Climatology – CO2 and the Energy Budget

Talking about the weather has always been a popular pastime.

Reading about climate has been cyclically growing in popularity for the last 140 years.

The Role of the Sun in Climate Change – Oxford University Press – 1997
Douglas V. Hoyt and Kenneth H. Schatten

Therefore, it is unsurprising that the influence of carbon dioxide upon the Earth’s climate was discussed as far back as the 1920s.

We have already seen that the amount of carbon dioxide gas in the atmosphere has a decided climatic importance.

Moreover, there can be little doubt that the amount of that gas in the atmosphere varies from age to age in response to the extent to which it is set free by volcanoes, consumed by plants, combined with rocks in the process of weathering, dissolved in the ocean or locked up in the form of coal and limestone.

The main question is whether such variations can produce changes so rapid as glacial epochs and historical pulsations.

Climatic Changes: Their Nature and Causes – Yale University Press – 1922
Ellsworth Huntington and Stephen Sargent Visher
http://www.gutenberg.org/ebooks/37855

Thankfully, there were good scientists around in the 1920s to address the question of carbon dioxide and the Earth’s climate.

William Jackson Humphreys (February 3, 1862 – November 10, 1949) was an American physicist and atmospheric researcher.
…
He worked in the fields of spectroscopy, atmospheric physics and meteorology.

In the field of spectroscopy he found the shift of spectral lines under pressure.

In atmospheric physics he found a very good model for the stratosphere in 1909.

He wrote numerous books, including a textbook titled Physics of the Air, first published in 1920 and considered a standard work of the time, though it was last published in 1940.

He also held some teaching positions at universities.

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

William Jackson Humphreys emphasised the predominant role of water vapour and stated that a doubling [or halving] of CO2 “could not appreciably change the average temperature of the earth”.

Page 565
Hence, finally, doubling or halving the amount of carbon dioxide now in the atmosphere, since this would make but little difference in the pressure, would not appreciably affect the total amount of radiation actually absorbed by it, whether of terrestrial or of solar origin, though it would affect the vertical distribution or location of the absorption.

Again, as explained by Abbot and Fowle, the water vapor always present in the atmosphere, because of its high coefficients of absorption in substantially the same regions where carbon dioxide is effective, leaves but little radiation for the latter to take up.

Hence, for this reason, as well as for the one given above, either doubling or halving the present amount of carbon dioxide could alter but little the total amount of radiation actually absorbed by the atmosphere, and, therefore, seemingly, could not appreciably change the average temperature of the earth, or be at all effective in the production of marked climatic changes.

Page 566
Suffice it to anticipate, here, the general conclusion that while variations in the amounts of carbon dioxide in the atmosphere may have somewhat modified our climates, it, probably, never was the controlling, or even an important, factor in the production of any one of the great climatic changes of the past, nor can be, of any great climatic change the future possibly may bring.

Physics Of The Air – 1929 – McGraw-Hill Book Company
W J Humphreys
https://archive.org/details/physicsoftheairs032485mbp

Humphreys quantifies “not appreciably” to mean plus [or minus] 1.3 C.

Page 602
Assuming that the present amount of carbon dioxide in the stratosphere absorbs 1 per cent of the solar radiation and 10 per cent of the outgoing earth radiation (values that seem to be, roughly, of the correct order), and using equation (A (page 569)), it will be seen, if the experiments here referred to and the assumptions are substantially correct, that doubling or even multiplying by several fold the present amount of carbon dioxide, which would leave the absorption of solar radiation practically unchanged, and increase the absorption of terrestrial radiation at most to only 14 per cent, could increase the intensity of the radiation received at the surface of the earth about one-half of 1 per cent, and, therefore, the average temperature by no more than about 1.3 C.

Similarly, reducing the carbon dioxide by one-half could decrease the temperature by no more than approximately the same amount, 1.3 C.

Physics Of The Air – 1929 – McGraw-Hill Book Company
W J Humphreys
https://archive.org/details/physicsoftheairs032485mbp

In 1942 Walter M. Elsasser refined the science of heat transfer by infrared radiation in the lower atmosphere [although this fact is omitted from his biography in Wikipedia] and his statements were subsequently confirmed in 1995 [as documented later in this posting].

Firstly, he revealed the radiative role of ozone was “negligible” in the lower atmosphere.

Page 21
Ozone has also absorption bands in the infrared region, but its influence upon infrared radiative transfer in the lower atmosphere is negligible, while it may become of some importance in the stratosphere.

In the present monograph we deal mainly with heat transfer in the lower atmosphere and we may disregard ozone as a radiator.

Heat transfer by infrared radiation in the atmosphere – 1942 – Harvard University
Walter M. Elsasser
https://archive.org/details/ElsasserFull1942

Secondly, he revealed that the narrow absorption band of carbon dioxide did not contribute to the radiative balance in the lower atmosphere.

Page 21
It is found that the absorption of carbon dioxide is concentrated chiefly in one rather narrow region of the spectrum where it is very intense.

Page 22
It may be noted that since the flux in the carbon dioxide band is equal, at any level, to a definite fraction of the black body radiation corresponding to the temperature of that level both in upward and downward direction, the resultant flux of carbon dioxide radiation vanishes in the approximation of the chart.

This is a fair approximation to the truth in the lower atmosphere (for the upper atmosphere see Section 12).

Heat transfer by infrared radiation in the atmosphere – 1942 – Harvard University
Walter M. Elsasser
https://archive.org/details/ElsasserFull1942

Reflecting the cyclical nature of Earth’s climate the question of CO2 arose again in the 1970s.

Carbon Dioxide and Aerosols
The relative roles of changing carbon dioxide and particle loading as factors in climatic change have been assessed by Mitchell (1973a, 1973b), who noted that these variable atmospheric constituents are not necessarily external parameters of the climatic system but may also be internal variables; for example, the changing capacity of the surface layers of the oceans to absorb C02, the variable atmospheric loading of wind-blown dust, and the interaction of C02 with the biosphere.

The atmospheric C02 concentrations recorded at Mauna Loa, Hawaii (and other locations) show a steady increase in the annual average, amounting to about a 4 percent rise in total C02 between 1958 and 1972 (Keeling et ai, 1974).

The present-day C02 excess (relative to the year 1850) is estimated at 13 percent.

A comparison with estimates of the fossil C02 input to the atmosphere from human activities indicates that between 50 and 75 percent of the latter has stayed in the atmosphere, with the remainder entering the ocean and the biosphere.

The C02 excess is conservatively projected to increase to 15 percent by 1980, to 22 percent by 1990, and to 32 percent by 2000 a.d.

Again, the science of the day downplayed the importance of CO2 and estimated its impact to be “about 0.3 °C per 10 percent change of C02” and noted that CO2 appeared “capable of accounting for only a fraction of the observed warming of the earth between 1880 and 1940”.

The corresponding changes of mean atmospheric temperature due to C02 [as calculated by Manabe (1971) on the assumption of constant relative humidity and fixed cloudiness] are about 0.3 °C per 10 percent change of C02 and appear capable of accounting for only a fraction of the observed warming of the earth between 1880 and 1940.

They could, however, conceivably aggregate to a further warming of about 0.5 °C between now and the end of the century.

The total global atmospheric loading by small particles (those less than 5 um in diameter) is less well monitored than is C02 content but is estimated to be at present about 4xl0 7 tons, of which perhaps as much as 1 x 10 7 tons is derived both directly and indirectly from human activities.

If the anthropogenic fraction should grow in the future at the not unrealistic rate of 4 percent per year, the total particulate loading of the atmosphere could increase about 60 percent above its present-day level by the end of this century.

The present-day anthropogenic particulate loading is estimated to exceed the average stratospheric loading by volcanic dust during the past 120 years but to equal only perhaps one fifth of the stratospheric loading that followed the 1883 eruption of Krakatoa.

The impact of such particle loading on the mean atmospheric temperature cannot be reliably determined from present information.

Recent studies indicate that the role of atmospheric aerosols in the heat budget depends critically on the aerosols’ absorptivity, as well as on their scattering properties and vertical distribution.

The net thermal impact of aerosols on the lower atmosphere (below cloud level) probably depends on the evaporable water content of the surface in addition to the surface albedo.

Aerosols may also affect the structure and distribution of clouds and thereby produce effects that are more important than their direct radiative interaction (Hobbs et al., 1914; Mitchell, 1974).

Understanding Climate Change – 1975 – National Academy of Sciences
https://archive.org/details/understandingcli00unit

Given the worries about a cooling climate [at that time] the National Academy of Sciences concluded that “the widely differing atmospheric residence times of the two pollutants means that the particulate effect will grow in importance relative to that of C02”.

Of the two forms of pollution, the carbon dioxide increase is probably the more influential at the present time in changing temperatures near the earth’s surface (Mitchell, 1973a).

If both the C02 and particulate inputs to the atmosphere grow at equal rates in the future, the widely differing atmospheric residence times of the two pollutants means that the particulate effect will grow in importance relative to that of C02.

Understanding Climate Change – 1975 – National Academy of Sciences
https://archive.org/details/understandingcli00unit

The National Academy of Sciences also included a diagram of the Earth’s energy budget that clearly labelled the secondary role played by CO2 in the atmosphere.

The mean annual radiation and heat balance of the atmosphere, relative to 100 units of incoming solar radiation, based on satellite measurements and conventional observations.

Understanding Climate Change – 1975 – National Academy of Sciences
https://archive.org/details/understandingcli00unit

Then, unsurprisingly, the Earth’s energy budget remained constant for the next thirty odd years.

Atlas of Satellite Observations Related to Global Change – 1993
Cambridge University Press
Edited by Robert J. Gurney, James L. Foster, and Claire L. Parkinson

However, in the new century, the scaremongering post-normal scientists [who believe in Catastrophic Anthropogenic Global Warming] simply ignored the scientific method and invented the bogus concept of back radiation which they incorporated into their energy budgets.

Global climate, the energy balance and the hydrologic cycle
http://www.colorado.edu/geography/class_homepages/geog_3511_s13/notes/Notes_2.pdf

Sadly, this bogus post-normal back radiation science is still mainstream in 2013.

http://en.wikipedia.org/wiki/Earth%27s_energy_budget

However, some really good science can still be found on the internet.

Stratospheric cooling rates:

The picture shows how water, cabon dioxide and ozone contribute to longwave cooling in the stratosphere.

Colours from blue through red, yellow and to green show increasing cooling, grey areas show warming of the stratosphere.

The tropopause is shown as dotted line (the troposphere below and the stratosphere above).

For CO2 it is obvious that there is no cooling in the troposphere, but a strong cooling effect in the stratosphere.

Ozone, on the other hand, cools the upper stratosphere but warms the lower stratosphere.

http://www.atmosphere.mpg.de/enid/20c.html

Thankfully, there are some excellent bloggers reporting upon the really good science.

The overall message of this graph is just that in the troposphere, water is everything and CO2 is nothing.

We can also add to this graph that convection and evaporation / condensation are major processes in the troposphere and this radiative model isn’t really all that important for surface cooling at all.

In the stratosphere we see some cooling from water vapor, so, little as there is up there, it still does something.

However, THE largest blobs of cooling color come from CO2 and ozone.

Adding CO2 to the atmosphere causes more radiative heat loss from just those parts of the atmosphere that do radiative heat loss, and does nearly nothing in that part of the atmosphere dominated by convection and evaporation / precipitation.

Warming of the surface of the earth increases convection, evaporation, and water transport, and deposits that water and heat higher in the sky; so will dump more heat into the stratosphere (and perhaps more water vapor too … enhancing that water radiative part).

In short, the system is dynamic and has a convection driven lower layer, with a radiative driven upper layer.

More CO2 means more radiative heat loss, not less.

THAT is why the stratosphere has been cooling (though the upper atmosphere has dropped more on the loss of UV in the solar funk.)

Tropopause Rules

In short: The very existence of a troposphere makes the whole CO2 driven radiative IR model daft.

All that tropospheric CO2 can only close an already closed radiative window in the troposphere and contribute to the convection that is already dominant.

BTW, in deep winter with a strong polar vortex, the tropopause can reach ground level near the poles (especially the South Pole).

In that context, then, it can enhance the radiative heat dump to space.

But warming? In any mid-latitudes especially? Not a chance.

Ignore the gasses and IR / radiative story telling.

Look at the convection, mass flow, tides and ocean cold water mixing, along with solar UV shifts and how the atmosphere moves around if you would hope to know what really happens.

Arguing over CO2 and “down welling” IR is just arguing about how many Angels fit on pinheads.
…
“Warmers” think in a static scored air model.

It sits still, in constant height layers, and only radiation moves thermal energy in, and out, of the air.

In the real world, it’s a highly dynamic scored air mass, both vertical and horizontal.

Water moving by the kiloton and falling as snow and rain.

You can’t get a correct dynamic answer from a static model.

Static vs Dynamic scored air