One THE FOUR CLOCKS Our present perilous situation is the product of the interaction of four different realms: reality, the scientific world, public opinion, and the world of business and finance. It's useful to imagine four clocks running at different speeds, with each clock representing one of these four realms, the latter three all lagging behind the reality of climate change, but to different degrees. In the scientific realm, there is a lag built into the very structure of scientific inquiry. Science proceeds by gathering data, analyzing it, and publishing the results; from the 1980s on, we see a built-in lag of at least two years between what has actually been happening with the climate and our scientific understanding of it. The realms of public opinion and finance have lagged even further behind reality. Let's start all the clocks in 1979, the year President Jimmy Carter's blue-ribbon panel presented him with their recommendations. Clock One follows the progress of climate change itself. Hottest years in history began accumulating in the mid-1980s, and since then each decade has set new records. For instance, the 1980s counted six of its ten years as among the top ten, with 1988 breaking the all-time record for global warmth. Since 2000, every year but one has been among the top ten globally, with the warming accelerating as we approach 2023 (each of the last seven years of the 2010-2020 decade was one of the seven hottest years on record). There have been many other signals of climate change, such as a rapid acceleration of sea level rise. This clock shows that human-caused climate change has been with us since the 1980s and has been becoming ever more intense. Clock Two marks the progress of science. Despite the warnings of the Carter blue-ribbon panel, until the mid-1990s, most scientists felt that global warming relating to greenhouse gas emissions wouldn't arrive until the next century and would make its presence felt only incrementally. In part this was because, back then, those reconstructing past climates literally could not see the rapid, violent global changes that have characterized climate change since the ice ages began some 2.7 million years ago. Early tools for reconstructing global climate in the distant past had a resolution of hundreds of years, but scientists steadily improved various proxies that permitted them to look at ancient climates so that the picture of past climates emerged with ever more precision. What they saw was truly alarming and completely different from the conventional wisdom of earlier decades. By the mid-1990s, signals of extremely rapid changes in the past had become blindingly clear, and by 2003, climate science had undergone a complete paradigm shift: where once climate change was seen as stately and incremental, the consensus now was that it could be dramatic and swift. As climate scientist Richard Alley put it, the old view was that climate change was a dial; the new view, a switch. Speaking to the recklessness of not controlling greenhouse gas emissions given this new view of climate, Wallace Broecker, the pioneer of the role oceans play in climate change, was even more colorful: "Climate is an angry beast," he said, "and we are poking it with sticks." Clock Three marks the progress of public appreciation of the threat. At times this clock has advanced rapidly, and at other times it has run backward. There were periods in the 1980s and 1990s when public concern spiked. Regardless, awareness of how climate changes and whether climate is changing lags behind, by a large margin, both reality and the progress of our scientific understanding. If the first clock reflects what is happening currently, and the second clock lags by two years, the third clock has lagged the first two by as much as decades. Right now, opinion is changing rapidly, but as recently as a year ago, significant numbers of Americans still resisted the idea that humans were changing the climate-something that became scientific consensus more than twenty-five years ago-and an even larger percentage were unaware that the scientific consensus has shifted to the understanding that climate changes can be dramatic and extremely rapid. Clock Four marks the understanding of climate change in the world of business and finance, including the economics community, the markets, and investors. With a couple of exceptions, this clock lags even the public in terms of appreciation of the threat. Right now, this is changing rapidly, but until a couple of years ago, the principal way climate change captured the attention of business, economists, and investors was not how climate change might affect the economy, but rather how attempts to limit fossil fuel emissions might lower profits. This fourth clock is perhaps the least well examined and least well understood of the causes of our present dilemma, but it is also the most important. If the markets had the incentives and penalties to price in the likely future costs of climate change, the world would have acted decades ago, and we might have forestalled the changes we are seeing today. But the market did not have those incentives, and so the markets and the business community focused on the costs of changing business as usual. To justify this posture, they had to ignore increasingly clear signals from reality, as well as a scientific consensus about the dangers. That they were able to ignore these signals as long as they did turned out to be immensely consequential. Because the markets are where the money is, politicians followed, and we are left with our present situation where the clock of climate reality ticks in real time, the scientists are mid-decade, the public is in the 1990s, and, until very recently, the financial community remained stuck in the 1980s. OK, then; we have four clocks, each one running at a different pace. Clock One represents reality. The lag in the scientific clock, number two, is built into the very structure of scientific inquiry and that's not going to change. The pace of the public clock, number three, varies according to events in the timelines of Clocks One, Two, and Four (business and finance), with the weightings of these various inputs also varying over time. In this sense the public clock is passive, dependent on outside influences. For most of the last three decades, events in the real world and scientific community have been less influential on the public than the messages coming from business and finance. Today the weightings of the influences on public awareness are shifting rapidly, as evidenced by the swiftly rising alarm in the public and a growing realization in the financial community that the reality of climate change might pose more of a risk to the economy than attempts at regulation. We will dive into the current state of play with regards to climate change in later chapters, but first we need to understand how we got here. PART ONE Setting the Stage Two THE BIGGEST PICTURE Were it not for the human hand, the climate would likely still be in the sweet spot (at least for humans) that it has been in for most of the past 11,500 years. It's not a coincidence that almost all of human civilization developed during this hiatus from the ice ages, nor is it coincidence that our numbers exploded during this period, rising from about 5 million to more than 7.8 billion as of this writing. This sweet spot is a geophysical reality. Innumerable factors create a given climate, but dominant among them is where earth is positioned in space relative to the sun and how it is tilted relative to our star. Earth's orbit around the sun changes in a 100,000-year pulse. We're presently in the rounder part of this pulse, which means that earth is now at the beginning of a 100,000-year ice age cycle (note that any return to ice age conditions could be thousands of years in the future). The home planet's spin axis is now tilted about 23.5 degrees. This should accentuate the difference of the seasons, but countering that effect is where we are in the precession of that spin axis. Precession is easiest to visualize if you imagine a rod driven through earth's poles with a pen on each end. Precession would be the circle that pen draws as the spin axis shifts back and forth on a regular basis. Right now (and for the next many thousands of years, because precession also has a 100,000-year cycle), the Northern Hemisphere is tilted away from the sun when the earth is closest to the sun, and toward the sun when it is farthest. The net effect is to reduce summer-winter differences in the Northern Hemisphere, where most of the world's food is grown. That's a good thing. Humanity has been the beneficiary of other orbital dynamics. There's the 100,000-year oscillation of earth's orbit from rounder to flatter, the 41,000-year cycle that characterizes changes in the tilt of earth's axis, and the circle described every 26,000 years by the precession of that axis. Geophysicist Richard Alley notes that we would have to go back 115,000 years to find an equally warm, human-friendly set of orbital dynamics as we have enjoyed over the past ten thousand years. There are also climate cycles related to natural events here on earth, cycles with periods ranging from millions of years to the quarterly changes of the seasons. Roughly 2.7 million years ago, for instance, the Panama land bridge rose, separating the Atlantic and Pacific oceans and diverting equatorial currents. Along with some other events, this set in motion changes in how heat was distributed around the world, and, voil^, the ice ages began. Other, shorter cycles also derived from events here on the planet. During glacial periods, so-called Heinrich events drove down temperatures every 10,000 years or so (Heinrich events involve mass discharges of icebergs into the North Atlantic, whose melting then shuts down the currents that deliver significant amounts of heat to the northern latitudes). Another regular cycle of abrupt warming and then cooling recurred every 6,100 years (also described by Heinrich, this cycle involves a lagging response of the ice sheets to changes in solar radiation). There are many other cycles related to sunspots or to the interactions between the oceans and the atmosphere, including the now familiar El Ni-o/La Ni-a cycle that has a period of just a few years. There have been blips over the past 11,500 years, and those blips give a foretaste of what happens when climate goes haywire. The most recent blip was the Little Ice Age. It began around AD 1300 and was at its most intense between 1645 and 1715. The Little Ice Age ended in the mid-nineteenth century. During the Medieval Warm Period that preceded the Little Ice Age, populations exploded, with England's population tripling in the 1200s. Life spans lengthened as well. Then around 1300, climate began to whipsaw, with deep freezes alternating with hot years, droughts with floods, and Europe was battered by epic storms. Waterlogged fields became incubators for molds, pests, and disease. One of these, St. Anthony's fire, emerged from a blight that blackened kernels of rye. As described by pioneering climate historian H. H. Lamb, whole villages would succumb to convulsions, hallucinations, and gangrene. Bad as it was, St. Anthony's fire was just a warm-up act for the Black Death, which blitzed through the compromised immune systems of people weakened by famines and prior disease. The Little Ice Age stalled population growth in Europe for four hundred years, and by its deepest part in 1715, it had shortened average life spans and even shortened the people. After that cold spell, population growth resumed its upward march. From about 1.25 billion people in 1860, population has increased more than sixfold. The spread of sanitation, the discovery of antibiotics, and huge advances in plant breeding helped foster that rise. A largely unacknowledged factor, however, was that during most of that period, at least until the 1980s, the weather offered a clement context for human advance. The lesson of history is that climate is consequential. Apart from these regular cycles, unpredictable external shocks such as asteroid strikes and volcanic eruptions have had outsized impacts on the climate in the past. In April 1815, for instance, Mount Tambora in Indonesia exploded in one of the most violent eruptions in recorded history. As its ash and gases circled the globe, it cooled the climate in what came to be regarded as the "year without a summer." No external event in the past 150 years has had any lasting impact on climate. The eruption of Mount Pinatubo in 1991 gave the United States a cool summer in 1992, but its effects faded within a year. After about 150 years of stability, nested in 11,500 years of stability, climate is now changing. Over the past three decades, the changes have been coming faster, and the amplitude of the changes is more extreme. What's changing climate today could be called an internal shock or, to be more apt, a self-inflicted wound. Until the Industrial Revolution, changes in the carbon balance of the atmosphere were reactions to changes in climate. For instance, as an ice age ended, vegetation would flourish, and decay would put more CO2 in the atmosphere, which, in turn, would further enhance the warming. With our billions of tons of emissions, humanity has turned this pattern on its head, with greenhouse gases driving climate change rather than the reverse. We began our planetary-scale science experiment with our own climate in the nineteenth century, when the coal-fired "dark satanic mills" of the Industrial Revolution began a steep ramp-up of the amount of greenhouse gases we poured into the atmosphere each year. What scientists knew about climate change and when they knew it will be discussed in a separate section. What became evident in the 1980s was that, after about a century of increasing fossil fuel use and increasing human numbers, climate began warming noticeably. Other changes began to become manifest. A "five-hundred-year" flood hit the U.S. Midwest. In 1994, northern India suffered a heat wave of the century with ninety consecutive days of temperatures above 100 degrees Fahrenheit. Subsequently, India has been hit by many worse heat waves, including one in 2019 that led to speculation that parts of the country were becoming too hot for human habitation. Then Antarctica started changing, first on its outermost fringes. The Larsen Ice Shelf, the continent's northernmost and thereby most sensitive to warming, began shedding huge portions of its ice. In 1995, the Larsen A Ice Shelf disintegrated, shrinking by 2,000 square kilometers (followed by the Larsen B in 2002 and the Wilkins in 2008). In the United States, floods of the century were becoming an annual occurrence, another trend that has accelerated in the new millennium. In April and May 2011, the Mississippi River received so much water from snowmelt and a series of four storms in the Midwest that the federal government was forced to open the Morganza Spillway for the first time in thirty-seven years, deliberately flooding parts of Louisiana in order to save Baton Rouge and New Orleans. At the same time, farther west, Texas was suffering one of the most intense droughts in its history. This led to a bizarre situation in which some landowners were suffering drought on the western part of their property and floods toward the east. Excerpted from Fire and Flood: A People's History of Climate Change, from 1979 to the Present by Eugene Linden All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.
