Under a White Sky

Under a White Sky Plot Summary

Introduction

The title "Under a White Sky" refers to a startling possibility: in the near future, our skies might turn white, not from natural causes but from a radical human intervention aimed at cooling our overheated planet. This image captures the central paradox explored in Elizabeth Kolbert's book - as humans attempt to solve problems created by our previous attempts to control nature, we find ourselves entangled in increasingly complex technical solutions with uncertain outcomes. Throughout human history, we've altered the natural world in profound ways - redirecting rivers, transforming landscapes, moving species across continents, and changing the very composition of our atmosphere. Now, facing the consequences of these interventions, scientists and engineers are developing ever more ambitious technologies to address our ecological predicaments. From breeding heat-resistant coral to survive in warming oceans, to manipulating the genes of invasive species, to literally dimming the sun by injecting particles into the stratosphere - these "techno-fixes" represent a new chapter in humanity's relationship with nature. The book takes us on a global journey through laboratories, remote field sites, and government facilities where researchers are working on solutions that might either save us from disaster or lead us deeper into uncharted territory.

Chapter 1: Human Interventions: Engineering Rivers and Ecosystems

Humans have been reshaping rivers for millennia, but the scale and intensity of our interventions accelerated dramatically in the modern era. The Chicago River stands as a prime example of this engineering hubris. In the early 20th century, engineers performed an astonishing feat: they reversed the river's flow. Before this massive project, Chicago's waste flowed into Lake Michigan, contaminating the city's drinking water and causing deadly disease outbreaks. The solution was to dig a massive canal that would redirect the river's flow away from the lake, sending Chicago's sewage downstream toward the Mississippi River. This remarkable achievement solved Chicago's immediate public health crisis but created new problems downstream. The reversed river connected two previously separate watersheds - the Great Lakes and the Mississippi River basin - creating an artificial highway for invasive species to travel between these ecosystems. Today, engineers are deploying increasingly sophisticated technologies, including electrical barriers in the canal, to prevent Asian carp and other invasive species from moving between these waterways. The barriers essentially create an underwater electric fence designed to repel fish without impeding boat traffic or water flow. The story of the Chicago River illustrates a pattern repeated throughout the Anthropocene: our solutions to environmental problems often become environmental problems themselves. The electrical barriers are a response to a problem created by the river's reversal, which was itself a solution to pollution issues. This cascading sequence of interventions is characteristic of our new geological epoch, where humans have become the dominant force shaping natural systems. What makes these river engineering projects so significant is their scale and lasting impact. The reversal of the Chicago River wasn't merely a local infrastructure project - it fundamentally altered the hydrology of approximately two-thirds of the United States. Similarly, the control of the Mississippi River through levees and spillways has prevented natural flooding while simultaneously contributing to the rapid disappearance of Louisiana's coastal wetlands, which relied on regular floods to deposit sediment and counteract natural subsidence. These river engineering projects represent both human ingenuity and our tendency to underestimate the complexity of natural systems. Each intervention necessitates further interventions, creating an escalating cycle of control that extends far beyond the original problem's scope. As one engineer reflected, "If we want everything to remain as it is, everything must change" - a statement that captures the paradoxical logic of the Anthropocene, where maintaining stability requires constant technological innovation.

Chapter 2: The Louisiana Delta: Flood Control Paradox

The Mississippi Delta in Louisiana presents one of the most dramatic examples of unintended consequences from human engineering. For centuries, the Mississippi River would naturally flood its banks, depositing sediment that built and maintained the vast wetlands of southern Louisiana. When early settlers constructed levees to protect their communities from flooding, they inadvertently cut off this vital supply of sediment. The result is a land-loss crisis of staggering proportions: Louisiana has shrunk by more than 2,000 square miles since the 1930s, with a football field's worth of land disappearing every hour and a half. This predicament stems from the fundamental geology of delta formations. Delta lands naturally sink over time as soft sediments compact. Under natural conditions, regular river flooding would deposit new sediment, building land to counterbalance this subsidence. The elaborate system of levees, floodwalls, and spillways built to control the Mississippi has disrupted this balance, allowing natural subsidence to proceed without the compensating build-up of new land. The very system designed to protect Louisiana from the river is causing the state to disappear into the Gulf of Mexico. Faced with this existential threat, engineers are now planning what might be called "controlled crevasses" - massive gates in the levees that would allow carefully managed reintroduction of sediment-laden river water into adjacent wetlands. The largest of these projects, the Mid-Barataria Sediment Diversion, will cost $1.4 billion and is designed to create a controlled mini-delta. This represents a fascinating shift in approach: rather than fighting the river's natural tendency to deposit sediment, engineers are now trying to harness and direct this power. The Louisiana case demonstrates the complexity of managing natural systems over long timescales. The levees that seemed like a logical solution to flooding in the short term have proven catastrophic over decades. Now, new interventions like sediment diversions attempt to mimic natural processes while still maintaining human control. Yet these diversions will inevitably create their own suite of impacts, affecting fisheries, existing communities, and ecosystems in ways that cannot be fully predicted. Perhaps most poignantly, this crisis disproportionately affects vulnerable communities. Isle de Jean Charles, home to members of the Biloxi-Chitimacha-Choctaw Tribe, has lost 98% of its land area since the 1950s, forcing residents to relocate. These communities bear the consequences of engineering decisions they had little part in making. As one resident noted, watching his homeland erode away: "It's kind of hard to imagine that no one's going to be living here. But I've watched it erode away."

Chapter 3: Conservation Reliance: Saving Species We Nearly Destroyed

In the harsh Mojave Desert lies a remarkable story of persistence: the Devils Hole pupfish. These tiny blue fish, barely an inch long, survive in a single limestone cavern filled with 93°F water - the smallest natural range of any vertebrate on Earth. The pupfish represent an extreme example of a growing category called "conservation-reliant species" - creatures that can only survive with continuous human intervention because their habitats have been so severely compromised by human activities. The Devils Hole pupfish almost disappeared in the 1960s when nearby groundwater pumping caused water levels in their cavern to drop dramatically. After a legal battle that reached the Supreme Court, pumping was restricted, but the species remains perilously close to extinction. Today, fewer than 200 individuals exist, and scientists have constructed an elaborate $4.5 million replica of Devils Hole - a kind of fishy Westworld - to maintain a backup population. The facility employs full-time caretakers who monitor water chemistry, manage the food web, and even occasionally provide supplemental meals of brine shrimp. Conservation reliance represents a profound shift in how we think about preserving biodiversity. Traditional conservation aimed to protect wild places from human influence, allowing species to thrive independently. But in the Anthropocene, truly independent nature scarcely exists. Instead, biologists now find themselves actively managing endangered species through techniques like captive breeding, genetic rescue, predator control, habitat manipulation, and even hand-feeding. The goal is no longer to restore species to self-sufficiency but to prevent their extinction through perpetual care. This approach raises challenging questions about what we're actually conserving. When a species can only exist under intensive human management, what exactly are we preserving? The pupfish in their artificial tank are genetically identical to their wild relatives, but they experience a very different existence - protected from predators, with regulated water chemistry and controlled breeding. They represent something neither fully wild nor fully domesticated but rather a new category: the conservation-reliant species. The list of such species grows longer each year. The California condor, black-footed ferret, Kirtland's warbler, and hundreds of others now depend on human intervention for survival. Conservation biologist Phil Pister, who famously saved the last Owens pupfish population in two buckets, was often asked why he devoted his career to such seemingly insignificant creatures. His reply was pointed: "What good are pupfish?" people would ask. "What good are you?" Pister would respond. His question highlights the moral dimensions of conservation in the Anthropocene - do we have an obligation to save what we've imperiled, even if it requires perpetual intervention?

Chapter 4: Assisted Evolution: Designing Coral for Climate Change

Coral reefs face an existential threat from climate change. Rising ocean temperatures trigger coral bleaching - a phenomenon where corals expel their symbiotic algae and often die as a result. Global bleaching events have become increasingly frequent and severe, with the 2014-2017 event killing approximately half the corals on the Great Barrier Reef. Without intervention, most of the world's coral reefs could disappear within decades, taking with them some of the planet's most diverse ecosystems. In response to this crisis, marine biologist Ruth Gates pioneered a radical approach called "assisted evolution." Rather than simply protecting corals from human impacts, Gates proposed actively helping corals adapt to human-altered conditions. Her team identified corals that naturally survived bleaching events and selectively bred them, hoping to produce offspring with enhanced heat tolerance. They also experimented with exposing corals to gradually increasing temperatures in laboratories, essentially accelerating natural selection under controlled conditions. The process works somewhat like traditional animal or plant breeding. Just as humans have bred dogs for specific traits over generations, scientists are attempting to breed corals for heat resistance. However, there's a crucial difference: traditional breeding typically enhances traits humans find useful or appealing, while assisted evolution aims to help an organism survive in an environment we've inadvertently altered. The goal isn't to create "better" corals for human purposes but to help corals keep pace with rapid environmental change. This approach requires rethinking fundamental conservation principles. Traditional conservation focused on preserving natural systems by reducing human impacts. Assisted evolution, by contrast, embraces active human intervention in evolutionary processes. As Gates put it, "A lot of people want to go back to something. They think, if we just stop doing things, maybe the reef will come back to what it was." But she saw herself as a "futurist" who acknowledged that "a future is coming where nature is no longer fully natural." The ethical dimensions of this work are complex. Critics worry about unforeseen consequences of releasing engineered corals onto reefs. They question whether enhanced corals might outcompete naturally adapted species or disrupt ecological relationships that have evolved over millennia. Yet proponents argue that doing nothing ensures catastrophic reef loss. As Madeleine van Oppen, Gates's collaborator, explained: "We need to buy time. So I see assisted evolution as filling that gap, being a bridge between now and the day when we're really holding down climate change or, hopefully, reversing it."

Chapter 5: Gene Drives: Rewriting the Code of Wild Species

In a modest laboratory at the Australian Animal Health Laboratory, scientists are using CRISPR gene-editing technology to create what they call "detox toads." These are cane toads genetically modified to lack the toxic compounds that make them deadly to native Australian predators. This work represents a new frontier in addressing invasive species - using genetic engineering not just to alter domestic plants and animals but to deliberately modify wild populations. Cane toads were introduced to Australia in 1935 to control beetle pests in sugar cane fields. With no natural predators, they spread rapidly across northern Australia, causing ecological havoc as native animals that attempted to eat them died from their powerful toxins. Traditional control methods like physical removal have proven ineffective against an invader that can produce 30,000 eggs at a time. This seemingly intractable problem has led scientists to explore genetic solutions. The most revolutionary of these approaches involves "gene drives" - a genetic engineering technique that can rapidly spread specific traits through wild populations. Normally, genes have a 50% chance of being passed to offspring, but gene drives can increase those odds to nearly 100%. This creates a genetic cascade effect where an engineered trait could theoretically spread through an entire wild population within a few generations, even if that trait doesn't confer any survival advantage. For invasive species management, gene drives offer unprecedented possibilities. Scientists have proposed creating drives that would spread genes for reduced fertility or that would skew sex ratios toward males, potentially causing population crashes. One approach being developed for invasive mice would create "X-shredder" males whose sperm could only produce male offspring. Released into an island mouse population, these engineered males would father only sons, who would in turn father only sons, until eventually no females would remain and the population would collapse. The power of this technology raises profound questions about human intervention in nature. Gene drives could potentially eliminate disease vectors like malaria-carrying mosquitoes or eradicate invasive species from islands where they threaten endangered birds. Yet they could also spread beyond target populations or produce unexpected ecological side effects. The technology has been compared to Kurt Vonnegut's fictional ice-nine - a substance that could freeze all the water in the world. A single released organism carrying a gene drive could, theoretically, transform an entire species. Recognizing these risks, scientists are developing safeguards like drives designed to self-limit after a few generations or to work only in specific populations. Nevertheless, gene drives represent a watershed moment in human intervention in nature - a technology that doesn't just control individuals but rewrites the genetic future of entire wild species. As Australian gene-editing researcher Mark Tizard put it: "The classic thing people say with molecular biology is: Are you playing God? Well, no. We are using our understanding of biological processes to see if we can benefit a system that is in trauma."

Chapter 6: Carbon Capture: Turning CO2 into Stone

The accumulation of carbon dioxide in our atmosphere presents one of humanity's greatest challenges. Even if we drastically reduce emissions today, the CO2 already released will continue warming the planet for centuries. This reality has prompted scientists to explore technologies that can actually remove carbon dioxide from the air - a process known as carbon dioxide removal or negative emissions. In Iceland, a groundbreaking project demonstrates one promising approach. At the Hellisheiði Power Station near Reykjavík, a company called Climeworks has installed machines that extract CO2 directly from the ambient air. This captured carbon is then dissolved in water and pumped deep underground into basalt formations. Within two years, through natural chemical reactions with the surrounding rock, the carbon dioxide transforms from a gas into solid calcium carbonate - essentially turning into stone. As one engineer explained, "Rocks store CO2. They're actually one of the biggest reservoirs of carbon on earth. The idea is to imitate and accelerate this process to fight global climate change." This technology mimics and accelerates a natural process called chemical weathering, which would eventually lock away atmospheric carbon but would normally take hundreds of thousands of years. By speeding up this process, humans are attempting to undo some of the damage caused by rapidly releasing carbon that had been stored underground for millions of years as fossil fuels. In a sense, carbon capture represents humans deliberately reversing what has been their most consequential impact on the planet's systems. The challenge lies in scaling these technologies. Currently, carbon capture is expensive - Climeworks charges about $1,000 to remove and store a ton of CO2, while global emissions amount to roughly 40 billion tons annually. Physicist Klaus Lackner, a pioneer in the field, has calculated that to make a meaningful impact, we would need to deploy carbon capture on an industrial scale comparable to our fossil fuel infrastructure. This would require a massive global investment and technological deployment. Lackner suggests reframing how we think about carbon pollution. Rather than viewing emissions as a moral failing, we could treat carbon dioxide like any other waste product. "Rewarding people for going to the bathroom less would be nonsensical," he points out. Instead, we developed sewage systems to manage human waste. Similarly, we might develop carbon capture as a form of "carbon sewage treatment" - an essential service in an industrialized society. This approach doesn't diminish the urgent need to reduce emissions but acknowledges that some level of carbon cleanup will be necessary. Climate models increasingly incorporate negative emissions as essential for avoiding catastrophic warming. As one researcher put it: "We need to change the paradigm. Carbon dioxide should be regarded much the same way we look at sewage." This reimagining of our relationship with carbon represents both a technological challenge and a conceptual shift in how we understand human responsibility for planetary systems.

Chapter 7: Solar Geoengineering: Dimming the Sun to Cool Earth

When Mount Tambora erupted in Indonesia in 1815, it launched more than 100 million tons of gas and particles into the atmosphere. These materials blocked incoming sunlight, cooling the planet and causing what became known as "the year without a summer" - a period of failed harvests, famine, and strange weather across the Northern Hemisphere. This natural experiment in atmospheric modification has inspired a controversial climate intervention strategy: deliberately injecting particles into the stratosphere to reflect sunlight and cool the Earth. This approach, known as solar geoengineering or solar radiation management, would essentially create artificial volcanoes. Using high-altitude aircraft, engineers could spray sulfate particles or other reflective materials into the stratosphere, where they would remain suspended for years, forming a thin veil that would reflect a small percentage of incoming sunlight back to space. Models suggest that deploying such a system could potentially reduce global temperatures rapidly - unlike emissions reductions or carbon removal, which work much more slowly. The appeal of solar geoengineering lies in its relative simplicity and low cost. Researchers estimate that for perhaps $20 billion per decade - a fraction of what the world spends on fossil fuel subsidies - a fleet of specialized aircraft could deploy enough material to offset a significant portion of human-caused warming. This represents what Harvard physicist David Keith calls "the only way to do something fast" about climate change. As climate impacts accelerate and emissions remain high, this fast-acting option becomes increasingly tempting. Yet solar geoengineering presents profound risks and ethical dilemmas. Unlike carbon capture, which addresses the root cause of climate change, solar engineering merely masks warming while allowing carbon dioxide levels to rise. If a geoengineering program were started and then halted for any reason - war, economic collapse, or unintended side effects - the masked warming would manifest suddenly in what scientists call "termination shock," potentially causing rapid, catastrophic temperature increases. There are also concerns about altered rainfall patterns, reduced solar electricity generation, and visual changes to the sky itself, which models suggest would turn from blue to a whitish hue. Perhaps most troubling are the governance challenges. No international framework exists to regulate such interventions, yet their effects would be global. Who would decide whether to deploy such technologies, at what intensity, and for how long? As Harvard scientist Frank Keutsch explained: "If there's pressure from the public to do something fast, my concern is that there will be no tools at hand other than stratospheric geoengineering." This fear that desperation might drive deployment motivates many scientists to research the technology now, despite their misgivings about its use. Solar geoengineering represents the most extreme version of the paradox running throughout the book - using technological control to address problems created by previous technological interventions. As climate scientist Dan Schrag put it: "Geoengineering is not something to do lightly. The reason we're thinking about it is because the real world has dealt us a shitty hand."

Summary

Under a White Sky presents a crucial insight about our modern relationship with nature: as human impact on Earth's systems becomes increasingly dominant, our options narrow. We find ourselves in a recursive trap where we must apply ever more sophisticated technologies to address problems created by our previous technological interventions. This pattern reveals itself across diverse cases - from redirected rivers that require electric barriers to prevent invasive species migration, to coral reefs that might only survive through genetic assistance, to a climate so altered that we contemplate engineering the sky itself. Each solution spawns new problems requiring new solutions, creating an escalating cycle of control. This recursive dilemma raises profound questions about humanity's role on the planet. As we develop tools capable of manipulating everything from the genomes of wild species to the chemistry of the oceans and atmosphere, where do we draw the line between restoration and creation? The dividing line between natural and artificial has blurred beyond recognition. While traditional environmentalism often aimed to protect nature from human influence, the interventions described in the book acknowledge that such pure nature no longer exists. Instead, these projects represent a more pragmatic approach - using our technological powers to preserve what we can of biodiversity and climate stability, even if the resulting systems require perpetual management. What emerges is a sobering vision of our future relationship with the planet: not as passive stewards of natural systems, but as active managers of hybrid ecosystems that we have irreversibly transformed and upon which we ultimately depend.

About Author

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Elizabeth Kolbert

Elizabeth Kolbert is a staff writer at The New Yorker. She is the author of Field Notes from a Catastrophe: Man, Nature, and Climate Change and The Sixth Extinction: An Unnatural History. She lives in Williamstown, Massachusetts, with her husband and children.

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