5. Quantification of the action of water as refrigerant
According to physics and thermodynamics, the thermal fate of heated ices
described schematically in Figure 3 can be estimated quantitatively in
terms of conductive heat exchanges using the specific heat of ice
melting (333.55 KJ/Kg), and the specific heat capacities of solid ice
(2.110 KJ/Kg/°C) and of water (4.184 KJ/Kg/°C), the presence of salts in
sea water being neglected (Engineering Tool Box, 2003).
Let us take year 2018 as example, 17.2°C being the generally accepted
global average temperature common to low atmosphere and ocean surface
water. The 2018 global ice imbalance was 1.5 trillion tonnes assumed
similar to the estimate of 2017 deduced from Figure 4 in (Slater, 2021).
Let us take -20°C as average temperature of global ices according to the
value retained to evaluate ice imbalance (Slater, 2021). According to
the specific heat capacity of ice, 1.5 trillion tonnes of ice at -20°C
required about 0,063 ZJ to reach 0°C, the melting temperature of ice.
The temperature of ice and that of the formed liquid water remained
constant at 0°C during the melting of the whole mass of ices that
required c.a. 0.50 ZJ of thermal energy according to ice latent specific
heat of fusion. The melting of 1.5 trillion tonnes of ice yielded 1.5
1015 Kg of liquid water at 0°C that required c.a.
0.108 ZJ to reach 17.2°C according to the specific water heat capacity.
The heat energy necessary to turn the disappeared ices at -20°C to water
at 17.2°C was thus c.a. 0.67 ZJ. Therefore, 0.346 ZJ eAHR (60% of the
0.576 ZJ heat energy consumed in 2018) was enough to cause 52 % of the
2018 imbalanced ice. This estimation does not take into account the
injection of Joules in the atmosphere by mammalians (humans, cattle and
animals with hot blood, hydrogen-using rockets, and criminal wildfires.
Based on lung volume and on breathing frequency, the contribution of 7.5
billion humans and 1 billion cattle heads to eAHR was less than 0.02 ZJ
and thus rather negligible. In addition to eAHR, volcanoes contribute to
heat Earth from inside. In 2018, 80 volcanoes were active, the Hawaii
eruption being the largest with c.a. 0.76 109 cubic
meters of flowing lava. Assuming density, specific heat capacity and
difference of temperature of lava being 2.6, 840 J/Kg/°C and 1000°C,
respectively, the heat released after cooling was c.a. 0.002 ZJ.
Assuming an average of 0.001 ZJ/volcano, heat released by volcanoes was
c.a. 0.040 ZJ raising non-radiative heat energy introduced in the
atmosphere to c.a. 0.4 ZJ, an amount about 4% smaller than the c.a. 9
ZJ rAHR corresponding to 0.8 W/m2 taken as minimal
estimate of the annual mean radiative forcing in the 2000’s applied to
the whole surface of the planet. This large difference of magnitude has
already been pointed out in the literature (Chaisson, 2008; Zhang &
Caldeira, 2015) but for different systems and under different
conditions. Anyhow, based on physics and thermodynamics, the dominant 9
ZJ rAHR [(27 ZJ if radiative forcing was 2.3W/m2(IPCC, 2014)] should have caused much greater ice loss than the 1.5
trillion of tonnes estimated for 2018 that required only 0.67 ZJ of heat
energy to turn lost ice at -20°C to water at 17.2°C.
Since in 2018, temperature and oceans rises were reported 0.79 °C and
3.7 mm respectively, and according to the 4.184 KJ/Kg/°C water heat
capacity, oceans stored about 4.4 ZJ leaving 4.6 ZJ unabsorbed (c.a.
22.6 ZJ in case of 2.3 W/m2 forcing) and thus
available to heat the rest of the planet and double the global
temperature, something against observations and logic.
Amounts of heat exchanges that involved water and water interphase
equilibria were obtained using thermodynamics and physics and can hardly
be challenged. In contrast, the radiative forcing may be questioned in
terms of overestimation or even inconsistency as pointed out by some
scientists (Scirocco, 2018). As an alternative, the refrigerator model
suggests evaporation as heat absorber, in addition to ice melting.
Evaporation may well explain the absorption of 4.6 ZJ by evaporation.
Indeed, the capacity of ocean to absorb heat by a thin layer of
evaporated water is approximately 81.2 ZJ/dm/°C using 2.25 KJ/Kg/°C as
specific heat of evaporation of water. Therefore, 5 mm of evaporated
ocean water are basically able to absorb and compensate the warming
effect due to a 4.6 ZJ radiative forcing but this goes against global
warming since glace melting and evaporation are physical phenomena that
normally should compensate warming globally with locally temperature ups
and down and enhanced climatic events in strength and frequency as
discussed in the previous sections. In other words, global warming in
distant future should be less important than presently predicted.
Evaporation is not the only factor that may affect climate-related
predictions in distant future.