**3. The science of climate change**

The tendency of CO2 and other gases to trap heat is often summarized as the "greenhouse effect" in which solar radiation penetrates the earth's atmosphere but only 30 percent is reflected into space [15]. This acts as a warming blanket such that the earth's average temperature supports terrestrial life. Without naturally occurring GG, Earth's average temperature would be near 0 °F (or − 18 °C) instead of the much warmer 59 °F (15 °C) that currently exists [16]. The five main gases that have significant global warming potential [GWP] are CO2, methane (CH4), nitrous oxide (NO2), fluorinated gases and water vapor [17]. These are potent trappers of infrared wavelength energy as the covalent chemical bonds between them are relatively weak such that the molecule remains intact despite adding energy. Nonetheless, these gases are not equivalent in their GWP as this is dependent on their concentration, their ability to trap infrared wavelengths, (i.e. heat), and their atmospheric functional lifespan. GWP uses CO2 as a benchmark when calculating 100-year relative effects. For example, methane is 84-fold more effective in

trapping heat but it persists in the atmosphere for only slightly more than a decade reducing its 100 year impact to 28 times that of CO2 [18]. Notably, CO2 released today will persist in the atmosphere for 300–1000 years such that it will have a much greater overall temporal impact. In comparison, nitrous oxide persists in the atmosphere for more than a century such that its short term and long-term effects are identical at 28 fold the impact of CO2 [19]. Fluorinated gases are even more potent as R-22, the most common refrigerant currently in use, has a 100-year GWP of 1,810, which is almost 2,000 times the potency of CO2, such that one pound of R-22 is nearly as potent as a ton of CO2 [20]. This same reference stated that releasing one 30-lb tank of R-22 into the atmosphere is nearly equivalent to the CO2 emitted by driving 7 additional cars each year, (source data available at CARB's Cool California Calculator). Notwithstanding these effects, water vapor currently exerts the greatest greenhouse effect at this time given its higher concentration in the atmosphere. While the effects of water vapor are relatively short-lived, the amount of water vapor in the atmosphere will increase as warmer atmospheres correlate with greater degrees of humidity [21]. The positive feedback generated by adding additional water vapor into the atmosphere is such that a 1 °C temperature increase from excess CO2 production has a net effect of increasing atmospheric warming by 2 °C [22]. Ice (solid water) also has an impact on climate change as snow and ice reflect a greater degree of incoming sunlight than does water known as the "albedo effect" [23]. Polar ice cap shrinkage leads to reduced reflectivity or reduced albedo. Conversion of polar ice in the Northern Hemisphere to liquid water leads to a relatively darker ocean surface, which facilitates the absorption of additional heat from the sun, thus melting large masses of ice in the ocean [24]. Melting ice will lead to a rise in sea levels coupled with more frequent storm surges leading to more frequent and intense flooding [25]. Sea level rise will result in less habitable land for terrestrial based life forms as was noted during the past interglacial period when the earth's average temperature was 1 to 2 °C warmer and sea levels were 4 to 6 meters or circa 13–20 feet higher [26]. Even with limiting global warming to 1–2 °C, many of our coastal cities will be submerged.

The most recent extreme period of relative warming in Earth's history was that of the Paleocene-Eocene Thermal Maximum (PETM) about 55–56 million years ago when the earth's mean temperature rose by 5–8 °C (9–14 °F) to an average temperature of 22.8 °C or 73 °F [27]. These authors further stated that concurrent paleoclimate data from fossilized phytoplankton and ocean sediments recorded a massive release of CO2 into the atmosphere, at least doubling or possibly even quadrupling the background CO2 concentrations. The net result was that crocodilians and palm trees thrived at the polar regions. Thus, the geological record is clear that failure to address climate change and permitting average temperatures to rise will lead to lands unsuitable for large scale agriculture and a drastic reduction in the biodiversity of the planet. Therefore, the moral imperative is to mitigate the probability of this result. The United Nations' International Panel on Climate Change (IPCC) reported that global temperatures will likely rise to 1.5 degrees Celsius above preindustrial levels in the time interval of 2030 and 2052 if GG induced warming continues at the current rate [28]. The Paris Agreement, in which all countries agreed to cooperate in order to limit average global temperature increases to between 1.5 and 2 degrees Celsius above pre-industrial levels [29]. Even if this goal is reached, climate change will have a significant impact on global ecology. Restated, it is not debatable if climate change will occur but rather that of the rapidity and the severity of the ongoing climate change.

Climate change is already having impacts. A review article stated that there is a 97% consensus within published climate research that is robust and consistent with other surveys of climate scientists and peer-reviewed studies [30]. Global weather

**207**

*Climate Change: A Forced Choice Ethical Paradigm DOI: http://dx.doi.org/10.5772/intechopen.95486*

**4. Medical model of disease**

patterns are changing such that there is less precipitation in the Western United States and greater precipitation in the Midwest [31]. Other climate change effects may be summarized as melting polar ice caps and glaciers leading to coastal flooding, loss of biodiversity, and a redistribution of species such that some are becoming extinct while others, (e.g. invasive pests and disease carrying vectors), are expanding their range [32]. All these data indicate that the earth is unwell and is suffering from the disease of global warming that has already induced permanent changes to

One approach to understanding climate change is that of the medical model of disease. This model assesses how several risk factors and causative triggers interact to produce a "disease" characterized by specific pathology that presents with a combination of symptoms and signs that help establish a diagnosis and suggest potential treatments [33]. This has been greatly enhanced using technology such as laboratory testing, imaging studies and genetic analyses. Agusti opines that this approach is more applicable to acute disease rather than chronic disease as chronic diseases tend to induce secondary effects and produce additional comorbidities leading to ever increasing adverse impacts on the afflicted organism. The chronic disease model integrates more risk factors and triggers that interact, (*e.g.* aging and smoking), which induce damage to several organ systems concurrently, (*e.g. c*ardiovascular and respiratory) [34]. Type two diabetes mellitus, a disease that results in elevated blood sugar, provides an example. This disease occurs from inadequate insulin production and/or insulin resistance that often leads to multiorgan dysfunction. These comorbidities include large vessel complications such as stroke and cardiovascular disease as well as microvascular complications such as nephropathy, retinopathy, and polyneuropathy. The net result is a significantly reduced quality of life, wherein the person survives but in a compromised state. To avoid these complications, the disease process must be identified, confirmed as a diagnosis, and treated as soon as practical. In the early stages of type two diabetes, the body can tolerate some excess glucose, but there is a threshold beyond which compensatory mechanisms fail and hyperglycemia begins to exert its deleterious effects. In this analogy, global temperature rise is equivalent to increasing blood sugar levels that must be identified and reduced before long-term complications arise. Restated, it is better to recognize and treat an asymptomatic person with an elevated blood sugar with oral medications than to begin aggressive high dose insulin when that person is admitted to an intensive care unit with a hyperglycemic coma. While an asymptomatic person may deny their disease's existence despite laboratory testing, it is only a matter of time before the consequences are self-evident such that denial is no longer possible. However, a person's willingness to accept a medical diagnosis, seek treatment and adhere to that treatment is highly variable between individuals and reflect

the global environment and portends greater degrees of climate change.

cultural background, education, and acceptance of scientific principles.

George Engel MD described the biopsychosocial model of disease in which social and psychological factors have a significant impact on disease development and management [35]. For example, the Pima people in the Sonoran Desert region have one of the highest rates of diabetes on the planet [36]. Their ancestors had to adapt to an environment where nutrients were scare such that evolution favored the survival of those individuals who could extract the most calories from limited food sources. Human evolutionary biology has prioritized calorie dense foods as their consumption favored survival and subsequent reproduction such that humans will consume these foods preferentially [37]. The Pima people, who did not live in an

*Climate Change: A Forced Choice Ethical Paradigm DOI: http://dx.doi.org/10.5772/intechopen.95486*

*Bioethics in Medicine and Society*

of our coastal cities will be submerged.

trapping heat but it persists in the atmosphere for only slightly more than a decade reducing its 100 year impact to 28 times that of CO2 [18]. Notably, CO2 released today will persist in the atmosphere for 300–1000 years such that it will have a much greater overall temporal impact. In comparison, nitrous oxide persists in the atmosphere for more than a century such that its short term and long-term effects are identical at 28 fold the impact of CO2 [19]. Fluorinated gases are even more potent as R-22, the most common refrigerant currently in use, has a 100-year GWP of 1,810, which is almost 2,000 times the potency of CO2, such that one pound of R-22 is nearly as potent as a ton of CO2 [20]. This same reference stated that releasing one 30-lb tank of R-22 into the atmosphere is nearly equivalent to the CO2 emitted by driving 7 additional cars each year, (source data available at CARB's Cool California Calculator). Notwithstanding these effects, water vapor currently exerts the greatest greenhouse effect at this time given its higher concentration in the atmosphere. While the effects of water vapor are relatively short-lived, the amount of water vapor in the atmosphere will increase as warmer atmospheres correlate with greater degrees of humidity [21]. The positive feedback generated by adding additional water vapor into the atmosphere is such that a 1 °C temperature increase from excess CO2 production has a net effect of increasing atmospheric warming by 2 °C [22]. Ice (solid water) also has an impact on climate change as snow and ice reflect a greater degree of incoming sunlight than does water known as the "albedo effect" [23]. Polar ice cap shrinkage leads to reduced reflectivity or reduced albedo. Conversion of polar ice in the Northern Hemisphere to liquid water leads to a relatively darker ocean surface, which facilitates the absorption of additional heat from the sun, thus melting large masses of ice in the ocean [24]. Melting ice will lead to a rise in sea levels coupled with more frequent storm surges leading to more frequent and intense flooding [25]. Sea level rise will result in less habitable land for terrestrial based life forms as was noted during the past interglacial period when the earth's average temperature was 1 to 2 °C warmer and sea levels were 4 to 6 meters or circa 13–20 feet higher [26]. Even with limiting global warming to 1–2 °C, many

The most recent extreme period of relative warming in Earth's history was that of the Paleocene-Eocene Thermal Maximum (PETM) about 55–56 million years ago when the earth's mean temperature rose by 5–8 °C (9–14 °F) to an average temperature of 22.8 °C or 73 °F [27]. These authors further stated that concurrent paleoclimate data from fossilized phytoplankton and ocean sediments recorded a massive release of CO2 into the atmosphere, at least doubling or possibly even quadrupling the background CO2 concentrations. The net result was that crocodilians and palm trees thrived at the polar regions. Thus, the geological record is clear that failure to address climate change and permitting average temperatures to rise will lead to lands unsuitable for large scale agriculture and a drastic reduction in the biodiversity of the planet. Therefore, the moral imperative is to mitigate the probability of this result. The United Nations' International Panel on Climate Change (IPCC) reported that global temperatures will likely rise to 1.5 degrees Celsius above pre-

industrial levels in the time interval of 2030 and 2052 if GG induced

ity and the severity of the ongoing climate change.

warming continues at the current rate [28]. The Paris Agreement, in which all countries agreed to cooperate in order to limit average global temperature increases to between 1.5 and 2 degrees Celsius above pre-industrial levels [29]. Even if this goal is reached, climate change will have a significant impact on global ecology. Restated, it is not debatable if climate change will occur but rather that of the rapid-

Climate change is already having impacts. A review article stated that there is a 97% consensus within published climate research that is robust and consistent with other surveys of climate scientists and peer-reviewed studies [30]. Global weather

**206**

patterns are changing such that there is less precipitation in the Western United States and greater precipitation in the Midwest [31]. Other climate change effects may be summarized as melting polar ice caps and glaciers leading to coastal flooding, loss of biodiversity, and a redistribution of species such that some are becoming extinct while others, (e.g. invasive pests and disease carrying vectors), are expanding their range [32]. All these data indicate that the earth is unwell and is suffering from the disease of global warming that has already induced permanent changes to the global environment and portends greater degrees of climate change.
