Describes all important observations of climate change and assesses the possible effects of increased CO2, human activity energy consumption, and large-scale crop irrigation.

1. Climate Change – Carbon Dioxide or Crop Irrigation?
Keith Shotbolt
University of Birmingham. Independent Energy Consultant, Gerrards Cross, UK.
Correspondence to: keith.shotbolt@hotmail.co.uk 16/04/2021.
Abstract. Observations of rising temperatures and more extreme weather phenomena have raised concern
about climate change. Over the last 50 years, most attention has been paid to the possibility that rising
concentration of atmospheric carbon dioxide is the major cause of warming by a concept named ‘radiative
forcing’. Since 1997, Climatologists have acknowledged that water vapour plays a more significant part than
CO2 towards atmospheric warming. However, they have considered that as water vapour has an average
ten-day life following evaporation, and the quantity generated by the human activity of crop irrigation is
small relative to the naturally-occurring quantity, it can be ignored. Most Climatologist reports have not
considered that crop irrigation is a late Spring and Summer activity, with most of it located on Northern
Hemisphere land that is far from the influence of the oceans. Little attention has been paid to the fact that
evapotranspiration of water vapour from crops absorbs a large quantity of the Sun’s energy as latent heat.
The unseen vapour is transferred to cooler latitudes by atmospheric circulation winds. It condenses to form
clouds, releases its latent heat, and falls as rain. This paper presents the basic results of NASA/NSIDC satellite
observations of polar sea ice extents, NASA’s publication of world temperature changes, and reports of
Southern Hemisphere glacier behaviour. It then assesses whether: (a) increased atmospheric CO2
concentration to 4.12 parts in 10,000 by volume, or (b) crop irrigation using at least 2,600 billion tonnes of
water, best explains the observations.
1. Climate Change and Possible Cause
There have been many observations of Earth’s climate showing general warming.
Figure 1. Central England Annual Temperatures (HadCET) over the years since 1721 (UK Met Office 1, 2017).
The temperature record in Figure 1 is a typical example, with the average increasing from 9o
C over the first
180-year period, and rising gradually to more than 10o
C over the last 120 years. There was no evidence of
warming before year 1900, but scientists had speculated about the influence of atmospheric gases on Earth’s
climate. One noted that after the Sun’s radiation warmed the Earth, water vapour in the atmosphere
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2. restricted radiation from the warmed surface back into space (Tyndall, 1861), and another tried to quantify
the similar property of carbon dioxide (Arrhenius 1896). In 1901, a Meteorologist noted that the atmosphere
may act, quote: “like the glass of a green-house.” This was the first historical reference to a possible
atmospheric ‘greenhouse effect’. (Ekholm 1901).
In December 1985, the United States Department of Energy, Office of Basic Energy Sciences, Carbon Dioxide
Research Division issued a 229-page report entitled: ‘Detecting the Climatic Effects of Increasing Carbon
Dioxide.’ The Preface states, quote: “Virtually all theoretical studies suggest that the increasing atmospheric
CO2 concentration will significantly increase global average temperature. However, even though the CO2
concentration has risen about 25% since the middle of the last century, such a warming is not yet clearly
identifiable in the observational record… Using different assumptions and data sets, most have found that
the record is consistent with the predictions. However, even with differences in the analyses and the simple
models that have been used, none have been able to verify a cause-and-effect relationship regarding the role
of CO2 in climate change.” The report recommends further recording of climate data and further computer-
modelling to allow prediction of future trends in the climate (MacCracken, 1985).
In June 1988, Dr James E. Hansen, Director of NASA’s Goddard Institute of Space Studies (GISS), told a
Congressional committee that it was 99 percent certain that the (observed climate) warming trend was not
a natural variation but was caused by a build-up of carbon dioxide and other artificial gases in the atmosphere
(New York Times 1988). My understanding is that NASA GISS received research-funding from the DoE Carbon
Dioxide Research Division, and that the computer-modelling was based on the questionable concept of
‘radiative-forcing’, see comment by Gerlich and Tscheuschner in the next Section.
Radiant energy arriving from the Sun varies during the year due to the rotational axis of the Earth being tilted
23.5 degrees to the plane of its orbit, see Figure 2. Total radiant energy arriving from the Sun has been
estimated at 3,400,000 exajoules per year {Breeze, 2019]
Figure 2.
Due to the leaning angle of the Earth’s axis, its effect on radiation arriving in each hemisphere is a maximum
at the Solstices. Radiation reaching the Poles is similar in the Arctic and the Antarctic. Both Poles have
continuous sunlight for 11 weeks during their Summer. Food crops in latitudes 20 to 60 degrees are normally
sown in the Spring to Summer period to benefit from the best light and heat conditions. They are harvested

3. in late Summer to Autumn. During Winter in each hemisphere, all latitudes are tilted up to 23.5 degrees away
from their equinox, or neutral position.
Since 1988, most attention has been paid to the increase of atmospheric carbon dioxide caused by the use
of fossil fuels - coal, oil and gas (methane) - and methods to reduce emissions. Consumption of world energy
for the human activities of industry, transport, municipal and domestic uses from all fuels in 2019, including
renewable solar energy, was 583.9 exajoules. Fossil fuel contributions in exajoules were: coal 158, oil 193,
and natural gas 141, making 84% of the total. [bp company, 2020]. The energy arriving from the sun is
therefore more than 5,800 times the energy used for all human activities.
2. Descriptions of Greenhouse Gases after Year 2000
At the beginning of the 21st century, the consensus view was that, quote: “The most important of the
greenhouse gases is water vapour, but its amount in the atmosphere is not changing directly because of
human activities. The important greenhouse gases that are directly influenced by human activities are carbon
dioxide, methane, nitrous oxide, the chlorofluorocarbons (CFCs) and ozone. Carbon dioxide (CO2) has
contributed about seventy per cent of the enhanced greenhouse effect to date, methane (CH4) about
twenty-four per cent, and nitrous oxide (N2O) about six per cent.” [Houghton 2004]
IPCC Report AR4, FAQ 1.1, states: “The reason the Earth’s surface is this warm is the presence of greenhouse
gases, which act as a partial blanket for the longwave radiation coming from the surface. This blanketing is
known as the natural greenhouse effect. The most important greenhouse gases are water vapour and carbon
dioxide. The two most abundant constituents of the atmosphere – nitrogen and oxygen – have no such effect.
…. Human activities intensify the blanketing effect through the release of greenhouse gases. For instance,
the amount of carbon dioxide in the atmosphere has increased by about 35% in the industrial era, and this
increase is known to be due to human activities, primarily the combustion of fossil fuels and removal of
forests.” [AR4, IPCC 2007]
IPCC Report AR5, FAQ 8.1, states: “Water vapour is the primary greenhouse gas in the Earth’s atmosphere.
The contribution of water vapour to the natural greenhouse effect relative to that of carbon dioxide (CO2)
can be considered to be approximately two to three times greater. Additional water vapour is injected into
the atmosphere from anthropogenic activities, mostly through increased evaporation from irrigated crops,
but also through power plant cooling (e.g. fossil fuel and nuclear power station cooling towers), and
marginally through the combustion of fossil fuel. With every extra degree (Centigrade) of air temperature,
the atmosphere can retain around 7% more water vapour. ….. The typical residence time of water vapour in
the atmosphere is ten days. The flux of water vapour into the atmosphere from anthropogenic sources is
considerably less than from ‘natural’ evaporation. Therefore, it has a negligible impact on overall
concentrations, and does not contribute significantly to the long-term greenhouse effect. This is the main

4. reason why tropospheric water vapour (typically below 10 km altitude) is not considered to be an
anthropogenic gas contributing to radiative forcing.” (AR5, IPCC 2013].
A 2009 paper entitled ‘Falsification of the Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics’
by two German expert Mathematical Physicists states: “The atmospheric greenhouse effect, an idea that
many authors trace back to the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896), and
which is still supported in global climatology, describes a fictitious ‘radiative forcing’ mechanism, in which a
planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but
radiatively equilibrated to the atmospheric system….According to the second law of thermodynamics such a
planetary machine can never exist. Nevertheless, in almost all texts of global climatology, and in a widespread
secondary literature, it is taken for granted that such a mechanism is real and stands on a firm scientific
foundation.” (Gerlich and Tscheuschner, 2009).
3. Atmospheric Concentration of Carbon Dioxide
Figure 3. (Scripps Institution of Oceanography, 2020). The records show that the atmospheric content of
CO2 at the South Pole (red curve), and at Mauna Loa in Hawaii (at latitude 20 degrees North, black curve),
are similar. Results obtained at Arrival Heights, Antarctica, and Baring Head, New Zealand are very similar
(NIWA 2020). CO2 concentration has increased worldwide from 315ppm in 1960 to 410ppm (0.041%, or 4.1
parts in 10,000) in 2020.
3.1 Global Temperature and Atmospheric CO2 over Geologic Time
There has historically been much more CO2 in our atmosphere than exists today. For example, during
the Jurassic Period (200 million years ago), average CO2 concentrations were about 1800 ppm or about 4.7
times higher than today. The highest concentrations of CO2 during all of the Palaeozoic Era occurred during

5. the Cambrian Period, nearly 7000 ppm -- about 18 times higher than today. The Late Ordovician Period was
also an Ice Age while at the same time CO2 concentrations then were nearly 12 times higher than today-
- 4400 ppm. According to greenhouse theory, Earth should have been exceedingly hot. Instead, global
temperatures were no warmer than today. Clearly, other factors besides atmospheric carbon influence Earth
temperatures and global warming (Geocraft).
Figure 4. (Geocraft)
The first fish evolved over 500 million years ago, and ammonites, the largest shellfish fossils, first appeared
420 million years ago. Both species were not harmed by CO2 concentrations exceeding 3000 ppm. The sea
contains around 60 times more CO2 in solution than the quantity in the atmosphere, and any increase in
atmospheric concentration will increase phytoplankton blooms – the basic food for all marine life. Rather
than increased CO2 or ocean warming, the Queensland government says dissolved inorganic nitrogen –
originating from farm fertilisers - is linked to algal blooms, outbreaks of coral-eating starfish and coral disease
at the Great Barrier Reef (theguardian.com 2021).
CO2 is a basic requirement for photosynthesis, and horticulturalists raise the CO2 concentration to 1000 ppm
in greenhouses to improve crop yield. The UK Health and Safety Executive allows concentration up to 5000
ppm for 8-hours in a work environment, and 15,000 ppm for 15-minute exposure (hse.gov.uk).
4. Observations of World Climate
4.1 Extent of Polar Sea Ice
The National Snow and Ice Data Centre (NSIDC) and National Oceanic and Atmospheric Association (NOAA)
websites state: “The polar regions are the most sensitive areas to climate change on Earth” (NSIDC1 and
NOAA 2021).

6. The National Aeronautics and Space Administration (NASA) has been operating satellites over the polar
regions since 1979, and in 2014, the NSIDC presented graphs of September Sea Ice Extents in the Arctic and
the Antarctic over the full range of years (NSIDC2, 2014). The result for the Arctic is shown in Figure 4, and
the Antarctic in Figure 5.
Figure 5. NSIDC commented thus, quote: “Monthly Arctic September ice extent for 1979 to 2014 shows a
decline of 13.3% per decade relative to the 1981 to 2010 average.”
Figure 6. NSIDC commented thus, quote: Monthly Antarctic September ice extent for 1979 to 2014 shows an
increase of 1.3% per decade relative to the 1981 to 2010 average.
An article in the NASA Earth Observatory website commented: “You might wonder how Antarctic sea ice
could be increasing while global warming is raising the planet’s average surface temperature. It’s a question
that scientists are asking, too.” (Scott and Hansen, 2016).
Polar Sea Ice Extent for the last 3 years (and the previous 38 years) is reported by the NSIDC in their Charctic
interactive sea ice graphs, Figures 7 and 8 (NSIDC3, 2021).

7. Figure 7. Arctic Winter sea ice extents in 2019, 2020 and 2021 were slightly ahead of those recorded for 2017
and 2018. It has been known for some time that Winter sea ice has been reduced much less than Summer
sea ice. Arctic Summer extents in 2019 and 2020 were greater than the record minimum of 2012. All recent
year Arctic sea ice extent recordings are well below the 1981-2000 Median values.
Figure 8. Antarctic Summer (February) sea ice extents in 2019, 2020, and 2021 are all greater than the record
low of 2017. Present (April 2021) Antarctic sea ice extent is greater than the 1981-2000 Median value.

8. Figure 9. NSIDC data for individual years are reproduced with the full 41-year series of Arctic and Antarctic
extents on a single chart to see trends (climate4you.com, 2021). The lowest peak Antarctic Winter sea ice
extent of 17.963 million km2 was recorded in 1986, increasing to a maximum value of 20.156 million km2
in
2014. Since the reduction due to the major El Nino event of 2014-2016, it has been increasing again, reaching
18.952 million km2
in September 2020 (NSIDC3, 2021).
4.2 World Temperature Records
Figure 10. Credit: NASA’s Scientific Visualization Studio
Using data from 6,300 land and marine-based stations, NASA’s Goddard Institute for Space Studies prepared
this map showing Earth’s average global temperature from 2013 to 2017, as compared to a baseline average
from 1951 to 1980. Yellows, oranges, and reds show regions warmer than the baseline. Blues show cooler
areas. [NASA, 2018]
Note that:
• Some Northern areas have experienced warming of more than 2o
Fahrenheit (~1.1o
C).
• Large areas below 45 degrees South have cooled by 0.5 to 1o
F.

9. 4.3 Southern Hemisphere Glaciers
Glaciers near the southern blue areas of Figure 10 are those in the south of South America (Patagonia), and
on the South Island of New Zealand. The European Space Agency (ESA) has presented evidence showing that
the Pio XI Glacier in southern Chile has been advancing over the last 60 years (ESA, 2016). At a similar latitude,
the Perito Moreno Glacier located in southern Argentina is reported to be stable.
Quote: “At least 58 New Zealand glaciers advanced between 1983 and 2008, with Franz Josef Glacier at 43
degrees South (Kā Roimata o Hine Hukatere) advancing nearly continuously during this time. This was
reported to be very unusual - especially as most glaciers worldwide shrank in size due to climate warming.
The reason for glacier growth was lower temperatures, rather than increased precipitation as previously
thought.” (Victoria University of Wellington, NZ, 2017).
4.4 Assessment of These Observations
IPCC Report AR4, Chapter 1, Section 1.1 states: “Science is inherently self-correcting; incorrect or incomplete
scientific concepts ultimately do not survive repeated testing against observations of nature. Scientific
theories are ways of explaining phenomena and providing insights that can be evaluated by comparison with
physical reality. Each successful prediction adds to the weight of evidence supporting the theory, and any
unsuccessful prediction demonstrates that the underlying theory is imperfect and requires improvement or
abandonment.” (IPCC, AR4, 2007)
Observations of polar sea ice extent, world temperatures and world glaciers all show major evidence of
climate warming in the Northern Hemisphere, but no significant change in latitudes greater than 45 degrees
South. The increasing concentration of atmospheric CO2 is similar worldwide, so the expected result would
be at least some warming in extreme Southern latitudes. The hypothesis that increased CO2 concentration
is a major cause of climate warming is not proven. The observations direct attention to human activities that
might explain the reason for predominantly Northern Hemisphere warming.
5. Human Activities that may Influence Northern Hemisphere Climate
Almost 90% of the world’s human population live in the Northern Hemisphere. Activities that may influence
climate are:
• Release of energy stored in fossil and nuclear fuels.
• Increase of atmospheric water vapour due to crop irrigation.
5.1 Global Heating from Energy Usage
Notes on the Annual Meteorological Data collected at the Radcliffe Station in Oxford state: “In the 20th
century temperatures were generally higher than in the 19th century. This is thought to be an effect of the

10. Urban Heat Island (UHI). With the development of the city, more open spaces were built up. This process
produced radical changes in the nature of the surface and atmospheric properties of the city. Differences in
surface materials, drainage characteristics, sources of heat, configuration of surfaces and pollution acted to
change all aspects of the climate of the city, air temperature being affected particularly strongly. UHI effect
is the most common example of inadvertent climatic modification.” (University of Oxford, 2021)
Section 1 above notes that the energy arriving from the Sun is 5.800 times the energy consumed for all human
activities – industry, transport, municipal and domestic uses. Another source notes that the energy arriving
from the Sun is 120,000 terawatts (3,780,000 exajoules/year), which is 6,670 times that consumed for human
activities of 18 terawatts (567 exajoules/year). The author comments that this has had an ‘imperceptible’
effect on global climate to date, but does raise local temperatures in cities (Chaisson, 2008).
Energy consumption for human activities has a relatively minor influence on global climate, but its effect is
most obvious during Northern Hemisphere winter when used for heating homes and offices. The UHI effect
is very evident during winter at the town of Barrow, Alaska, at latitude 71 degrees North (Hinkel and Nelson,
2007).
5.2 Increase of Atmospheric Water Vapour
The surface of our Blue Planet is 71% covered by water.
Figure 11. Photo by NASA showing Earth’s surface dominated by water and clouds (water vapour).
The Sun causes evaporation so that the atmosphere contains up to 4% or 40,000 ppm of water vapour in the
tropical regions (that is at least 90 times the concentration of CO2) reducing to as low as 0.2% in the polar
regions (sciencing.com, 2021).
As described in Section 2 above, most climatologist literature considers water vapour to be the most
important ‘greenhouse gas’. However, AR5, IPCC Report 2013, states that it does not warrant further

11. consideration with respect to climate change, due to its “ten-day residence time and relatively low quantity
arising from anthropogenic activities.”
There are a number of reports of increased atmospheric water vapour content over northern latitudes. A
2015 paper states: “Increasing daily precipitation intensity over the years 1965 to 2000 is strongly associated
with increasing water vapor in the atmosphere over Northern Eurasia based on this study of 35 years of daily
precipitation, specific humidity, and air temperature observations at 152 stations.” (Ye, 2015).
A 2012 paper describing satellite observations of the reduction of Arctic sea ice extent states: “Positive trends
in precipitable water (i.e. total column water vapour), largest in summer and early autumn, are linked to
positive anomalies in air and sea surface temperature and negative anomalies in end-of-summer sea ice
extent.” (Serreze, 2012) These anomalies up to year 2017 are described in detail in (NSIDC4).
The possible link between increased atmospheric moisture transport from ocean evaporation and Arctic ice
melting has been investigated further, but does not mention latent heat transfer (Gimeno,2015).
5.2.1 Increased Water Vapour from Crop Irrigation
The BBC TV series entitled ‘The Life of Mammals’ broadcast its 10th
and final episode entitled ‘Food for
Thought’ on 05 February 2003. In that program, series commentator Sir David Attenborough can be seen
walking under a centre-pivot irrigation system in Arizona. Sir David advised: “With the right technology, even
the desert can yield edible crops. This (artificial) ‘rain’ has been pumped along hundreds of miles of pipes
from a far distant water supply. Every year, human beings displace the content of entire rivers in order to
water their crops. Today, over a third of the surface of the land is devoted to producing food for human
beings.” When the program was filmed in 2002, world population was 6.2 billion, which has now increased
to 7.8 billion.
Quote: “The Irrigation Juggernaut. Anyone who has flown over the American West on a clear day has
probably noticed the enormous effect that irrigated farming has had on the landscape of the country. Fields
of corn, potatoes and other crops can be seen dotting land that would otherwise be semi-desert, and the
spray from some types of irrigation systems creates perfect circles of green in these parched landscapes.”
(NY Times, 2010). Quote: “Trillions of tonnes of water have been pumped up from deep underground
reservoirs in every part of the world and then channelled into fields and pipes to keep communities fed and
watered. The water then flows into the oceans (raising sea level), but far more quickly than the ancient
aquifers are replenished by rains. Engineers and farmers have tapped hidden reserves of water to grow
grains, fruit and vegetables in the desert of Wadi As-Sirhan Basin, Saudi Arabia.” (theguardian.com, 2012).

12. Figure 12. Photo by NASA of crop circles in Kansas.
Quote: “Farmers are drawing groundwater from the giant Ogallala Aquifer faster than nature replaces it.
Every summer the U.S. Central Plains go dry, leading farmers to tap into groundwater to irrigate sorghum,
soy, cotton, wheat and corn and maintain large herds of cattle.” (theconversation.com, 2018). The crop
circles in Kansas USA in the photo above are half mile or one mile in diameter. Those in Saudi Arabia and
Russia are usually one kilometre in diameter.
Figure 13. Centre-pivot irrigation systems in Russia. (leuagro.com)
Quote “At the moment the global warming impact on Russian agriculture is currently assessed as favourable.
It has already considerably reduced the number of winters with low air temperatures threatening winter
crops. In many regions the vegetation period has increased by 5 – 10 days. The vegetation period for field
crops has been lasting longer. For instance, in Stavropol territory due to climate change the rated grain crop
capacity has increased by 30%.” (climatechangepost.com).
Figure 10. Centre-pivot irrigation systems in Russia.

13. Quote: “Meeting water requirements for future food production without compromising the water needs of
other human life-support systems is a major challenge for future freshwater management. The global total
additional water vapour flow by evapotranspiration from irrigated crops (includes evaporation from soil and
transpiration from plants) amounts to 2,600 km3
/year”, which converts to 2,600 billion tonnes per year
(Gordon et al, 2005). Approximately 90% of this quantity - 2300 billion tonnes per year - relates to the
Northern Hemisphere. This paper also advises that de-forestation has reduced water vapour flow by 3,000
km3
/year. This is not correct because: (a) de-forestation in China, USA and Europe occurred more than 100
years ago, and (b) evapotranspiration from a tropical rainforest stays local, so that whatever vapour is
produced, it is recycled by winds in the Hadley cell, see Section 6.2 below. Deforestation in the Amazon area
is replaced by food crops, and evapotranspiration from those is similar to that from the natural vegetation.
Figure 14. Quote: “Global freshwater use — that is, withdrawals for agriculture, industry and municipal uses
— has increased nearly six-fold since 1900. This is shown in the chart. Globally we use approximately 70
percent of freshwater withdrawals for agriculture.” (OurWorldinData, 2014).
The graph in Figure 14 shows 4,000 billion m3
(or tonnes) in 2014, and therefore estimates 2,800 billion
tonnes used for agriculture.
The withdrawal of large quantities of fresh water from underground aquifers, and from one country’s river
before it flows into a downstream country, is causing a Water Crisis. This problem has been the subject of
films such as:
2016 – ‘Pumped Dry: The Global Crisis of Vanishing Groundwater’, 63 minutes on YouTube.
2018 – ‘World’s Water Crisis Explained’, 18 minutes on YouTube. This film contains a graph by the United
Nations Food and Agriculture Organisation showing fresh water withdrawals increasing from 1,000 billion
tonnes in 1940, to 4,250 billion tonnes in 2010. The film advises that around 70% of it is used for agriculture.
2019 – ‘Brave Blue World’ – 50 minutes on Netflix.

14. 6. The Water Cycle
“The water cycle refers to the continuous movement of water on, above, and below the surface of the Earth.
Water can change phase among liquid, gas (water vapor), and solid (ice) at various places in the cycle. The
importance of the water cycle for life on land cannot be overstated ... without the water cycle, most of the
terrestrial life on Earth could not exist. When water vapor condenses in the formation of clouds, large
amounts of heat - called latent heat - are released into the atmosphere. Latent heat is an important source
of energy in the development of thunderstorms and hurricanes.” (University of Arizona, 2021).
“The phase changes of water combined with its unique heat-related properties are intimately involved in all
aspects of climate and weather. Water transfers and stores heat on an immense scale, and thereby evens
out the temperature differences between day and night, summer and winter, tropics and polar areas.”
(University of California, San Diego, 2021).
Figure 15. Since 1950, the increase of evapotranspiration from crop irrigation in the Northern Hemisphere
has been significantly increasing atmospheric water vapour during the late Spring and Summer months. Since
year 2000, condensation has released at least an extra 2,300 billion tonnes of latent heat energy, plus
precipitation, to the environment every year.
6.1 Latent Heat Transfer
The evaporation of water to the vapour phase needs input of heat without raising the temperature of the
water. At the boiling point of 100o
C, it takes 2,260 KJ/Kg to convert the water phase to the gas phase.

15. Evaporation can occur without reaching the boiling point – puddles after rain soon evaporate when dry
conditions return – and at 30o
C, water needs close to 2,400 KJ/Kg to change phase (Engineering Toolbox.
2021).
Latent heat transfer is defined as ‘the flux of heat from the Earth's surface to the atmosphere that is
associated with evaporation of water at the surface and subsequent condensation of water vapor in the
troposphere.’ (memrise.com, 2021).
Using the quantity of water vapour flux due to Northern Hemisphere crop irrigation of 2,300 billion
tonnes/year and the latent heat per kilogram of 2,400 KJ/Kg, the heat energy stored in the invisible vapour
over the crop fields is:
2,300 x 1012
Kg x 2.4 x 106
J/Kg = 5,520 x 1018
joules/year, or 5,520 exajoules/Summer.
This quantity is almost 10 times the total energy consumed for all human activities of 583.9 exajoules in 2019,
as described in Section 1 above.
6.2 Atmospheric Circulation
Over the major parts of the Earth's surface there are large-scale wind circulations present. The global
circulation can be described as the world-wide system of winds by which the necessary transport of heat
from tropical to polar latitudes is accomplished (UK Met Office 2). Atmospheric circulation is defined as ‘the
large-scale movement of air, and the means by which thermal energy is distributed on the surface of the
Earth’ (memrise.com, 2021).
Figure 16. (internetgeography.net, 2021).
The air in the atmosphere moves in response to differences in temperature at the equator (warm) and the
poles (cold). This movement of air is called global atmospheric circulation. (internetgeography.net, 2021).
Water vapour released by transpiring plants in northern mid-latitudes is carried towards the Arctic by winds
acting in the Ferrel cell. On reaching cooler latitudes, the vapour condenses to form clouds, accompanied by
the release of the latent heat energy acquired during evaporation. When cloud droplets grow large enough,

16. they fall to the surface as precipitation, causing at least 2,300 billion tonnes of extra rain/year in the Northern
Hemisphere. Due largely to Earth’s rotation, swirling atmospheric wind patterns can generate heat waves,
storms, tornadoes, and hurricanes. In addition to storms, extra heat energy and rainfall in northern areas has
caused melting of glaciers, permafrost and Arctic ice.
6.3 Brown Ocean Effect
Quote: “When a tropical storm or cyclone makes landfall is usually begins to lose its energy, but sometimes
conditions on the land can resemble the moist environment of the ocean maintaining and even increasing
the power of the storm. The ground must be very wet or saturated and so this land 'mimics' the sea - and
hence the name 'brown ocean effect'. The high amount of moisture in the soil (and crops), then allows a high
rate of evaporation, which then acts as a source of heat energy for the storm or cyclone, technically known
as latent heat - similar to the process over the sea.” (UK Met Office 3).
The 'brown ocean effect' was first investigated following the 2007 US Tropical Storm 'Erin' when it made
landfall across the Texan coast and then intensified as it moved inland over Texas and Oklahoma bringing
huge amounts of rainfall. The conditions were repeated with Tropical Storm 'Bill' which developed on 16
June 2015. These states have installed major irrigation systems over the Ogallala aquifer for late Spring and
Summer crop growth on naturally arid land.
The ‘brown ocean effect’ is an observed weather phenomenon involving some tropical
cyclones after landfall. Normally, hurricanes and tropical storms lose strength when they make landfall, but
when the brown ocean effect is in play, tropical cyclones maintain strength or even intensify over land
surfaces. While these systems are highly common in the United States and China, Australia is the most
conducive environment, where such storm systems are called agukabams. One source of the brown ocean
effect has been identified as the large amount of latent heat that can be released from extremely wet soils
(Wikipedia 2021).
7. Conclusions
1. Satellite observations of Arctic sea ice extent, and observations of Northern Hemisphere temperatures and
glaciers provide evidence of a marked warming over the last 50 years.
2. The atmospheric concentration of carbon dioxide has increased – worldwide - from 3.15 parts in 10,000 in
1960 to the present 4.12 parts in 10,000 by volume.
3. Over the last 41 years, there has been no significant change to temperatures and glaciers in latitudes below
45 degrees South, and no significant change to the extent of Antarctic sea ice. These observations cast doubt
on the hypothesis that increasing concentration of atmospheric carbon dioxide is an important contributor

17. to climate change. Further doubt was cast in 2009, when two German expert Mathematical Physicists (Gerlich
and Tscheuschner, 2009) advised that “there are no common physical laws between the warming
phenomenon in glass houses and the fictitious atmospheric ‘greenhouse effect’.”
4. Consumption of energy from human activities is not significant relative to the energy arriving from the Sun
of approximately 3,500,000 exajoules/year. Around 90% of human-activity-energy is consumed in the
Northern Hemisphere, with the greater portion being used in cold Winter conditions, giving rise to Urban
Heat Islands around towns and cities.
5. The additional, that is above-natural, water vapour flux created by evapotranspiration from Northern
Hemisphere crop irrigation amounts to at least 2,300 billion tonnes per year. Most of this extra vapour is
added to the atmosphere during late Spring and Summer months over naturally-arid, mid-continent land.
6. Evapotranspiration of 2,300 billion tonnes of water vapour from crop irrigation absorbs 5,520 exajoules of
the Sun’s energy as latent heat. This quantity is approximately 10 times the amount of non-renewable energy
consumed for all other human activities. Latent heat energy is released to the environment when the vapour
condenses, adding to extreme weather conditions, such as heat waves, storms, tornadoes, and hurricanes.
7. Following condensation, as the clouds move to cooler conditions, the cloud droplets grow larger and fall
as at least 2,300 billion tonnes of extra rain. The release of extra energy and rain in northern areas during
Summer months has resulted in increased flooding, and significant melting of Himalayan and Greenland
glaciers, permafrost and Arctic ice. Artificial rain, created by evaporation of the water pumped from
underground aquifers to irrigate crops, adds to rising sea level.
8. The Arctic area has suffered reduced albedo due to less reflective ice and snow, leading to the marked
reduction of Summer ice after 1995. Increased absorption of the Sun's rays on ground clear of ice and snow
adds to the warming effect.
9. Latent heat transfer combined with additional rainfall resulting from crop irrigation explains the observed
changes to Northern Hemisphere temperatures and sea ice extent, while having little or no effect in latitudes
greater that 45 degrees South.
10. In many areas, crop irrigation to feed the ever-increasing population has depended on reserves of
freshwater in underground aquifers. These reserves are running low. The impending water crisis is a major
problem facing humanity.

18. References
bp Company: Statistical Review of World Energy, 69th
Edition, published June 2020.
Breeze, P., Power Generation Technologies (Third Edition), Elsevier, ISBN: 97800810263112019, February
2019.
Chaisson, E. J.: http://www.csun.edu/~dtf46560/630/Misc/CHAISSON-GlobalHeatingFromEnergy-2008.pdf ,
last access: 05 April 2021.
climate4you.com:
https://climate4you.com/SeaIce.htm#Sea%20ice%20extension%20in%20a%20longer%20time%20perspecti
ve, last access: 08 April 2021.
climatechangepost.com: https://www.climatechangepost.com/russia/agriculture-and-horticulture/, last
access: 10 April 2021.
Ekholm, N.: "On The Variations Of The Climate Of The Geological And Historical Past And Their
Causes". Quarterly Journal of the Royal Meteorological Society. 27 (117): 1–
62. Bibcode:1901QJRMS..27....1E. doi:10.1002/qj.49702711702, 1901.
Engineering Toolbox: https://www.engineeringtoolbox.com/water-properties-d_1573.html, last access:
2021.
ESA: https://earth.esa.int/web/guest/featured-image/-/article/pio-xi-glacier-chile, last access: 03 April 2021,
2016.
Geocraft: https://www.geocraft.com/WVFossils/Carboniferous_climate.html , last access: 08 April 2021.
Gerlich, G. and Tscheuschner, R.D.: Falsification of The Atmospheric CO2 Greenhouse Effects Within the
Frame of Physics, International Journal of Modern Physics B, Vol. 23, No. 3 (30 January 2009), 275-364 (World
Scientific Publishing Co.), 2009.
Gimeno, L., Vázquez, M., Nieto, R., and Trigo, R. M.: Atmospheric moisture transport: the bridge between
ocean evaporation and Arctic ice melting, Earth System Dynamics, 6, 583–589, 2015.
Gordon, L. J., Steffen, W., Jonsson, B. F., Folke, C., Falkenmark, M., Johannnesen, A.: Human modification of
global water vapor flows from the land surface. www.pnas.org/cgi/doi/10.1073/pnas.0500208102, 2005.
Hinkel, K. M., and Nelson, F. E.: Anthropogenic heat island at Barrow, Alaska, during winter: 2001–2005, J.
Geophys. Res., 112, D06118, doi:10.1029/2006JD007837, 2007.

19. Houghton, Sir J.: Global Warming, The Complete Briefing, Third Edition 2004, Chapter 3, Cambridge University
Press.
hse.gov.uk: https://www.hse.gov.uk/carboncapture/carbondioxide.htm, last access: 10 April 2021.
internetgeography.com: https://www.internetgeography.net/topics/what-is-global-atmospheric-
circulation/, last access: 08 April 2021.
Leuagro: http://leuagro.com/?page_id=1949, last access 10 April 2021.
Le Treut, H., Somerville, R.: IPCC Report AR4, Chapter 1, Historical Overview of Climate Change Science, 2007.
MacCracken, M.C., and Luther, F.M.: Detecting the Climatic Effects of Increasing Carbon Dioxide", United
States Department of Energy, DOE/ER 0237, Dec. 1985.
memrise.com: https://app.memrise.com/course/420479/a-level-geography-key-definitions/2/
Myhre, G., Shindell, D.: IPCC Report AR5, Chapter 8, Anthropogenic and Natural Radiative Forcing, 2013.
NASA: https://www.nasa.gov/press-release/long-term-warming-trend-continued-in-2017-nasa-noaa, last
access: 03 April 2021.
New York Times: https://www.nytimes.com/1988/06/24/us/global-warming-has-begun-expert-tells-
senate.html, 1988.
New York Times: https://green.blogs.nytimes.com/2010/09/09/the-irrigation-juggernaut/, 2010.
NIWA: https://niwa.co.nz/atmosphere/our-data/trace-gas-plots/carbon-dioxide , last access: 04 April 2021.
NOAA: https://oceanservice.noaa.gov/facts/sea-ice-climate.html , last access: 02 April 2021.
NSIDC1: https://nsidc.org/cryosphere/seaice/index.html , last access: 02 April 2021.
NSIDC2: http://nsidc.org/arcticseaicenews/2014/10/2014-melt-season-in-review/, last access 02 April 2021.
NSIDC3: http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ , last access: 08 April 2021.
NSIDC4: http://nsidc.org/soac, last access: 06 April 2021.
Sciencing: https://sciencing.com/percentage-water-vapor-atmosphere-19385.html , last access: 08 April
2021.
Scott, M. and Hansen, K.: https://earthobservatory.nasa.gov/features/SeaIce, last access: 02 April 2021,
2016.

20. Scripps Institution of Oceanography.:
https://scrippsco2.ucsd.edu/graphics_gallery/mauna_loa_and_south_pole/mauna_loa_and_south_pole.ht
ml , last access 03 April 2021.
Serreze, M. C., Barrett, A. P., and Stroeve, J.: Recent changes in tropospheric water vapor over the Arctic as
assessed from radiosondes and atmospheric reanalyses, J. Geophys. Res., 117, D10104,
doi:10.1029/2011JD017421. (2012).
theconversation.com: https://theconversation.com/farmers-are-drawing-groundwater-from-the-giant-
ogallala-aquifer-faster-than-nature-replaces-it-100735, 2018.
theguardian.com 2012: https://www.theguardian.com/environment/2012/may/20/world-aquifers-rising-
sea-levels. Last access: 10 April 2021.
theguardian.com 2021: https://www.theguardian.com/environment/2021/feb/18/great-barrier-reef-
found-to-be-in-failing-health-amid-calls-for-urgent-action, last access: 10 April 2021.
UK Met Office 1: https://www.metoffice.gov.uk/hadobs/hadcet/data/download.html , updated.
UK Met Office 2: https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/global-
circulation-patterns, last access: 08 April 2021.
UK Met Office 3: https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-
weather/hurricanes/brown-ocean-effect, last access 08 April 2021.
University of Arizona:
http://www.atmo.arizona.edu/students/courselinks/fall14/atmo336/lectures/sec1/water.html
University of Oxford: https://www.geog.ox.ac.uk/research/climate/rms/series.html
University of San Diego: http://earthguide.ucsd.edu/virtualmuseum/climatechange1/09_1.shtml, last
access: 07 April 2021)
University of Weliington, NZ: https://www.wgtn.ac.nz/news/2017/02/explaining-new-zealands-unusual-
growing-glaciers, last access: 03 April 2021, 2017.
Wikipedia: https://en.wikipedia.org/wiki/Brown_ocean_effect, last access: 11th
April 2021.
Ye, H., Fetzer, E, J., Wong, S., Behrangi, A., Yang, D., and Lambrigtson, B. H.: Increasing atmospheric water
vapor and higher daily precipitation intensity over Northern Eurasia. Geophysical Research Letters, 42 (21),
9404-9410. DOI:10.1002/2015GL066104, 2015.