago. The graphic below is fig. 2 from Golovneva, 2000, see the abstract at the end of the post (Golovneva 2000)**. From the paper: “Temperature gradients for present (continuous line, after Barron (1983)) and the Maastrichtian stage (dotted line).” The dotted line is based on fossil plant evidence.
Source: (Golovneva 2000)
Only a reversed vertical oceanic circulation can create the pole-to-equator gradient that is shown in the figure above, for the Maastrichtian. Notice the lower temperatures around the equator during the Maastrichtian (Warm House) period, as compared to the present period.
Much higher temperatures than todays were not only found at and around the North Pole, but also in Antarctica (Francis and Poole 2002). ***
The very different and more uniform distribution of surface temperatures over the latitudes of the Earth as caused by the oceans had important consequences for the role of water vapor, our main surface infrared radiation absorbing gas.
3. Water Vapor effects
Together, the warm deep-water production and the reversed circulation created temperatures at the high latitudes that were much higher than today’s minus 30 to minus 50 degrees Celsius during winter time. During Warm House and Hot House periods, even in winter time temperatures above zero were normal at the poles and for summer time, moderate temperatures were found (Golovneva 2000)**.
The much warmer poles and middle latitudes lifted the average temperature of the Earth.
As surface temperatures rose, the rate of evaporation over the oceans at the higher latitudes rose exponentially, resulting in a huge rise in water vapor content in the regional lower atmosphere. Water vapor is by far our main infrared radiation absorbing gas. Because of the warm deep-water production and because of the reversed circulation during Hot House periods, water vapor became also abundant over the middle and high latitudes. Reducing the speed of heat loss to outer space. And resulting in higher surface temperatures than could have been caused by only polar upwelling of relatively warm deep-water. Especially during night time and during the long dark polar winters, the water vapor effect enhanced the polar temperature increase that is initially caused by the reversed circulation and the relatively warm deep-water.
Figure 6: Water vapor content over latitudes, in our present Ice House State (on the left) and water vapor in a Warm House / Hot House State (on the right). North Pole on top, the Antarctic at the bottom of the figures.
Clearly, the Earth loses more energy in an Ice House State because of the lower content of water vapor over the middle and higher latitudes, resulting in a strong cooling for the Earth as a whole. Therefore, our present average temperature for the Earth as a whole is low.
The massive heat loss at the poles in combination with the poleward transport of very saline surface water results in the massive production of ice-cold, deep water that has been filling the present deep oceans. Elsewhere, upwelling deep cold water cools the surface, even far from the poles. Lowering average temperatures.
During a Hot House / Warm House State, a large quantity of water vapor over the high latitudes prevents the fast loss of thermal energy at the poles, leading to a higher temperature level for the poles and for the Earth as a whole. The higher temperature level at the poles also prevents ‘Ice and Snow albedo cooling’. A Hot House / Warm House State was the result.
Warm periods are characterized by a high stability. During Hot House periods climates were also very equal over most of the surface of the Earth. A warm Earth meant a stable, equal and in general moderate Earth.
During Hot House / Warm House climate states, the higher water content of the atmosphere over the middle latitudes also enhances rainfall over the poles, creating lower salinity ocean surfaces at the high latitudes that prevent cold deep-water production.
Fresh polar waters stabilized the deep-warm water heating system over the whole Earth as thermal energy was absorbed by the oceans at low latitudes. Water stores and transports huge quantities of thermal energy, especially if distributed ocean-wide and ocean-deep. Even if transport is very slow, it results in a huge redistribution of thermal energy over latitudes.
Because of the role of water vapor, deep, warm oceans did not need to be very warm to create ice free poles. A moderate rise in deep-water temperature and a reversed circulation were enough to create the right circumstances for an important rise in water vapor content over the middle and high latitudes.
Altogether, the ‘Triple H2O System’ prevented a strong heat loss at the poles and created a big rise in temperature, which resulted in higher average temperatures for the Earth as a whole.
3 x H2O + 1: Water vapor creates ‘weather’
The far more evenly distributed temperatures over all latitudes together with the enhanced water vapor content at the higher latitudes also changed the whole atmospheric system of Warm House and Hot House eras. Low- and
high-pressure systems, wind direction, wind speed, evaporation, convection, clouds and cloudiness, etc., all hanged. All were acting completely different as compared to our present atmospheric system. The more equal circumstances over latitudes reduced the pole-to-equator temperature gradient.
Together with ‘temperature’, it is water vapor, H2O, that creates the daily and seasonal variations in the atmosphere that we call ‘weather’. And because ‘climate’ is defined as the average of 30 years of ‘weather’, it is the water vapor molecule, H2O, that changes climate.
Water vapor creates differences in the density of air, like salinity creates differences in the density of ocean water. Both water vapor and salt create the movements in the two ‘fluids’ that create our weather and our climate, the oceans and atmosphere. Water vapor and temperature rule convection in the air and salt and temperature rule convection in the oceans.
In short, the system of ‘weather’, ‘climate’ and ‘climate states’
Oceans create ‘climate states’ and in the atmosphere, ‘weather’ is created by water vapor. ‘Orbit’ creates seasons. Slight differences in orbit create glacials and interglacials in our present Ice House State. Stadials (or glacial periods) start when the temperature of the oceans cools enough that snow and ice can start enhancing the Earth’s albedo. The lower temperatures cause much lower water vapor concentrations in the higher latitudes. Less water vapor in the air cools the poles during night time and during the winter, enhancing ice and snow effects and increasing the pole-to-equator temperature gradient. Weather changes, and climate changes.
All this happens in a certain setting of continents and oceans and each specific continental configuration for every geological era results in a set of possibilities for weather and climate. This set of possibilities is limited by a ‘general background temperature’ that mainly depends upon the temperature of the deep oceans.
Warmer deep-ocean water, a reversed vertical oceanic circulation and a far higher quantity of atmospheric water vapor over the higher latitudes, together create Warm House and Hot House Climate States. ‘Water’ is the main constituent of the three mechanisms: H2O, H2O and H2O.
Another positioning of continents and oceans in previous geological eras enabled a dominate warm deep-water production. Nearly enclosed seas and shallow seas at 30N produced warm and very saline water that, because of its high density, filled the deep oceans. Over the poles, a higher rainfall than evaporation caused fresh polar surface waters, this prevented massive, deep cold-water production. Warm deep-water production dominated.
Warm deep-water production at 30N resulted in warm upwelling at the poles and in a reversed vertical water circulation in the oceans. Higher temperatures at the poles and the mid-latitudes were the first result. In Warm and Hot House climate states, the poles stayed ice-free and polar winter temperatures became very moderate.
Over the higher latitudes, during Hot House periods the quantity of the most important infrared radiation absorbing gas in the atmosphere, water vapor, increased because of higher polar surface temperatures. That polar water vapor prevented a large heat loss for the Earth as a whole, warming the Earth. Water vapor also kept the poles and the higher latitudes warm. And because of the strong poleward rise in temperatures, the average temperatures of the Earth rose to what we know now as the higher average temperatures of Warm House and Hot House Climate States.
Because of those three H2O mechanisms Hot House Climate States developed in periods when the positioning of continents enabled a dominant warm deep-water production and prevented a massive production of cold deep-water. Nearly all the past 250 million years were [much] warmer than the Ice House State of the last 3 million years. The disappearance of warm, deep-water producing seas was the cause, in combination with the geologically recent development of a system of deep-cold-water production near the poles.
Simple physics did the work. All natural. Triple H2O.
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About the author: Wim Röst studied human geography in Utrecht, the Netherlands. The above is his personal view. He is not connected to firms or foundations nor is he funded by government(s).
Andy May was so kind as to read the original text and improve the English and text where necessary. Thanks again Andy.
* According to this Bill Illis, graphic:
** Source of the data:
(h/t Philip Mulholland)
*** Cretaceous and early Tertiary climates of Antarctica: evidence from fossil wood
Francis, Jane and Imogen Poole
Fossil wood is abundant in Cretaceous and early Tertiary sediments of the northern Antarctic Peninsula region. The wood represents the remains of vegetation that once grew in high palaeolatitudes when the polar regions were
warmer, during former greenhouse climates. Fossil wood is a unique data store of palaeoclimate information. Analyses of growth rings and anatomical characters in fossil wood provide important information about temperature, rainfall, seasonality and climate trends for this time period in Antarctica. Climate signals from fossil wood, supported by sedimentary and geochemical evidence, indicate a trend of cool climates during the Early Cretaceous, followed by peak warmth during the Coniacian to early Campanian. Narrower growth rings suggest that the climate cooled during the Maastrichtian and Palaeocene. Cool, wet and possibly seasonal climates prevailed at this time, with tentatively estimated mean annual temperatures (MATs) falling from 7°C to 4–8°C respectively, determined from dicotyledonous (dicot) wood anatomy. The Late Palaeocene/Early Eocene was once again warm, with estimated MATs of 7–15°C from dicot wood analysis, but conditions subsequently deteriorated through the latter part of the Eocene, when cold seasonal climates developed, ultimately leading to the onset of Cenozoic ice sheets and the elimination of vegetation from most of Antarctica. Source.
Francis, Jane and Imogen Poole.2002. „Cretaceous and early Tertiary climates of Antarctica: evidence from
fossil wood.” Palaeogeography, Palaeoclimatology, Palaeoecology 182 (1-2). https://www.sciencedirect.com/science/article/pii/S0031018201004527.
Golovneva, Lena. 2000. The Maastrichtian (Late Cretaceous) climate in the Northern Hemisphere.” Geological
Society, London, Special Publications 181: 43-54.