11/13/19, rev 3/9/22,9/15/22
Water Vapor vs CO2 for Planet Warming
Dan Pangburn, P.E. (ret), MSME, ASME life member
During at least the time period when water vapor (WV) and carbon dioxide (CO2) have
been accurately measured worldwide, 1988-now, and apparently for centuries, WV
increase has been responsible for the human contribution to Global Warming with no
significant net contribution from CO2 or any other greenhouse gases.
A useful insight to the influence of WV on planet warming can be obtained from
understanding why cloudless nights cool faster and farther when absolute water vapor
content of the atmosphere is lower; especially when there is no dew or frost. This simple
observation demonstrates that water vapor is infrared electromagnetic radiation (IR)
active which makes it a so-called greenhouse gas (ghg), thermalization takes place (ghg
molecules absorbing radiant heat from the surface or other ghg and sharing the absorbed
energy with surrounding molecules), and that the misleadingly named greenhouse effect
(GHE) exists i.e. the planet surface is warmer with the presence of WV than it would be
The words ‘water vapor’ can be misinterpreted. WV is a transparent gas. If something is
visible, like steam or a cloud, it is not WV but is condensed liquid water droplets or tiny
bits of ice.
The term ‘vapor pressure’ has different meanings in different disciplines. In meteorology
it means the partial pressure of WV in the atmosphere. In most other disciplines and
general use, it means the pressure developed by the liquid as a result of its impetus to
change phase and become a gas. This impetus depends only on the temperature of the
liquid water. It is unambiguously called saturation vapor pressure. In this document, the
saturation vapor pressure is sometimes referred to simply as vapor pressure (VP). The
pressure of WV in the atmosphere might be identified as its partial pressure.
Another difference in term usage is the meaning of the word ‘feedback’. In engineering it
usually refers to feedback factor, a dimensionless number which is the ratio minus 1 of
response with feedback to the response if there were no feedback. In most science
disciplines it refers to the magnitude of the response to a forcing which contributes to the
cause of the forcing. In Climate Science it is measured in W/m2.
1. Atmospheric structure
At a scale of the size of atoms the atmosphere consists of spinning and vibrating gas
molecules, with empty space between them, bouncing elastically off surfaces and each
other. Activity of all of the gas molecules determines properties which can be measured
such as temperature and pressure. Only certain gas molecules significantly contribute to
radiation heat transfer. These are IR active in the wavelength range of earth temperatures,
are misleadingly called greenhouse gasses (ghg) and include CO2 and WV. The radiation
energy travels from ghg molecule to ghg molecule (or between surface and ghg) at the
speed of light but dwells in each molecule for about a second making the molecule
warmer. The increased cumulative dwell time from increased WV molecules is what
causes the increased Greenhouse Effect (GHE)
Approximately 99% of dry atmospheric molecules are non-ghg; nearly all nitrogen and
oxygen with about 1% argon. Near the surface, they are substantially warmed by
thermalization of the earth-source thermal radiation energy absorbed by the ghg
molecules and, at higher altitudes (starting a few meters or less above the surface), cooled
by pressure decline and reverse-thermalization back to the ghg molecules. Increasingly
with altitude, because of decline of the population of WV molecules, lower pressure, and
wider spacing between ghg molecules, outward directed radiation from WV molecules
can make it all the way to space.
All molecule species are fairly well mixed throughout the atmosphere with the exception
of WV. WV molecule population declines with altitude from average of about 10,000
ppmv (parts per million by volume) at sea level to, because of the low temperature (~ -50
°C, saturation vapor pressure of ice 3.94 Pa  and total pressure at 12 km of 19,400
Pa), to a maximum of about 3.94/19,400 = 0.000203 = 203 ppmv at the tropopause. The
10,000 ppmv (1%) average increases to about 4% in the tropics.
The tropopause altitude averages about 12 km (39,370 ft) with up to 16 km or so at the
equator. In addition to the population decline of WV molecules due to temperature
decline, is the decline due to average pressure decline of 19.4/101.3 = 0.19 from a sea
level pressure of 101.3 kPa. The combination results in an overall average WV molecule
population decline up to the tropopause of about 10,000/203 * 101.3/19.4 = 257 to 1.
Thermalization and/or reverse-thermalization occur continuously throughout the
atmosphere. The combination of thermalization and the steep gradient of WV molecules
causes much of the energy absorbed by CO2 to be shared with (redirected to) WV
molecules which radiate it to space. This energy transfer and WV molecule population
decline of about 257 to one with altitude produce the notch and ‘hash’ in Top-of-
Atmosphere (TOA) graphs of radiation flux vs wavenumber/cm. A typical example of
such a graph, showing 18 W/m^2 being redirected to WV, is at Figure 1.
A much more extensive description of thermalization is at Section 4 of .
Figure 1: Thermal radiation from below assessed from top-of-atmosphere. Lower
wavenumber photons are lower energy. (Original graph is from NASA )
3. Relative influence of CO2 and WV on climate
Hitran  using Quantum Mechanics calculates, besides many other things, the relative
absorb/emit intensity of water vapor molecules vs CO2 molecules. Comparison at zero
altitude is shown in Figure 2. Comparison by the ratio of the summation of the
multiplication products intensity times wavenumber for each transition (vertical lines on
the graph) for each molecule species is (Σ Ii * wni)WV / (Σ Ij * wnj)CO2 ≈ 1520/46 = 33. On
average at ground level, according to the comparatively low populations used by Hitran,
WV molecules outnumber CO2 molecules by about 8,000/330 ≈ 24 to one. After
accounting for molecule count, each WV molecule is still 33/24 ≈ 1.37 times more
effective at warming (absorb/emit of thermal radiation) than a CO2 molecule.
Figure 2: At zero altitude, CO2 absorb/emit is barely discernable compared to WV.
The relative effectiveness of the increases of WV and CO2 over the last 30 years is
calculated as follows:
CO2 increase in 3 decades , 1988 to 2018: 407 - 348 = 59 ppmv
Average global water vapor increase trend from Figure 5, which is a graph of NASA/RSS
TPW data, is 0.04268/28.9 * 100 * 10 = 1.47 % per decade.
From Figure 3, at 30 degrees latitude (area to pole = area to equator) average global WV
≈ 10,000 ppmv. WV increase in 3 decades = .0147 * 10,000 * 3 = 441 ppmv.
Figure 3: Water vapor declines with latitude and rapidly with altitude.  (original
Therefore, WV increase has been 441/59 * 1.37 ≈ 10 times more effective at increasing
ground level temperature than CO2 increase 1988-2018. (Much of the world human
population has been falsely indoctrinated)
A similar assessment made at an altitude of 5 km gives the following results:
WV transition line sum of products = 187.63
CO2 transition line sum of products = 25.47
Ratio of transition line sum products = 187.63/25.47 = 7.37
WV molecules at 5 km per Hitran atmosphere browser, std atm = 1420 ppmv
CO2 molecules at 5 km per Hitran atmosphere browser, std atm = 330 ppmv
WV molecules outnumber CO2 molecules 1420/330 = 4.30 to one.
At 5 km, after accounting for molecule count, each WV molecule is 7.37/4.30 = 1.71
times more effective than a CO2 molecule at thermalization.
WV increase at 5 km in 3 decades = 1420/8000 * 441 = 78.28 ppmv.
At 5 km WV increase has been 78.28/59 * 1.71 = 2.27 times more effective at
absorb/emit than CO2 increase 1988-2018.
More importantly, the outward directed emission of WV below wavenumber 600 and
from below the tropopause makes it all the way to space while outward directed emission
from CO2 molecules in the wavenumber range 600-740 is absorbed by CO2 molecules
above. Nearly all of this energy absorbed by CO2 is redirected via thermalization to the
Well above the tropopause, radiation emitted from molecules there to space is primarily
from CO2 molecules (indicated in Figure 1 by the spike at wavenumber 667). If you
ignore the increase in water vapor (big mistake), near the surface, WV averages about
10,000 ppmv. The increase in absorbers at ground level since 1900 is then about
10,410/10,295 ≈ 1%. WV above the tropopause is limited to about 149 ppmv because of
the low temperature (~ -50 °C) while the CO2 fraction remains essentially constant with
altitude at (in 2019) about 410 ppmv; up from about 295 ppmv in 1900. The increase in
emitters to space at high altitude (~> 20 km, 0.055 atm), and accounting for the lower
atmospheric pressure, is (410 + 149)/(295 + 149) * 0.055 ≈ 0.069 = 6.9%. This explains
why CO2 increase does not cause significant warming (except near the poles). The result
being that Climate Sensitivity (the temperature increase resulting from doubling the CO2
level) is not significantly different from zero.
The exception at the poles is because it’s cold there at ground level so WV molecule
count is already low. Therefore, transfer of energy to WV molecules which radiate it to
space is negligible.
4. Water vapor increase is a cause and also a result of warming
WV increase is a cause of warming (average global temperature increasing) because it is
a ghg. Part of WV increase is a result of surface water warming because its saturation
vapor pressure increases with temperature. The saturation vapor pressure increase causes
an increase in the rate of WV molecules being forced into the atmosphere (when the
atmosphere at ground level is less than saturated with WV which is usually the case). An
additional source of WV increase is human activity, especially irrigation. This is
discussed further in Section 6.
In the atmosphere, condensed water can exist as water, ice or super-cooled water 
(super-cooled water is liquid water below 0.0 °C). Accurate numerical values for
saturation vapor pressure of liquid water  and ice  are graphed in Figure 4.
Saturation vapor pressure for super-cooled water can be calculated using the Bolton
equation . The Bolton equation for saturation vapor pressure in kPa vs temperature in
p = 0.6112 * e^(17.67 * T / (T+243.5)) (1)
As shown in Figure 4, saturation vapor pressure increases progressively with
temperature. Of interest is the % increase in saturation vapor pressure per degree increase
in temperature. This is readily calculated from the numerical data for both liquid water
and ice from:
1/1 increase/Tave = (pj – p(j-1)/(Tj – T(j-1))/Tave (2)
1/1 = %/100
j and (j – 1) are adjacent values in the table
Tave = average temperature of the adjacent values.
The same thing for super-cooled water is obtained using the first derivative of the Bolton
equation which is
dp/dT = p * 17.67 * 243.5/(T+243.5)^2 (3).
This, divided by p to get the 1/1 value curve, is shown in the bottom graph at Fig. 4.
Saturation vapor pressure depends ONLY on the temperature of the ice or liquid water.
The 1/1 change in saturation vapor pressure per Celsius degree for water, ice and super-
cooled water are shown in the lower graph of Figure 4.
Figure 4: Saturation vapor pressure of ice &water and fractional rate of change per
C degree change vs temperature.
The atmospheric temperature decreases with altitude so the accommodation for WV
increases with altitude to about 12%/C° at the tropopause (°C is a temperature, C° is a
temperature difference). This can result in the perhaps counterintuitive condition that as
surface temperature increases, WV (specific humidity) increases but accommodation for
WV in the atmosphere increases even more, so relative humidity decreases.
Based on ocean temperatures from , the area-weighted change in saturation vapor
pressure per C degree at sea level is about 0.0633 / C°. The amount of compounding is
unknown but cannot be greater than 0.0633+0.0633^2+0.0633^3+… = 0.0676/C°. It is
conservatively estimated to be about 0.067/C° = 6.7%/C°
5. Measured water vapor increase
The accelerated increase in WV which is expected from the surge in irrigation has also
been measured. Average measured global atmospheric water vapor (total from surface to
TOA) over the years is provided here at Figure 5.
Clear sky water vapor measurements over the non-ice-covered oceans in the form of total
precipitable water (TPW) have been made since Jan 1988 by Remote Sensing Systems
(NASA/RSS) . A graph of this measured ‘global’ average anomaly data, with a
reference value of 28.73 added , is shown in the left graph of Figure 5. This data is
extrapolated earlier using CO2 level as a proxy, with the expression kg/m^2 TPW =
4.5118 * ppmvCO2^0.31286. The result is the right-hand graph of Figure 5 which shows
approximately 7% increase 1960-2005.
Figure 5: Average clear air Total Precipitable Water over all non-ice-covered
oceans as measured by NASA/RSS using satellite based instrumentation and with
extrapolation by me. (Left graph, starting Jan 1988, is by month, right graph is by
year average.). Estimated near future minimum is the average since mid-2016.
Estimated near future maximum is the slope of the recent monthly trend.
6. World Sources of Increased Water Vapor
Irrigation, industrialization, and, increasing population have been causing the rise in
atmospheric WV above that from feedback due to liquid water temperature increase. A
survey of available on-line literature provides direct and indirect quantification of
significant global sources of the extra increase.
Transportation fuel, linearly interpolated to 2017, amounts to 113E15 BTU/y . Energy
content of a typical liquid fuel is 115,000 BTU/gal . Liquid fuels weigh about 6.073 lb/
gal = 2.75 kg/gal. Therefore transportation fuels amount to
113E15 * 2.75/115000 = 2.7E12 kg fuel/y (a)
About 1.42 kg of WV is produced for each kg of liquid fuel  so the amount of WV
produced by transportation is
2.7E12 * 1.42 = 3.8E12 kg WV/y (b)
World electricity generation is now about 25,000 TWH/y . At an average efficiency of
50% and ignoring non-thermal sources this requires a thermal input of 50,000 TWH/yr.
Fuel source fractions of energy  in 2017 are approximately 0.38 coal, 0.36 natural gas
and 0.26 non fossil fuel.
Coal combustion produces about 0.4 kg WV/kg coal . Energy content of bituminous
coal is about 8200Wh/kg . The amount of WV resulting from burning coal to
generate electricity is then
50E15 * 0.38 * 0.4/8200 = 0.93E12 kg WV/y (c)
The amount of WV produced by natural gas (nearly all methane, CH4) is readily
calculated from the dominant chemical reaction
CH4 + 2O2 => CO2 + 2H2O (d)
Where a mole of methane weighs about 16 g and the two moles of WV weigh about 18 g
Natural gas energy content is about 15,400 Wh/kg . The amount of WV resulting
from burning natural gas to generate electricity is then
50E15 * 0.36 *36/16/15400 = 2.6E12 kg WV/y (e)
The total WV from all fossil fuel used to generate electricity is then
0.9E12 + 2.6E12 = 3.5E12 kg WV/y (f)
Waste energy during electricity generation can be approximately accounted for by
evaporation of water in cooling towers, etc. At 50% efficiency the waste energy is the
same as the energy in the electricity produced, 25,000 TWH/yr = 25E12 kWh/y.
Latent heat of water = 2257 kJ/kg = 0.627 kWh/kg = 1.594 kg/kWh.
The amount of WV from waste heat (cooling tower, etc.) during electricity generation is
25E12 * 1.594 = 39.8E12 kg WV/y (g)
Irrigation is by far the largest source of WV. The increase in irrigation is indicated by the
increase in withdrawal for agriculture as shown in Figure 6 .
Figure 6: Global water withdrawal includes both ground water and surface water
The total agricultural area equipped for irrigation in 2012 was 324E10 m2 . Estimate
80% were actually being irrigated. Estimating an increase of 2% to 2017, the total area
being irrigated is now about
324E10 * 0.8 * 1.02 = 266E10 m2 (h)
This is more than 4 times the area of France and is probably warmer than the tropics.
Total annual fresh water withdrawal (both ground and surface) is now 3,986 km3 =
3.986E15 kg/y . Of this, about 70% is for agricultural use . This works out to
3.986E15 * 0.7/266E10 = 1052 kg/m2/y ≈ 1 m/y (i)
which appears reasonable because average rainfall for the planet is about 1 m/y.
Evapotranspiration, WV from plants and landscape, is discussed in the ‘thematic
discussion’ of Aquastat . From there, the amount of precipitation on land is 110,000
km3 /y of which the fraction evapotranspirated is 0.56 + 0.05 = 0.61. Given the planet
surface area of 510.1E6 km2, and land fraction of 0.29 this results in the equivalent liquid
depth of the total amount of water leaving the surface as WV as
110,000 * 0.61/0.29/510.1E6 = 0.00045 km/y = 0.45 m/y (j)
Water weighs 1000 kg/m3 so evapotranspiration amounts to 450 kg/m2 /y.
Worldwide about 86% of irrigated area is flood irrigated . To simplify calculation,
assume all irrigation is flood irrigation approximated as furrow type . Optimum
frequency is to flood the furrows about every 10 days . Thus about half the area is
covered by water 10% of the time where evaporation from the water is about one meter
per year  and the rest of the time, the additional evaporation is assumed to be
according to the calculated evapotranspiration. Evapotranspiration prior to irrigation must
have been low or irrigation would not be done. Evapotranspiration with irrigation, to be
cost effective, is most likely to be much more than calculated. These two uncertainties are
assumed to approximately cancel each other. A further assumption is that, on average,
irrigation is applied for about 1/3 year. The total amount of WV resulting from irrigation
[(0.1 * (1 + 0.45)/2 + 0.9 * 0.45) * 266E10]/3 = 42.3E10 m3/y= 42.3E13 kg/y (k)
These calculations are summarized in Table 1
Water vapor source E13 kg/y %
Irrigation 42.3 90.0 %
Transportation fuel 0.4 0.8 %
Fossil fuel for electricity
0.3 0.7 %
Cooling towers, etc. for
Total 47.0 100 %
Table 1: Summary of contributions to atmospheric water vapor.
WV increase above that due to feedback from liquid water temperature increase results
about 90 % from irrigation. WV added by irrigation might be particularly influential
because it is added at locations where natural WV is low and because the liquid water is
shallow, it is quickly and substantially warmed by the sun.
The area of the oceans, much of it quite cold, produced the WV responsible for the basic
GHE temperature increase of 33 K. The added WV, mostly from irrigation in previously
warm dry areas, has contributed an additional approximately 0.8 K  of the total
average global temperature increase since 1700. Ref  identifies the three contributing
factors, the data sources, and the algorithm which calculates the temperatures which
match measured average global temperatures 96+% 1895-now (thru 2020).
Given the earth area of 510E12 m^2 and average annual precipitation of about a meter or
1000 kg/m^2 the increased water use, mostly for irrigation, results in 42.3E13/5.1E17 =
0.0008 = 0.08 % equivalent increase in global precipitation.
7. Comparison of measured WV with WV increase calculated from feedback over a
long time period.
Some people have asserted that WV content increases with air temperature. That would
be true if the air was all continuously at saturation. Of course it is not. The driving factor
for WV increase from temperature increase is the temperature increase of the liquid water
source. Increase of air temperature does add accommodation for the added WV. The NET
driving factor is the vapor pressure deficit which is the difference between the saturation
vapor pressure of the liquid surface water and the partial pressure of WV in the
As described in Section 4, as the temperature of liquid surface water increases, its vapor
pressure increases which, if it’s not already saturated, forces more WV molecules into the
atmosphere. This contributes to a net feedback from all factors which caused the
temperature to increase. A conservative value for WV increase (actual WV increase from
feedback will be less than so calculated) was estimated in Sect 4 from available measured
data to be 6.7% = 0.067 1/1. The large effective thermal capacitance of the planet is the
main contributor to the conservatism. The temperature rise is in response to the time-
integral of the forcing so it will lag the feedback forcing.
The file for calculated change in WV is generated in EXCEL where each row contains:
WVn = WV(n-1) + (Tn – T(n-1))* R * (WV(n-1) + F)
WVn = calculated WV in month n, kg/m^2
Tn = temperature anomaly in month n, C°
R = effective rate of WV increase resulting from feedback of temperature increase, 0.067/
C° (= 6.7 %/C°)
F = added to avoid circular reference of (WV(n-1)+WVn)/2
For HadCRUT5  as of Dec 2021, F = 0.029835/24 = 0.00124 kg/m^2/month. Slope at
F = 0 is 0.0298342. Effect over 34 yr = (0.0298355 - 0.0298342)*34 = 0.000044 kg/m^2
The starting calculated WV is adjusted to make the starting trends the same.
The results of this algorithm are shown in Figure 7 along with the actual measured WV
anomaly measured and reported by NASA/RSS  (plus 28.73). The measured WV is
about 40.4% steeper than the calculated trend using HadCRUT5, Jan 1988 – Dec. 2021
temperature trend and 6.7%/K.
Figure 7: Measured WV and calculated WV based on HadCRUT5 reported average
global temperatures and compounded feedback.
The GCMs calculate the WV within the models with the result that relative humidity is
approximately constant. The linear trends assuming three different values for average
relative humidity remaining constant with increasing air temperature are included on
Figure 7.1: Same as Fig. 7 but with trends based on constant relative humidity
The observation that the actual measured trend is steeper than calculated trends
demonstrates that, on the long term, measured WV is increasing faster than possible from
just temperature increase of the liquid water (feedback). The steepest slope calculated for
the constant RH cases is (29.36 – 28.242)/34 = 0.0329 kg/m^2/y. The measured trend is
then 0.0419/0.0329 = 1.27 or about 27% steeper than the estimated trend calculated
An even more basic consideration is that determining the influence of increased WV
from just feedback from temperature increase is too low because it does not include the
WV added by human activity. The only valid consideration for the influence of WV
increase is to use the measured WV increase.
A corroboration of the long-term temperature trend is as follows: Assume that at the
beginning of the warm up the temperature increase was caused by something else. Then
the WV increase can be calculated from that temperature increase using the saturation
vapor pressure vs temperature for water and the assumption that % increase in WV = %
increase in saturation vapor pressure. But the WV has increased more than that so there
has to be an additional source of WV. The additional source of WV (about 90% from
irrigation) is the something else that produced the initial warming.
8. Over a short time period, water temperature drives WV.
Surface water temperature fluctuates as shown in an animation . A particularly
dominant fluctuation is in the equatorial Pacific and is tracked and reported weekly as el
Nino. Fluctuations in el Nino affect short term global average WV and average global
temperature as shown in Figure 8.
Figure 8: On the short term, local water temperature fluctuations drive global WV
and average global temperature.
9. Influence of WV increase on HadCRUT4 average global temperature.
Figure 9 is a plot of the measured WV vs measured HadCRUT4 data . It shows the
short term scatter as well as the long term trend of the influence of WV on average global
Figure 9: Scatter graph of WV vs HadCRUT4 measured data.
This provides fertile ground for those motivated to mislead to cherry-pick periods where
the increasing side of fluctuations drives both WV and outgoing-longwave-radiation up.
10. Energy Redirection
Figure 10 shows TOA radiation flux intensity vs wavenumber as calculated by Modtran
. This calculated radiation flux profile has been corroborated by satellite
measurements . Superimposed on the graph are plots of black body radiation flux at
specific temperatures. Black body radiation imposes an upper limit on radiation intensity
at characteristic wavenumbers of each ghg.
Figure 10: Typical TOA radiant emission
Standard atmosphere tables show temperature vs altitude so the bb radiation curves are
also altitude curves. The curves are very nearly equally spaced (the lapse rate) up to the
tropopause. From this it is seen for example that all radiation emitted in the range 500-
600/cm is from between the altitudes 2 – 6 km and that the outward directed radiation in
this range makes it all the way to space.
Essentially all of this radiation comes from WV molecules. The result is energy absorbed
by CO2 molecules at this altitude range is shared with surrounding molecules via gaseous
conduction and the fraction radiated outward by WV molecules makes it all the way to
space. Effectively radiation energy absorbed by CO2 is redirected to WV where it is
radiated to space.
This process applies to all radiation absorbed by CO2 molecules up to the tropopause and
accounts for the energy missing from below the tropopause in the wavenumber range
Humanity’s contribution to planet warming is from increased atmospheric water vapor
resulting nearly all from increased irrigation. The increased CO2 has negligible effect on
warming. Climate Sensitivity, the temperature increase from doubling CO2, is not
significantly different from zero.
1. NASA/GISS TOA graph source
2. HITRAN data base calculator
3. Mauna Loa CO2: ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_mm_mlo.txt
4. Water vapor vs altitude http://homeclimateanalysis.blogspot.com/2010/01/earth-
5. NASA/RSS TPW http://www.remss.com/measurements/atmospheric-water-vapor
(they only report data which includes the latest month available, 201910 means thru
6. Transportation fuel https://www.eia.gov/outlooks/ieo/pdf/transportation.pdf
7. Fuel properties https://en.wikipedia.org/wiki/Gasoline
8. World electricity generation https://yearbook.enerdata.net/electricity/world-electricity-
9. Fuel sources for electricity generation
10. WV from coal combustion http://energyeducation.ca/encyclopedia/Water_vapour
11. Energy content of bituminous coal https://en.wikipedia.org/wiki/Energy_density
12. Global water withdrawal http://www.fao.org/nr/water/aquastat/water_use/index.stm
13. Irrigated agricultural area
14. Annual fresh water withdrawal
15. 70% of withdrawal is for agriculture
16. Surface irrigation https://water.usgs.gov/edu/irfurrow.html
17. Frequency of furrow irrigation https://naldc.nal.usda.gov/download/54786/PDF
18. Pond evaporation rate http://www.nws.noaa.gov/oh/hdsc/Technical_papers/TP13.pdf
19. Climate change drivers http://globalclimatedrivers2.blogspot.com
20. Surface irrigation 86%: http://www.fao.org/3/I9253EN/i9253en.pdf
21. Ocean surface temperature animation https://www.youtube.com/watch?
22. Modtran: http://forecast.uchicago.edu/Projects/modtran.orig.html
23. Modtran comparison with measured:
24. Atmospheric absorption of water vapor is logarithmic:
25. Bolton equation for water saturation p T https://glossary.ametsoc.org/wiki/Clausius-
26. Ice and mixed phase clouds:
27. Wexler, vapor pressure of water:
28. Wexler, thermodynamic calculations for the vapor pressure of ice:
29. Ocean temperatures: https://rwu.pressbooks.pub/webboceanography/chapter/6-2-
30. HadCRUT4 data:
31. HadCRUT5 data: