1. Introduction
So far, the predictions of climate changes are based on hypotheses and calculations of evolutions for the distant future as reported in successive Intergovernmental Panel on Climate Change (IPCC) reports (IPCC, 2014; IPCC, 2019). These reports result from an international consensus predicting evolutions in distant future, trends being still small but nevertheless detectable today. The consensus is adopted almost universally although controversies exist, the dispatching of which is limited to articles in open access archives and magazine outlets [Dunlap & Jacques, 2013].
Until recently, global climate changes were assigned to imbalanced inputs and outputs of electromagnetic infrared radiations and to anthropogenic greenhouse gas, especially CO2, considered as sources of radiative anthropogenic heat release (rAHR) (IPCC, 2014; NASA, 2009; Mackenzie & Lerman, 2006) without consideration to any other sources of internal heat considered as negligible, notably anthropogenic heat release (eAHR) generated by the sources of energy produced and exploited by humanity. In the past, only rAHR related to greenhouse gas was taken into account and considered as absorbed predominantly by oceans (Hansen, et all, 2011; Trenberth et al., 2014; IPCC, 2019) except by a minority of climate-skeptic people. rAHR is said resulting from electromagnetic radiative flux that amounted annually from 0.5 to 1W/m2 in the early 2000s (Trenberth et al., 2014; IPCC, 2019), i.e. between 8.5 and 17 x 1021 Joules (8.5 and 17 ZettaJoules (ZJ)), the mean value being c.a. 0.79 W/m2. Regardless of their origin, the heat energy that warms Earth has to be balanced by compensation or evacuated to space otherwise the Earth would grow warmer and warmer over the years. Water cycle has been recognized for years as an important factor in climate control through evaporation-condensation phenomena despite limitations due to uncertainties on available global data (Allan & Liepert; 2010). In general, global ice was considered negligible heat absorber relative to oceans (Hansen et al., 2011). Based on outstanding facilities including satellites, NASA is the reference body to quantify ice imbalance and its role on the polar environment (Scott & Hansen, 2016). The occurrence of dramatic global ice loss is now certain, especially over the recent years, and concerns different ices, namely ice caps, sea ice, glaciers and permafrost (Rignot et all, 2019; Slater et all, 2021). Ices melting is generally considered as a source of ocean rise (Allan & Liepert; 2010) in addition to temperature-dependent dilatation. The contribution of eAHR to global warming neglected in the past is more and more regarded as an actor. The context and the history were well introduced in a recent publication (Yang et al, 2017) in which the authors proposed an algorithm to evaluate global eAHR. This approach consisted in calculations based on heat energy estimates derived from urban zones. Although there were limitations, the algorithm provided multi-scale anthropogenic heat information said reliable and useable for further research on regional or global climate changes and on urban ecosystems despite difficulties to establish ratios for converting energy consumption to anthropogenic heat.
We recently proposed a different approach (Vert, 2021) based on ice loss, fundamentals of chemistry and physics and annual global energy consumptions derived from various sources (fossil ones, biomass, nuclear electricity, etc.) found converted in oil-equivalents (Martin-Amouroux, 2015; BP, 2019). According to (Manowska, & Nowrot (2019), eAHR corresponds to c.a. 60 % of the global energy consumption, the rest being consumed to generate work. Accordingly, it was shown that anthropogenic heat released from all the energy sources in the low atmosphere between 1994 and 2017 provided enough thermal energy (7.2 ZJ) to melt 77% of the 28 trillion tonnes of disappeared ice reported recently for the same long period (Slater et all, 2021). Therefore, eAHR estimated over 23 years was effectively negligible when compared with the 8.5 to 17 ZJ estimates of annual rAHR. As ices imbalance reflects a thermal energy supply regardless of its origin, why rAHR increases assigned to CO2 greenhouse gas do not cause much greater ices imbalance than presently observed?
In attempt to bring in an answer to this question, let us consider that solar radiations have been heating the global environment over billions of years without dramatic heat accumulation despite occurrence of short and long and more or less important local ups (high temperature) and downs (glaciation) periods. The relative stability included natural greenhouse effect assumed at the origin of a 33°C excess of average Earth temperature. Nowadays, eAHR, rAHR and any other sources of heat on Earth have to be managed similarly and simultaneously to solar heat to keep Earth’s environment and climate under relative control and compatible with Life. Indeed, the Earth can be schematically considered as a huge globe with land, solid matters, surface water and atmosphere heated internally since no matter or molecule can escape in intersidereal space. Rejection of a large part of infrared electromagnetic waves to space is the consensual mechanism largely adopted in the world (IPCC, 2014 and 2019). However, if natural greenhouse effects cause a 33 °C excess of temperature on Earth, the 2-4 °C rise expected from the sole doubling of anthropogenic CO2 concentration in part per millions of atmosphere seems logically disproportionate.
A few thousand years ago, humans began to use biomass as sources of heat and light. eAHR remained very small compared with solar inputs until about 150 years ago when humans began to exploit fossil sources and, more recently, nuclear plants and renewable resources for the production of electricity in order to satisfy work, heat and comfort needs. The side effect was the appearance of eAHR in the low atmosphere in addition to rAHR in the high troposphere (Yang et al.; 2017). Earth can be compared to a mammalian body which has its metabolism generating heat in a closed space, the body. This body which burns foods has to be cooled down to keep its temperature constant. Based on this analogy, the present article aims to compare Earth’s water with the refrigerant that controls the temperature inside a refrigerator; a simpler case where inner heat has to be eliminated. Results are discussed relative to global warming and climate changes.