Values in Climate Policy

David Morrow

• Publisher: Rowman & Littlefield International
• Year: 2019
• ISBN:
  9781786609496
• Edition: 1
• Topic: Philosophie
• Subtopic: Ethik & Moralphilosophie

Children born today in the Maldives may someday have to abandon their homeland. Rising seas, caused by climate change, could swallow most of their tiny island nation within their lifetime. Their fate symbolizes the double inequity at the heart of climate change: those who have contributed the least to climate change will suffer the most from it. All is not lost, however. The scale and impact of climate change depends on the policies that people choose. How quickly will we eliminate our greenhouse gas emissions? How will we do it? Who will pay for it? What will we protect through adaptation? How will we weigh the fortunes of future generations and the natural world against our own? Answers to questions like these reflect a constellation of value judgments that deserve close scrutiny. In addition to providing essential background on the science, economics, and politics of climate change, this book explores the values at stake in climate policy with the aim of shrinking the gap between climate ethics and climate policy.

Chapter 1

The Physical Science of Climate Change

Making sound judgments and decisions about climate policy requires a solid understanding of the causes and possible impacts of climate change. This includes knowing how we know what we know about climate change—and what we know we don’t know about it. This chapter introduces the fundamentals of climate science by surveying the history of the field, from its origins in the early nineteenth century to the present. It concludes by summarizing the current state of our knowledge about key topics, focusing on the impacts of climate change.

A BRIEF HISTORY OF CLIMATE SCIENCE

The story of climate science begins much earlier than most people realize. It predates the environmental movement of the 1960s by more than a century. It is always hard to say exactly when and where a story begins, but for our purposes, we can start with a scientific paper written in 1824.

Fourier: The Atmosphere Absorbs Heat

Like many other scientific discoveries, the discovery of climate change emerges as a byproduct of other scientific work. In 1824, the French mathematician and physicist Jean-Baptiste Joseph Fourier sets out to determine what regulates the Earth’s temperature. He does this with the help of some mathematical formulas he had published two years earlier in a book called The Analytic Theory of Heat. These formulas describe how heat flows through and between objects.

In his paper on the Earth’s temperature, Fourier emphasizes the difference between what he calls “luminous heat” and “dark radiant heat.” Luminous heat is heat transmitted by visible light, such as sunlight, which both heats and illuminates the globe. “Dark radiant heat” is energy radiating in a form that the human eye cannot see, such as the heat emanating from a radiator or from a cast-iron skillet on a hot stove. We can feel this kind of heat if we put our hands near its source, but we cannot see it without special equipment.

It is worth putting Fourier’s ideas into modern scientific terminology. What he calls “luminous heat,” we call “visible light.” What he calls “dark radiant heat,” we call “infrared radiation.” Like visible light, infrared radiation is a form of electromagnetic radiation.¹ Every object emits infrared radiation, with warmer objects emitting more of it than cooler objects. For instance, warm-blooded animals in a cool environment emit more infrared radiation than the inanimate objects around them.

As Fourier points out, when sunlight hits the Earth’s surface, the surface heats up as it absorbs some of the energy from that light. Because the surface warms, it emits more infrared radiation. Some of that infrared radiation gets absorbed by the atmosphere. And in the same way that the surface warms when it absorbs visible light, so the gases in the atmosphere warm when they absorb infrared radiation. Fourier hints at the possibility that by absorbing infrared radiation, the atmosphere plays an important role in regulating the temperature of the Earth, but he does not provide a detailed account of the process.² Later scientists, however, find his work suggestive enough to credit Fourier with the idea that the atmosphere traps the Sun’s energy because it can somehow capture that energy as it radiates back toward space in the form of “dark radiant heat.”³

Pouillet: The Atmosphere Warms the Earth

Another French physicist, Claude Pouillet, follows up on Fourier’s ideas about a decade later. In 1838, Pouillet publishes an ambitious paper analyzing the Sun’s effects on Earth’s temperature. In his paper, he goes beyond Fourier’s work to provide a detailed explanation of what later scientists call the “greenhouse effect”—that is, the atmosphere’s effect of warming the globe by trapping heat that the surface absorbs from the Sun.

Imagine, Pouillet writes, that you have a hot surface suspended above a colder surface. The hot surface radiates energy toward the colder one; the colder one absorbs this energy, warms up, and radiates energy back toward the hotter one. Assuming this process continues uninterrupted for some time, the two will eventually settle into an equilibrium where the colder surface has warmed enough to radiate energy away as quickly as it absorbs it. To make this more concrete, think about a skillet on a hot stove. As the skillet absorbs energy from the stove, it heats up. What keeps the skillet from heating up so much that it melts? The answer lies in the fact that as it warms, the skillet emits more infrared radiation. Eventually, it radiates away as much energy every second as it absorbs from the stove. The burner and the skillet have reached equilibrium.

We can understand Pouillet’s next insight by asking what happens if we put a lid on that cast-iron skillet. As the skillet radiates energy away, the lid will absorb that energy. As the lid warms, it, too, will radiate energy in all directions—including back down toward the skillet. The skillet is then absorbing energy from two directions: from the burner below and the lid above. So, the skillet will warm further until it is radiating enough energy to equal the combined inputs from the burner and the lid. Pouillet shows that because the atmosphere allows sunlight to pass directly through it but absorbs the infrared radiation rising from the Earth’s surface, it acts a bit like the lid on a skillet: it captures outgoing infrared radiation and re-emits some of it back toward the surface. The overall effect is to warm the Earth’s surface, compared to what it would be if it were warmed only by the Sun.⁴ He concludes that in virtue of this tendency, the atmosphere’s influence on Earth’s temperature “is much more considerable than has hitherto been supposed.”⁵

It is worth noting two things about Pouillet’s work. The first is that Pouillet reveals the greenhouse effect to be a natural phenomenon, without which the Earth’s surface would be dramatically colder. Modern calculations show that without the greenhouse effect, Earth’s global average temperature would be roughly 30°C (54°F) colder than it is now.⁶ That is a spectacularly large difference, given that the last ice age was only about 5°C or 6°C colder than it is now. So we need to be careful to distinguish between the atmosphere’s natural greenhouse effect, without which Earth would be inhospitably cold, and the strengthening of that greenhouse effect, which, as we will see, is the physical cause of global warming. Second, notice that although he relies on the fact, already well established by then, that the atmosphere absorbs outgoing radiation, Pouillet offers no explanation as to how it does this.

Foote and Tyndall: The Discovery of Greenhouse Gases

Although Pouillet doesn’t know exactly how the atmosphere absorbed infrared radiation, two very different scientists arrive independently at the same explanation of that fact at about the same time. The first, Eunice Foote, is an amateur scientist working in upstate New York. The second, John Tyndall, has trained in some of the finest universities in Germany and holds the prestigious position of professor of physics at the Royal Institution of Great Britain. For various reasons, Tyndall generally gets credit for the discovery, but Foote gets there first.

Foote conducts a series of simple experiments to determine how the Sun’s rays affect the temperature of different kinds of gases. Her basic setup is simple: by sealing thermometers inside glass cylinders filled with different gases, she measures how much heat the cylinders absorb when placed in the sun and how long it takes them to cool off when moved into the shade. She finds that humid air absorbs more heat than dry air does and that carbon dioxide absorbs more heat than regular air does. Furthermore, the cylinder filled with carbon dioxide takes much longer to cool off once moved to the shade. Inferring that different gases in the air affected how much the Sun’s ray warmed the atmosphere, she concludes that “an atmosphere of [carbon dioxide] would give to our earth a high temperature; and that if as some suppose, at one period of its history the air had mixed with it a larger proportion than at present, an increased temperature from its own action as well as from increased weight must have necessarily resulted.” She publishes her findings in 1856.⁷

Meanwhile, across the Atlantic, John Tyndall had been reading the works of Fourier and Pouillet. (There is some dispute as to whether he had Foote’s paper.) Intrigued by their ideas about the way heat traveled through the atmosphere, he sets out to investigate how different kinds of gases interact with “radiant heat” (that is, infrared radiation).⁸ He had been taught, he writes, that invisible gases are almost powerless to trap heat, but his painstaking experiments conclusively show otherwise.

At the risk of oversimplifying, we might describe his experiments as follows: He builds a long, airtight tube that looks something like a telescope. Near one end, he places a metal cube that he could heat to a specific temperature. Because he controls its temperature, Tyndall can calculate how much energy the cube radiates into the tube. At the other end of the tube, he places a device to measure how much energy emerges from the tube. When he uses an air pump to remove all air from the tube, 100 percent of the heat that enters the tube comes out the other side. But when he pumps various gases into the tube, less than 100 percent of the heat emerges from the tube; the rest, Tyndall shows through careful testing, is being captured by the gas in the tube.

Over months of rigorous experimentation in 1859 and 1860, Tyndall draws the following conclusions: Pure oxygen, pure hydrogen, and pure nitrogen absorb very little heat, allowing 99.67 percent of the heat emitted by the cube to pass through the tube. Water vapor, carbon dioxide, carbon monoxide, ozone, and hydrogen sulfide all capture considerably more than these “pure” gases. Tyndall estimates carbon dioxide’s absorptive power to be 100 to 150 times more than oxygen’s, depending on the circumstances. (The exact absorptive power, he finds, depends on how much of the gas is already present.) But these gases’ absorptive powers are “feeble” compared to some others’, such as ethylene, which absorbs 81 percent of the heat entering the tube.

Turning to the issues raised by Fourier and Pouillet, Tyndall conducts some experiments specifically aimed at determining how much heat normal atmospheric air captures. When he strips the carbon dioxide and water vapor from the air—which would leave almost nothing but nitrogen and oxygen—he finds that the air absorbs very little heat. The untreated air from his laboratory, however, captures fifteen times as much heat—mostly, he calculates, because of the water vapor. On the basis of these experiments, Tyndall writes, “It is exceedingly probable that the absorption of the solar rays by the atmosphere, as established by M. Pouillet, is mainly due to the watery vapour in the air.”⁹ In other words, Tyndall concludes that water vapor, carbon dioxide, and various other gases are capable of absorbing infrared heat and “it is exceedingly probable” this explains the atmosphere’s effect of warming the planet. Because we now refer to this effect as the greenhouse effect, we use the term “greenhouse gases” to refer to the heat-trapping gases that cause it, such as water vapor and carbon dioxide.

A few years later, Tyndall stresses that the greenhouse effect is essential to life as we know it. Once again, he attributes the effect primarily to water vapor. He writes,

This aqueous [water] vapour is a blanket more necessary to the vegetable life of England than clothing is to man. Remove for a single summer-night the aqueous vapour from the air which overspreads this country, and you would assuredly destroy every plant capable of being destroyed by a freezing temperature. The warmth of our fields and gardens would pour itself unrequited into space, and the sun would rise upon an island held fast in the iron grip of frost. The aqueous vapour constitutes a local dam, by which the temperature at the earth’s surface is deepened: the dam, however, finally overflows, and we give to space all that we receive from the sun.¹⁰

But Tyndall also recognizes another implication of greenhouse gases’ ability to absorb heat—the same implication that Foote had pointed out a few years earlier. If the greenhouse effect depends on the concentrations of greenhouse gases in the atmosphere, then it can become stronger or weaker over time.

De Sausurre, Fourier, M. Pouillet, and Mr. [William] Hopkins regard this interception of the terrestrial rays as exercising the most important influence on climate. Now if, as the above experiments indicate, the chief influence be exercised by [water vapor], every variation of this constituent must produce a change of climate. Similar remarks would apply to the carbonic acid [carbon dioxide] diffused through the air; while an almost inappreciable admixture of any of the hydrocarbon vapours [such as ethylene] would produce great effects on the terrestrial rays and produce corresponding changes of climate. . . . Such changes in fact may have produced all the mutations of climate which the researches of geologists reveal. However this may be, the facts above cited remain; they constitute true causes, the extent alone of the operation remaining doubtful.¹¹

To use his metaphor of greenhouse gases as a heat-trapping dam, higher greenhouse gas concentrations would be like a higher dam, which would require Earth to warm up before it could “overflow” the dam and spill the extra heat into space. The question about greenhouse gases’ influence over time is, therefore, not about whether it affects the climate, but only about “the extent . . . of the operation” of the greenhouse effect.

Arrhenius: Carbon Dioxide, Ice Ages, and Global Warming

Over the next several decades, a number of other scientists specul...

Table of contents

• Preface
• Acknowledgments
• Introduction: The Maldives and the Moral Challenge of Climate Change
• 1 The Physical Science of Climate Change
• 2 The Economics of Climate Change
• 3 Values in Climate Politics
• 4 The Moral Foundations of Climate Action
• 5 Crosscutting Issues in Climate Policy
• 6 Values in Mitigation Policy
• 7 Values in Adaptation Policy
• 8 Intergenerational Justice and Climate Policy
• 9 Nature, Values, and Climate Policy
• Bibliography