Energy conservation in the Earth's crust and climate change

Abstract

Among various matters which make up the earth's crust, the thermal conductivity of coal, oil, and oil-gas, which are formed over a long period of geological time, is extremely low. This is significant to prevent transferring the internal heat of the earth to the thermal insulation of the surface, cooling the surface of the earth, stimulating biological evolution, and maintaining natural ecological balance as well. Fossil energy is thermal insulating layer in the earth's crust. Just like the function of the thermal isolation of subcutaneous fatty tissue under the dermis of human skin, it keeps the internal heat within the organism so it won't be transferred to the skin's surface and be lost maintaining body temperature at low temperatures. Coal, oil, oil-gas, and fat belong to the same hydrocarbons, and the functions of their thermal insulation are exactly the same. That is to say, coal, oil, and oil-gas are just like the earth's “subcutaneous fatty tissue” and objectively formed the insulation protection on earth's surface. This paper argues that the human large-scale extraction of fossil energy leads to damage of the earth's crust heat-resistant sealing, increasing terrestrial heat flow, or the heat flow as it is called, transferring the internal heat of the earth to Earth's surface excessively, and causing geotemperature and sea temperature to rise, thus giving rise to global warming. The reason for climate warming is not due to the expansion of greenhouse gases but to the wide exploitation of fossil energy, which destroyed the heat insulation of the earth's crust, making more heat from the interior of the earth be released to the atmosphere. Based on the energy conservation principle, the measurement of the increase of the average global temperature that was caused by the increase of terrestrial heat flow since the Industrial Revolution is consistent with practical data.

Implications:

This paper illustrates “pathogenesis” of climate change using medical knowledge. The mathematical verification is based on the principle of energy conservation. The central idea or clou in this paper is that fossil energy is a thermal insulating layer in the earth's crust, the thermal insulating layer was destroyed after human large-scale mining of fossil energy, and the internal heat of the earth was excessively released to the surface so as to cause climate change.

Introduction

Climate change has become a scientific problem of world interest. There is a growing appreciation of the need for change (Wouter et al., 2009). The Intergovernmental Panel on Climate Change (IPCC) in 2007 reported a global average temperature rise 0.74°C in the updated 100 years (1906 to 2005). The linear warming trend over the last 50 years is nearly twice that for the last 100 years. Eleven of the last 12 years (1995–2006) rank among the 12 warmest years in the instrumental record of global surface temperature (since 1850). Global average sea level rose 0.17 (0.12 to 0.22) m in the total 20th century. About twice as much warming (0.2°C per decade) would be expected. Even if all greenhouse gases and aerosols were held constant at year 2000 levels, a further warming trend would occur in the next two decades at a rate of about 0.1°C per decade (IPCC, 2007).

Two driving forces chiefly have affected the evolution of climate for eons of time: One is extraterrestrial celestial body and cosmic environment change, especially with solar activities, and the other is activities in various spheres and layers in the earth system interior, such as the crust change, ocean kinematics, volcanic eruption, and so on.

Many studies and observed data proved that the climate change was mainly influenced by nature before the industrial revolution, so it is characterized by natural variables. But in modern times, human activities' role in climatic change is becoming more and more important, which becomes a main factor accounting for climate change.

The heat that is first delivered by thermal conduction of the internal heat of the earth to the surface and that then will transfer from the surface to the air is called terrestrial heat flow. Heat flow equals the product of strata thermal conductivity and vertical geothermal gradient numerically. The global average heat flow value is only 50 mW/m², but the space–time distribution is inhomogeneous and its variation scope is much larger than that of the average value. Enough evidence shows that shallow heat flow is a mirror of deep heat flow (Maocang and Xiaoqing, 1995).

It is an accepted opinion within the meteorological circle that climate changes for more than 3 mo are caused by the outer parts of the earth's atmosphere, rather than the intra-atmosphere. This means that climate change after 3 mo should have factors outside the aerosphere to partake of.

Studies by Maocang et al. (Maocang, 1992; Maocang and Xiaoqing, 1995) show that “the basic cause of climate change is in the sold Earth,” but the atmosphere is given a response (also called adjustable adaptation) position basically, clearly putting forward a “geocentric theory of climate change.” Ground temperature is a physical quantity of the measurement of underground thermal energy. And compared with changes of temperature, the changes of deep soil temperature are more conservative and hysteretic. As one part of the underlying surface, the change of it may cause the change of many physical quantities of atmospheric circulation and ocean, which means various thermodynamic processes in the solid Earth circulation are bound to be involved in the changes of climate (Maocang and Jian, 1994). Geotemperature and sea temperature directly show the thermal content of the earth's surface, which basically come from solar radiation and thermal radiation from the crustal interior. Affected by heat sources, the crustal surface fall into a changeable temperature zone, homoeothermic zone, and increasing temperature zone. The changeable temperature zone is the quite thin zone of the earth's surface affected by solar radiation, temperature periodic variation of day and night, and a year, even a century, can be observed in the zone because of periodic variation of solar radiation energy, and the annual temperature that varies according to certain rules and gradually falls off with depth. The changeable temperature zones, in most plains the hill regions, are 15–20 m thick (Jun et al., 1990). Atmospheric temperature only affects the temperature of land surface, and the deep geotemperature and sea temperature mainly reflect the thermal radiation from the crustal interior. Many years of results of satellite observation indicated that the variation scope of solar constant is only approximately 1‰, not enough to cause global climate change. What is the increasing extent of temperature that is caused by the doubling of greenhouse gases (CO₂, CH₄, etc.)? Maocang et al. (2004) once calculated with the ancient historical data and made a conclusion that the increasing extent of temperature that is caused by the doubling of greenhouse gases less than or equal to 1°C. This demonstrates that there are no supported ancient historical materials for the result of simulation, 1.5–4.5°C/(2 × CO₂), which results from various numerical models at home and abroad. A high-temperature stream coming from the mantle is an important condition for organic matter evolution, as well as for the main factors of climate change (Dou et al., 2003). There is heat diffusing continuously from the inside to the surface of the earth. Sometimes (e.g., after an earthquake) it may reach a maximum in some areas (such as at a crater or some places near a volcanic rift zone), and is called as “jump of the ground temperature” or “geothermal anomaly” (Maocang and Jian, 1990). According to monthly geothermal anomaly data collected by observation stations in China from 1954 to 1985, among a total of 70 times of observations, the results of 53 times of “underground suddenly warming” are caused by geothermal abnormalism.

It has been proven that forcing change of the underlying surface is one of the most important causes of climatic anomaly (Shukla, 1984). It is well known that tropical sea temperature anomalies, taking El Niño as an example, can lead to climate response in global scale. The essence of climate change lies in its being nonadiabatic (Ronghui, 1991), so the heat anomaly of underlying surface is mainly responsible for climate change. There are similarities between temperature change and geotemperature. Besides, its centers of warm and cold change are corresponding to each other and the geothermal change and temperature are synchronous. The difference is that the change of temperature, compared with geotemperature, is more obvious and frequent in an hour, whereas the change of geotemperature is more obvious over a long period of time.

Matter and energy are transferred from the earth's interior to the atmosphere ceaselessly, which affects atmospheric processes and eventually results in climate change (Xiaoqing et al., 2004).

First of all, it is necessary to carry on the research on “pathogenesis” of climate change to deal with climate change. A correct understanding of “pathogenesis” of climate change is highly important for us to realize current and future climate change. On the mechanism study of change of climate, it is humans' endless exploit of fossil energy that caused the destruction of thermal insulation and sealing of Earth's crust, and it is the increase of terrestrial heat flow that caused rises of geotemperature and sea surface temperature that finally caused the change of climate, which is often ignored by humans.

Life processes of the human body and all living creatures need the proper temperature. Subcutaneous fatty tissue under the epidermis has a stronger thermal isolation function than skin, the thermal conductivity of which is only one-fourth that of other tissue, making the internal heat within the organism not easy to transfer to skin surface to lose; it is important to keep the body warm in a low-temperature environment. Coal, oil, oil-gas, and fat belong to the class of hydrocarbons and their thermal insulation functions are exactly same. Coal, oil, and oil-gas are just the earth's “subcutaneous fatty tissue,” and guarantee not much emission of the earth's internal heat to the surface, making the biosphere always have a proper temperature condition. There is considerable evidence and many historical records to prove that human's extraction of fossil damaged the crustal heat-resistant sealing, causing the increase of terrestrial heat flow and the rise of geotemperature and sea temperature, which is exactly the “pathogenesis” of climate and environment change over the past hundred years. That is, humans' large-scale extraction of fossil energy leads to the damage of the crustal heat-resistant sealing, bringing about the increase of heat flow, thus transmitting excessive heat to the earth's surface, which results in the rise of geotemperature and sea temperature, making global warming. This paper calculates that the increase of heat flow has made the global average temperatures rise by 0.84°C from the industrial revolution to 2010 based on the principle of energy conservation, which is consistent with the actual measurement record.

Data and Methods

Energy conservation in the earth's crust and the heat flow change

The law of conservation of energy says that different forms of energy are capable of transforming from one form into another, from one system into another, and total energy is conservative during its transformation and transmission. Energy can neither be created nor be destroyed; it can only transform from one state to another. Thus, initial energy equals final energy (E_i = E_f). We can know from the law that the decrease of some form of energy must increase other form of energy; if the energy of one object decreases, the energy of other object must increase. As for hydroelectric station generating electricity, a high dam is built to let the water possess potential energy (Ew), striking the turbine to turn to convert potential energy to mechanical energy (Em), and a generator is driven by the rotating turbine and at last mechanical energy turns into electrical energy (Ee). Here, the joules of water's potential energy equal the joules of mechanical energy, which also equal the joules of electrical energy. Energies are totally equal in these three forms, or energy is not conservative (Figure 1).

Figure 1. Patterning of energy conservation: (a) water energy–mechanical energy–electrical energy, and (b) geothermal energy–chemical energy–fossil energy.

Based on mathematical law, when A = B, and B = C, then A = C. So Ee and Ew are equal exactly, and vice versa, and we can know Ew or Em from a given Ee without any observation and experiment. Similarly, fossil energy is produced by a series of complex chemical reactions under geothermal high pressure and high temperature. Fossil energy also obeys the law of energy conservation because it is the transformation of energy, that is, geothermal energy is converted to chemical energy, then chemical energy is converted to fossil energy, on the scale of “the window for generating coal, oil, and oil-gas.” Its thermal-resistant effect strengthens continuously with fossil energy produced constantly. It leaves “the window for generating” when temperature or pressure does not reach the threshold producing fossil energy, which also means no fossil energy is produced any longer and a normal heat flow appears. Coal, oil, and oil-gas exist in the regions where there are hot spots that reach the temperature and pressure for “the window for generating coal, oil, and oil-gas,” and these regions need heat insulation and sealing; instead, this is not occur. So the gross heat value of all fossil energy sources mined by the human is calculated equal to the increased part of the heat flow. There is no need to observe human mining.

Suppose the value of terrestrial heat flow is 100 units before fossil energy is produced, of which 80 units is within “the window for generating fossil energy,” so 80 units of fossil energy is produced after a long period of geologic time formation, and thus the heat flow value becomes (100 – 80) unit; this is normal heat flow. The heat flow value turns into (100 – 79), that is, (100 – 80) + 1 units, when humans mine 1 unit of fossil energy sources; when 2 units of fossil energy source are mined, the heat flow value becomes (100 – 78), that is, (100 – 80) + 2 units, and so on; the +1, +2, and so on represent the increased part of the heat flow. Suppose again that humans mined 6 units of fossil energy since the industrial revolution.

Heat flow (heat flow, Qhf), total heat flow (total heat flow, Qthf), fossil energy (fossil energy, Qfe), total fossil energy sources mined by the human (N), then are shown in Figure 2.

Figure 2. Heat flow in the different periods on Earth: (a) heat flow on Earth before fossil energy to be produced is 100(Qhf) = Qthf; (b) heat flow on Earth after fossil energy to be produced is (100 – 80)Qhf = Qthf – Qfe; (c) now heat flow on Earth is [(100 – 74) or (100 – 80) + 6]Qhf = (Qthf – Qfe)+ N.

Evidence for the heat flow change before and after fossil energy extraction

Fossil energy sources such as coal, oil, and oil-gas are highly sensitive to geological environment factors like temperature, pressure, and so on; tectonic events during the geologic evolutionary process inevitably lead to a series of physical, chemical, structural, and constructional changes of coal, oil, and oil-gas. Thus, the phenomenon is visible that the large scale of mining fossil fuel damages crustal heat-resistant sealing and makes the heat flow increase.

Geotemperature tends to increase with the depth of strata and appears the law of linear change. Strata where geotemperature stays constant all year round are the homoeothermic zone. The variable-temperatures zone (or solar warming layer) is affected above by solar radiation heat to show periodic change. The increasing temperature zone (or warming zone) is below the homoeothermic zone, and is principally subject to the internal heat of the earth and gets warmer with increasing depth. Geotemperature increase with 100 m increase of depth is called the geothermal gradient. Geothermal gradient is from 1.6 to 3.0°C/km in normal areas. If the geothermal gradient is >3.0°C/km, it is regarded as positive anomalies, and if the geothermal gradient is <1.6°C/km, it is regarded as negative anomalies. The geothermal gradient is obviously affected by stratum structure and properties of thermal physics, and not only reflects well the variances in temperature along strata section but also has regional characteristics. For example, the geothermal gradient can be up to 10–100°C/km or even higher in crustal motion regions. In tectonically stable regions, it is 1.6–3.0°C/km, usually near to the normal. Therefore, geothermal gradient, like heat flow density, is an important parameter to represent the geothermal state of a region, and as a scale to judge whether geotemperature is normal or abnormal.

Hongyang et al. (2007) observed the geotemperature change in the Huainan mining area, Anhui province, China. They found that the geothermal gradient in Panji area (2.80–3.80°C/km) is significantly higher than in the old area (1.10–1.82°C/km), and the average geothermal gradient in the west wing of Panji No. 3 mining area (3.42°C/km) is higher than in the east wing (3.14°C/km); both are positive anomalies. In the old area, a long period of mining activities generated many cracks in the rock strata, making the upper water of low temperature filter down, cooling the rock strata, coupled with coal forming the drainage of the mining area, then forming the circulatory system of cool water and improving the cooling effect of rock strata. After the analysis of some abnormal factors, Hongyang argues that the heat source that causes geothermal anomaly in Huainan Diggings comes from the interior of the earth and points out that compared with other sedimentary rock, the thermal coefficient of coal is extremely low, so a coal seam, especially a thick one, has a higher geothermal gradient; comparing coal measure strata that contain less amounts of coal seams, the one that contains a large amount of coal seams has a better effect of insulation of subterranean heat. Through analyzing data from the test of geotemperature of 30 drilled holes of deep exploration and the mine in the Panzhihua coal mine, Sichuan Province, China, Guangming et al. (2009) argue that high temperature zone is increased with the increase of the depth, and its heat source comes from magma. The deepest coal mine in Britain is in Lancashire, about 1,300 m. The deepest wellbore is in a coal mine in Wales. Yugal K. Verma has measured 26 original geotemperature values in five coal mines in the south of coal mine at Wales and found out that geothermal gradient is 26.2 m/°C at 1220 m depth and the average original geothermal value is 45.7 °C . The other 14 data items measured in the latter half of the middle of coal series have shown that because of the great density of the coal seam and high thermoresistance, the geothermal gradient is only 18.7°C, and as a result, thermal conduction is lower (Shaolin, 1985).

The Xuechun et al. (2003) study of Dagang oilfield's paleogeotherm suggests that the paleogeotherm changed evidently in the early stage and tended toward stability in the late stage during the formation of oil-gas in Dagang as time went by. This demonstrates that paleogeotherm change is controlled by regional structure, and the peak district of the paleogeotherm is also an area of strong tectonic activity and frequent hydrothermal activity. Therefore, paleogeotherm change is closely related to and has causal relationship with regional tectonic environment and thermodynamic condition. The period of paleogeotherm change represents the time of strong crustal motion and tectogenesis, as well as the peak of oil and oil-gas accumulation. The statistical data of heat flow also shows that heat flow value in geologic unit decreases with age increase of the last tectonic-thermal event it undergoes (Pollack et al., 1993). The studies of Peng et al. (Peng et al., 2007; Jun et al., 1995; Shejiao et al., 2000; Hu et al., 2000) display that the monolithic geothermal gradient is between 13.0 and 39.9°C/km in Southern Huabei basins, an average of 25.3 °C/km. The heat flow value is between 30 and 89.6 mW/m², with an average of 53.7 mW/m². Compared with other geological unit in mainland China, its heat flow value is higher than low temperature “cold” basins in western China like Tarim Basin (44 mW/m²), Junggar Basin (42.3 mW/m²), and others, but lower than high-temperature “warm” basins in eastern China like Bohai Bay Basin (69 mW/m²) and Songhua River–Liaoning Basin (70 mW/m²), and others. From these data it is clearly seen that heat flow value is low in unmined oil and gas fields (Tarim and Junggar Basin), and high in those oil and gas fields of large scale and long time of extraction (Bohai Bay Basin: Dagang Oilfield; Songhua River-Liaoning Basin: Daqing Oilfield, Jilin Oilfeld, and Liaohe Oilfield), and heat flow value is intermediate between the two (southern north China Basin: southern Huabei Oilfield). Based on the work of the predecessors and thermal conductivity of rocks and heat generation rate, Nansheng (2001)calculated deep temperature according to the theory of heat conduction, analyzing the deep temperature distribution (below 4000 m), through these heat flow values. Nansheng concluded that the statistical average heat flow value in Qaidam Basin is 52.6 ± 9.6 m-W/m², but on a local wellhead, the heat flow value is more than 70 mW/m²; this is a thermal exceptional area of the basin resulting from the damage of crustal heat-resistant sealing due to excessive extraction of petroleum.

Petroliferous basins are rich in resources such as oil, oil-gas, geothermal, and so on. Huichao et al. (2008) analyzed the paleogeothermal gradient of the Cenozoic era in Jiyang depression by using authigenic illite crystallinity and chemical elements of authigenic chlorite, and the research indicates that the paleogeothermal gradient of Cenozoic era in Jiyang depression is 37.2–38.2°C/km. Yuling et al. (2003) concluded that the present geothermal gradient in Jiyang depression is 35.5°C/km through the measurement of temperatures of 703 drillings, which brings up the fact that yhr paleogeothermal gradient is larger than the present geothermal gradient. The Zhanhua east zone in Jiyang depression is located in the estuary region, Dongying city. Exploration indicates that this area is a multiple oil and gas accumulation area with resourceful oil and gas and varieties of oil reservoir. By means of the drilling thermometry and vitrinite reflectance R_O data and based on the analysis of the present geotemperature field in this zone, applying a multiphase thermal evolution model combining lithosphere and the basin scale, Benhe et al. (2001) had restored thermal history in Zhanhua east zone and drew the conclusions that (1) the present geothermal gradient is 35.8°C/km, and the geothermal gradient is high in Gudao and Kendong region, more than 37°C/km; and (2) the heat flow value in the early Paleocene was 83.6 mW/m², equivalent to the heat flow value of the modern mobile rift valley. The basin gradually tends to become cooler since the Paleocene; two recoveries occurred in the process, but the recovery range grew smaller. Today the heat flow value is 63 mW/m², close to the global average heat flow value. Also, (3) the main source in this region, hydrocarbon source rock, came through a continuous heating process, and nowadays still in its “generative window”; there is a large space of petroleum occurrence in depth. Thermal evolution is to the advantage of the hydrocarbon generation. It is thus clear that heat flow is prevented effectively after oil and gas generation.

Evidence for rise of geotemperature and sea temperature due to heat flow increase

The Jun et al. (2008) analysis of the variation trend of soil temperature at deep layer in Lhasa shows that the average annual geotemperature has a very significant warming trend in Lhasa during the last 45 years, with a tendency rate of 0.58–0.69°C/10 yr; compared with the increase range of average temperature in a corresponding period, the geotemperature growth is more. At the same time the geothermal observation by meteorological stations widely distributed in seasonal frozen regions and permafrost regions in the former Soviet Union indicated that annual average geotemperatures in most meteorological stations present a rising trend in a century (Gilichinsky et al., 1998). The permafrost layer temperature beneath the surface of the Swiss Alps has been ascending at the rate of 0.5–1.0°C/10 yr since the 1980s (Haeberli et al., 1993). The measuring temperature of the frozen earth across Alaska from north to south shows that from 1980 to 1996, the temperature in this region has risen from 0.5°C to 1.5°C (Osterkamp and Romanovsky, 1999). The permafrost layer temperature along the Qinghai-Tibet Plateau Fenghuo Mountain has risen 0.2–0.3°C from the 1960s to the 1990s (Shaoling, 1993). Linear rising temperature rate of the surface is larger along the south and north of the Qinghai-Tibet railway; especially the south averages 0.56°C/10 yr (Dongliang et al., 2005). The geotemperature of permafrost frozen soil rose by 0.8°C in Amue area of Daxinganling during the 1970s–1990s (Zhongwei et al., 1993). Geotemperature had gone up 0.3–0.6°C since 1958 to 1990 in the upper Heilongjiang River valley (Shengqing and Zhanchen, 1993). The Huijun et al. (Huijun et al., 2006; Dongliang et al., 2005), observations on geotemperature characteristics and deterioration ways along the Qinghai-Tibet highway and railway indicate that the frozen soil has extensively deteriorated, geotemperature has risen, maximal thaw depth has deepened in summer, frost depth has decreased in winter, and thickness of frozen soil layer has got thin, or has disappeared completely, in some areas in the global warming during the past decades. At present, frozen soil downward deterioration rate is about 6–25 cm yr⁻¹ in the Qinghai-Tibet line, but upward has reached 12–30 cm yr⁻¹ and the annual average temperature and geothermal increase rate are respectively 0.33°C/10 yr and 0.37°C/10 yr. On the whole, gthe eothermal increase rate is higher than that of the air temperature. Geothermal increment is noticeably faster than air temperature during the relatively warm period.

According to a report of the British weekly New Scientist on December 12, 1994, global warming is not consistent with the climate change predicted on the basis of the concentration of greenhouse gas in the earth's atmosphere. Researchers believe that the southwest Pacific Ocean is a valuable criterion for monitoring the degree of climate change because of fewer cities and less atmospheric pollution in this area. The New Zealand National Institute of Water and Atmosphere Research offers firsthand information for the gradual warming of the Indian Ocean depths. Nathan Bindoff, Antarctica and Southern Ocean Environmental Cooperation Center, Hobart, Tasmania, Australia, calculated that the temperature of ocean 250 to 1500 m deep has gone up about 0.5°C at 32˚ south latitude after comparing recording temperature data from vessels sailing the Indian Ocean in the early and the middle 1960s with recording data from the Darwin Research Ship in 1987. Bindoff thinks that this temperature change in the depth of the sea is an important mark for overall global climate change. He pointed out that there is very little seasonal fluctuation when measuring the temperature in the depths of the oceans. This means that less observation can obtain a relatively accurate result in comparison with measuring at sea level. The Indian Ocean has proved to be the third ocean with deep-water warming. Similar facts published by Bindoff in 1992 have proved that temperature of the southwest Pacific Ocean rises almost at the same speed. The team led by Gregorlo Parrilla, Institute of Oceanography, Spain, discovered that the North Atlantic is also warming (Qingshan, 1995).

After the study of 60 places' geotemperature data in South Africa, Pollack (1991) found that temperature has risen by 0.3–0.8°C in the area during the past 100 years, an an average of 0.55°C, in line with the research results on global change. Through the analysis of a large number of borehole temperature measurements in extreme northern Alaska (in the Arctic Circle),. Lachenbruch, a well-known geothermist and academician of the U.S. National Academy of Sciences (Lachenbruch et al., 1991), made a conclusion that the temperature of this district has risen 2–4°C from the last decades to the last 100 years. Cermak, the vice-chairman the of International Heat Flow Commission and director of the Physical Institute, Academy of Sciences of Former Czechoslovakia (Cermak and Bodri, 1991), studied more than 30 places' borehole measuring temperature data in Cuba, pointing out that temperature has risen by 2–3°C in Cuba during the past 200–300 years. Mareschal at the University of Quebec and Jessop at the Geological Survey of Canada. (Hugo and Mareschal, 1991), reported that the temperature has risen by 1–2°C in the area during the past 100–200 years on the basis of the study on the mass of measuring temperature data in eastern and central Canada, and most temperature changes deduced from geotemperature data coincide with the observation results of weather stations.

Heat flow increase caused by fossil energy mined on a large scale has the same heat as the fossil energy total quantity mined by human regurgitation to the earth's surface all the time. The heat makes a climatic system response.

Results

Large-scale fossil energy mining leads to heat flow increase; heat flow equal to the total quantity of fossil energy mined by humans regurgitates to the earth's surface all the time, which makes a climatic system response. Calorific value is an important index for derived calorie from fossil energy in energy chemistry. It is the energy contained in a unit mass (or volume) of fossil energy source. There are higher calorific values and lower calorific values. The former is the amount of total energy the fossil energy contains; the latter is only practically available energy. There is a 5% difference between higher calorific value and lower in coal and oil, and 10% in oil-gas.

The lower calorific value of raw coal is 20,908 KJ/kg, the lower calorific value of crude oil is 41,816 KJ/kg, and the lower calorific value of oil-gas is 38,931 KJ/m³.

The specific heat of air is about 1.0 × 10³ J/kg-°C. This indicates that 1 kg air absorbs (or releases) 1.0 × 10³ J calories when temperature rises (or reduces) 1°C; the total quality of the earth's atmosphere is 5000 trillion tons.

On a globe scale, 295.9 billion tons of raw coal, 115.4 billion tons of crude oil, and 71 trillion m³ of oil-gas were exploited, from the industrial revolution in England to 2010 (http://www.in-en.com/; http://www.in-en.com/coal/resource/intl/2011/04/INEN_8465 5.htm). Making use of these numerical values, we can calculate the degree of global warming caused by the damage of crustal heat-resistant sealing and heat flow increase over the past hundred years. For convenient calculation and accurate data, we convert 100 million tons, trillion cubic meters, into kilograms, cubic meters; convert kilojoules into joules; and convert lower calorific value into higher calorific value, that is, lower calorific value plus lower calorific value multiplied by 5% (coal, crude oil) or 10% (oil-gas). The structure of stratum is very complicated, because there is no vertical heat flow back-streaming after the destruction of the crust's heat-resistant sealing, and heat flow has spread through different kinds of structures, such as stratum, fissure, and karst cave, but all are in the same direction, generally to the earth's surface, which is difficult to observe or repeat in experiment. Oceans cover almost 71% of the earth. Because huge seawater mass and the heat capacity of water are huge, a slight elevated temperature of ocean has little or no effect on climate. And land, which covers almost 29% of the earth's surface, continuously “heats” the atmosphere like a thick “radiator,” so the calculation of total heat of the increased part of heat flow should multiply by 29%, the result of which is the true reflection of the index of the increase of global temperature.

Nowadays the contribution of heat flow increase to climate change

Raw coal: higher calorific value

(1)

Heat flow produced by 295.9 bn tons of raw coal

(2)

Crude oil: higher calorific value

(3)

Heat flow produced by 115.4 billion tons of crude oil

(4)

Oil-gas: higher calorific value

(5)

Heat flow produced by 71 trillion m³ of oil-gas

(6)

Heat flow produced by total fossil energy (restricted in coal, oil, and oil-gas)

(7)

The heat released into the atmosphere by land absorbed

(8)

These heat values shall also be made an elevated average global temperature:

Given a 1 × 10³ J heat providing a temperature rise of 1°C in 1 kg atmosphere, how hot will 4.2349763952 × 10²¹ J heat make 5 × 10¹⁸ kg air be?

If the temperature will rise X°C, it follows that:

(9)

When 5000 calories provided per unit time is enough to maintain the temperature of 20°C in a room, a constant 5000 calories input must be maintained. If greater than 5000 calories, room temperature will rise above 20°C, and for less than 5000 calories, room temperature will fall below 20°C. It is the same with the earth; the exploitation of fossil energy sources and the damage of crustal heat-resistant sealing are just like opening a heat-insulating “window”; 4.2349763952 × 10²¹ J calories of the Earth's interior flow into the Earth's surface to maintain the globe warming up 0.84°C, and with constantly mining fossil energy sources year after year, the global temperature goes up year by year (Figure 3).

Figure 3. Mechanism map of heat flow increase: (a) sketch map of heat flow increase; (b) description of heat flow increase.

Rate of global warming in the next every decade

In 2010, over the world, the output of raw coal is 7.273 billion tons, crude oil 4.054 billion tons, oil-gas 3.1933 trillion m³. Suppose the world output of raw coal, crude oil, and oil-gas remain at the 2010 level rather than cutbacks; then we come to a conclusion that the average global temperature will rise by 0.27°C in the next 10 years.

Reviewing the fourth report of the Intergovernmental Panel on Climate Change in 2007, we have a clearer idea about the causes of climate change formation in the recent 100 yr. The report points out that global average temperature rise is 0.74°C (0.56–0.92°C) over the 20th century (1906 to 2005). It is expected the temperature will rise by 0.2°C per decade in the next two decades. Even if all greenhouse gas and aerosols keep stable at the level of 2000, a further warming will occur in the next two decades rising by 0.1°C per decade. It is calculated in this paper that the global rise in temperature range is 0.84°C in 2010 and the average global temperature rise is 0.27°C after 10 yr, totally consistent with the numerical prediction of IPCC (a temperature rise by 0.2°C per decade in next two decades, 0.1°C every 5 yr).

Climate change reflects the change of the whole Earth system in the atmosphere, anything but a solitary activity inside the atmosphere (Jorgen et al., 2008). The increase of heat flow makes geotemperature and sea temperature rise, leading to climate change, various environmental changes, and geological disasters (Koji, 2011; Remy et al., 2008; Marcel, 2010; Hans et al., 2008; Andrei, 2010).

Energy distribution changes under the conditions that crustal heat-resistance sealing is damaged and heat flow continually increases. Oceanic and atmospheric circulation and temperature field distribution in the atmosphere are irregular, disturbing weather and climate change rules, and extreme weather events emerge more and more frequently. In addition to temperature, precipitation, drought, hailstorm, lightning, and sandstorms going to extremes, becoming unpredictable, such natural disasters as hurricanes, earthquake, and so on continuously refresh the record of strong violence and destructive force. The destruction of crustal heat-resistance sealing and excessive heat flow from the earth's interior to the surface also makes core circulation, mantle convection, and earth-atmosphere circulation change, and there will be more uncertain factors on Earth in the future.

Conclusion

The sun's illumination and normal heat flow are main factors to keep the normal temperature of the earth's surface. As a result of the destruction of heat insulation seals of the earth's crust are caused by humans' mining of fossil energy, the increased part of the terrestrial heat flow is the main heat source of climate change in the last hundred years.

Heat flows from the warmer to the cooler body and the cooler body absorbs heat from the warmer, in accordance with the thermophysical properties. Hence, heat from the earth's interior spreads to the earth's surface through thick rock strata once the thermal insulation layer is destroyed, but various rock strata are not thermal insulators; the combustible substances of coal, hydrocarbons, and so on are the finest natural thermal insulating materials.

Is there a huge fireball of high temperature and high pressure in the earth's interior? Do coal, oil, and oil-gas in the crust have high efficiency and persistent thermal insulation function? Do hard crustal rock layers have a thermal barrier effect? Chinese archaeologists excavated Mawangdui No. 1 West Han dynasty tomb at Changsha in 1972 and Ming dynasty Ding mausoleum at Beijing in 1956. Both are accidentally made objective and prolonged “scientific experiments” on thermal insulation of coal, oil and rock, thus presenting a striking contrast. Masonry was not used in Mawangdui No. 1 Han dynasty tomb but white plaster mud containing grease was applied to seal the tomb; all the objects in the tomb appeared well preserved, including the coffin, the body, silk, and grain after being buried for more than 2100 years (Chuanxin, 2005; Chuanxin, 2005) . In contrast, up to six layers of white marble of the hardest fabric were used to build from the cemetery to outer coffin in the Ming dynasty Ding mausoleum, still unable to retain the host of the tomb; emperor Wanly's corpse had corrupted to the nail in less than 400 years, and only a withered skeleton was left behind (Fangliu, 2008; Qian, 2003). No matter how thick the mausoleum and no matter how hard the rock, they can't avail against even normal heat flow, let alone ever-increasing heat flow. This fully indicates that coal and hydrocarbons have efficient, sustained thermal insulation. Coal, oil, and oil-gas are the earth's “subcutaneous fatty tissue,” and thermal insulation layer of heat-resistant sealing in the crust; if a combination of white plaster mud and charcoal perfectly seals up Mawangdui No.1 Han dynasty tomb, then a combination of coal, oil, and oil-gas perfectly seals up the crust. The crustal thermal insulating layer has great significances in insulating the heat of the earth's interior from the surface, keeping the ecological balance of nature and organism evolution.

Data analysis shows that the global temperature fell down after 1940, exactly in the time of rapid increase of CO₂ density.

It can be seen from Figure 4 and Figure 5 that CO₂ concentration in atmospheric decreased when the global climate got warmer suddenly in 1925. From the 1940s to the 1970s was the time when CO₂ grew quickly but the global temperature declined sharply. Macroscopically, the rise of temperature exactly elevated atmospheric CO₂ concentration. The relationship between atmospheric CO₂ concentration and climate is being challenged because recently the rise in temperature range is far lower than the temperature predicted by scientists based on the rise of CO₂ concentration. A lot of abnormal phenomena from climate and nature make climate change caused by a greenhouse effect questioned (Michel, 2008; Rainer, 2009). In fact, a large portion of the CO₂ going into the air is absorbed by the sea to change gradually into carbonate and deposit onto the seafloor, forming rock, or transferring to the land though sea shells, skeletons of aquatic organisms, and dust fall. Carbonate absorbs CO₂ from air to become bicarbonate, dissolving in water and then returning to the ocean (Ulf, 2008). Observations and simulation research show that more than half of the CO₂ released by fossil energy is assimilated by vegetation and oceans in the last 10–20 yr, while only about a half left in the atmosphere. It is obvious that a leading contributor to global warming is not a greenhouse effect or greenhouse effect aggravation.

Figure 4. Change trends of the mean annual air temperature in the last century in the earth (IPCC, 2001).

Figure 5. Annual increment of atmospheric CO₂ concentration in the last century in the earth (Boden et al., 1990; Boden et al., 1992).

The study of Amanda Scott of the National Oceanic and Atmospheric Administration (NOAA) in the United States indicates that global warming is irreversible and tend to accelerate, and climate warming will continue for 1,000 yr even if the human race stops greenhouse gas emissions. This is just strong evidence that extraction of fossil energy damages crustal heat-resistant sealing to increase heat flow, thus causing global warming. Today, there are many phenomena that scientists cannot justify. For example, the upward melting rate of frozen Earth is faster than the downward rate in the Qinghai-Tibet plateau at present. According to existing popular view, the permafrost melting caused by temperature rise due to the greenhouse effect should be downward instead of upward. As human beings sustainably mine fossil energy and fiercely damage the crustal heat-resistant sealing, heat flow increases, and thus geotemperature and sea temperature rise progressively; carbon dioxide melting in the crust and sea will release into the atmosphere, and atmospheric CO₂ concentration is still higher than that before the industrial revolution even if human beings stop CO₂ emissions.

We can calculate average raising temperature range in each time or in the future around the globe in this way as long as we know the total volume of mined fossil energy, identical with the measured value (Table 1).

Table 1. Output/total of globe fossil energy with heat flow increase and global average temperature rise (units: 100 million tons, trillion m³)

Time	Coal	Oil	Gas	Land heat flow increase J	Average warmed °C
1880–1980	1500/1500	517/517	30/30	1.9858314224 × 10^21	0.39 (1980)
1981–2005	1125/2625	440/957	20/50	3.5106974454 × 10^21	0.70 (2005)
2006–2010	334/2959	197/1154	21/71	4.2349763952 × 10^21	0.84 (2010)

This fully justifies that the “pathogenesis” of the climate and the environment change just result from the destruction of crustal heat insulation seals and the increase of terrestrial heat flow. The present damage is not continuous extraction of fossil energy, but the human race has not recognized this, and neither do most experts and scientists, which is extremely dangerous.

Through nearly a hundred years of the human's large-scale extraction of fossil energy, the crustal heat-resistant sealing has been artificially destroyed, and there are more and more cracks caused by mining, and bigger; so does the heat flow increase year by year. Nowadays, in accordance with law of energy conservation, the value of heat flow increase is exactly equivalent to the sum of the heat value of total fossil energy mined by the human from the industrial revolution. The human was beginning to dig coal before industrial revolution, but productivity was extremely low at that time and it could not affect the crustal heat-resistant sealing.

In conclusion, the following evidence shows that the destruction of heat insulation of the earth's crust from exploiting the fossil energy and the expansion of the earth's heat are the main reasons for climatic change:

1.	The high-temperature stream coming from the mantle is not only an important condition for organic matter evolution, but also the key factors of climate change have been proved by scientists through a great quantity of research (Dou et al., 2003).
2.	The matter and energy transferred from the earth's interior to atmosphere ceaselessly, which affects atmospheric processes and eventually results in climate change (Xiaoqing et al., 2004).
3.	The hydrocarbon prevents heat flow effectively after fossil energy generation (Huichao et al., 2008; Yuling et al., 2003; Benhe et al., 2001).
4.	Based on scientific observations, heat flow could reach a very high value and have “underground suddenly warming” phenomena occur after fossil energy is mined (Nansheng, 2001).
5.	Global observations vindicate that deep geotemperatures and sea temperature have sensible rise (Hongyang et al., 2007; Guangming and Kemin, 2009; Shaolin, 1985; Xuechun et al., 2003; Pollack et al., 1993; Peng et al., 2007; Jun et al., 1995; Shejiao et al., 2000; Hu et al., 2000; Nansheng, 2001; Huichao et al., 2008; Yuling et al., 2003; Benhe et al., 2001; Jun et al., 2008; Gilichinsky et al., 1998; Haeberli et al., 1993; Osterkamp and Romanovsky, 1999; Shaoling, 1993; Dongliang et al., 2005; Zhongwei et al., 1993; Shengqing and Zhanchen, 1993; Huijun et al., 2006; Dongliang et al., 2005; Pollack, 1991; Cermak and Bodri, 1991; Hugo and Mareschal, 1991) .
6.	Mawangdui No. 1 west Han dynasty tomb when excavated showed that white plaster mud containing grease and charcoal could effectively block heat flow for more than 2100 years (Chuanxin, 2005; Chuanxin, 2005).
7.	Built in six layers of very hard stone, the Ming dynasty Ding mausoleum does not have thermal insulation action (Fangliu, 2008; Qian, 2003).
8.	Thermal conductivity of fossil energy in the earth's crust is lowest (Jiyang and Zhanxue, 2001).
9.	The results of mathematical verification that heat flow increase resulted in climate change are entirely consistent with measured values.

We focus on how many holes, how big the crack is, and how much the amount of heat flow increases as a result of human extraction of fossil energy above the sealing layer, instead of on how large the crustal heat-resistant sealing layer is. It will take a million years, ten million years, even a hundred million years of geological age to repair these holes and cracks by nature. Climate change is taken seriously in the globe, and international society has taken many measures to fight it; however, all attempts are not to the point that current human endeavors work to no avail.