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Themes
Key
LitCharts assigns a color and icon to each theme in The Uninhabitable Earth, which you can use to track the themes throughout the work.
Cascades, Systems Crises, and Interconnectedness
Human Responsibility and the Natural World
Optimism and Action vs. Despair and Nihilism
The Effects of Climate Change on Humanity
Summary
Analysis
Though humans have long tended to see the ocean as unfathomable and mysterious, ocean makes up 70 percent of the earth’s surface. The oceans play an important role in feeding people, regulating seasons, and modulating the planet’s temperature by absorbing the sun’s heat. But warming poses a serious threat to all of these functions. With fish populations migrating north and ocean waters acidizing as they absorb excess carbon dioxide, the ocean is becoming another factor in adding degrees of warming to the earth.
This passage significantly underscores the deeply symbiotic relationship between the human world and the natural one. Humans depend on the ocean for food—but the ocean’s health is at the mercy of the patterns of human industry. As humans pollute the world, the ocean becomes yet another complex feedback loop. The processes that normally cool the planet and keep the atmosphere clean invert and become agents of further warming.
Themes
Mass bleaching events, which have already decimated a huge percentage of reefs, including the famous Great Barrier Reef in Australia, will threaten 90 percent of all reefs by 2030. Reefs support a quarter of marine life, supplying food and income for hundreds of millions of people around the globe. In acidic waters, the fish, bivalves, and crustaceans that feed the world will no longer be able to thrive.
The ocean is a complex system in and of itself, and each of the world’s oceans is a part of the larger planetary-wide system of warming and weather. Here, the book telescopes all the way down to look at the microorganisms and small ocean creatures whose existences are threatened by the erasure of coral reefs. In doing so, the book shows that every seemingly inconsequential cog in the larger machine of our planet’s ecosystem is, in fact, vital. As these small microcosms break down, the whole system begins to cascade into chaos.
Themes
Between reef die-offs and the de-oxygenation of huge swaths of ocean, humanity is entering a period of mass extinction. The ocean is suffocating, and, in the process, releasing noxious chemicals such as hydrogen sulfide into the atmosphere, triggering feedback loops that will be difficult, at the least, to recover from.
The ocean can only hold so many chemicals, but as it releases them into the atmosphere to save itself, it jeopardizes other parts of the climate. This passage yet again illustrates just how deeply interconnected all of our climate systems are—and just how much is threatened when the effects of warming create chain reactions and cascades of more pollutants.
Themes
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The Gulf Stream and other major currents regulate regional temperatures, but in a warming and dying ocean, these paths may be interrupted, leading to a huge disruption in the planet’s equilibrium and weather systems. Though this may not happen on a human timescale, the Gulf Stream’s velocity is decreasing noticeably—and the ocean’s transformation is reaching a dangerous tipping point.
Nature and humanity are at one another’s mercy. As human industry changes the ocean’s feedback responses to increased pollution and excess freshwater, the ocean threatens to compound other sources of warming and heat the planet even faster. Humanity’s refusal to pay attention to these cascades means that we are approaching our “tipping point” with more velocity each day.
Themes
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