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The Long Thaw

The Long Thaw: How Humans Are Changing the Next 100,000 Years of Earth's Climate

Copyright Date: 2009
Pages: 192
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    The Long Thaw
    Book Description:

    If you think that global warming means slightly hotter weather and a modest rise in sea levels that will persist only so long as fossil fuels hold out (or until we decide to stop burning them), think again. InThe Long Thaw, David Archer, one of the world's leading climatologists, predicts that if we continue to emit carbon dioxide we may eventually cancel the next ice age and raise the oceans by 50 meters. The great ice sheets in Antarctica and Greenland may take more than a century to melt, and the overall change in sea level will be one hundred times what is forecast for 2100. By comparing the global warming projection for the next century to natural climate changes of the distant past, and then looking into the future far beyond the usual scientific and political horizon of the year 2100, Archer reveals the hard truths of the long-term climate forecast.

    Archer shows how just a few centuries of fossil-fuel use will cause not only a climate storm that will last a few hundred years, but dramatic climate changes that will last thousands. Carbon dioxide emitted today will be a problem for millennia. For the first time, humans have become major players in shaping the long-term climate. In fact, a planetwide thaw driven by humans has already begun. But despite the seriousness of the situation, Archer argues that it is still not too late to avert dangerous climate change--if humans can find a way to cooperate as never before.

    Revealing why carbon dioxide may be an even worse gamble in the long run than in the short, this compelling and critically important book brings the best long-term climate science to a general audience for the first time.

    eISBN: 978-1-4008-2876-0
    Subjects: Physics, Ecology & Evolutionary Biology, Geology

Table of Contents

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  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-x)
  3. Acknowledgments
    (pp. xi-xii)
  4. PROLOGUE. Global Warming in Geologic Time
    (pp. 1-12)

    Global warming could be one of humankind’s longest lasting legacies. The climatic impacts of releasing fossil fuel CO₂ to the atmosphere will last longer than Stonehenge. Longer than time capsules, longer than nuclear waste, far longer than the age of human civilization so far. Each ton of coal that we burn leaves CO₂ gas in the atmosphere. The CO₂ coming from a quarter of that ton will still be affecting the climate one thousand years from now, at the start of the next millennium. And that is only the beginning.

    The excess CO₂ in the atmosphere at the next millennium...


    • CHAPTER 1 The Greenhouse Effect
      (pp. 15-29)

      The global warming forecast is not new, nor has it changed much over the last century. The basic physics of the greenhouse effect was described in 1827 by Jean Baptiste Joseph Fourier. Fourier was a mathematician in Bonaparte’s army in Egypt. His name is best known for the Fourier transform, a mathematical technique for separating some complicated signal (such as the history of temperature through time, to choose an apropos example) into the sum of simple waves of different frequencies (such as the day/night cycle and the annual cycle), what we call calculating a spectrum.

      Fourier’s contribution to Earth science...

    • CHAPTER 2 We've Seen It with Our Own Eyes
      (pp. 30-44)

      Thermometers have been around in something like their modern form since the first mercury thermometer of Gabriel Fahrenheit, in 1724. There are many stories about the origin of the Fahrenheit temperature scale, but one is simply that 0⁰F was the coldest temperature that Fahrenheit experienced in the winter of 1708–1709, and 100⁰F was his own body temperature. The scale puts the melting and boiling points of water at the somewhat awkward temperatures of 32⁰F and 212⁰F, respectively. We in the United States tend to think of the metric system as some newfangled thing, but the Celsius scale is no...

    • CHAPTER 3 Forecast of the Century
      (pp. 45-54)

      Before we venture out into deep time, let’s look in on the forecast for the next one hundred years. Our interest is not totally selfish; a lot of the action will actually take place on timescales of centuries.

      The fossil fuel era could potentially last until about the year 2300, when coal begins to run out. After the CO₂ is released to the atmosphere, it takes a few hundred years, perhaps a thousand, for the CO₂ to dissolve in the ocean, as much as is going to. The atmospheric CO₂ concentration will spike upward and relax back downward, on a...


    • CHAPTER 4 Millennial Climate Cycles
      (pp. 57-68)

      One way to get a handle on the scale of the global warming forecast is to compare it with natural climate changes in the past. Climate varies naturally, for several different reasons that tend to act on different timescales. In this chapter, we will consider natural climate changes of about a thousand years’ duration, and in the two chapters after that, climate changes on successively longer timescales, ultimately reaching millions of years in Chapter 6. Chapter 7 puts everything back together again, to compare climate changes in the past to those that are forecast for the future.

      The first meteorological...

    • CHAPTER 5 Glacial Climate Cycles
      (pp. 69-77)

      The discovery of the glacial cycles was a slick piece of detective work. Earth scientists two centuries ago were not professionals in the modern sense. They were not motivated by publishor-perish rules at universities, or competition for research grant money. Many were gentlemen of privilege, or quirky devoted amateurs, with the determination to indulge a passion of choice, in this case an interest in the history of the Earth.

      Here’s the case. The mountains in Switzerland are scattered with rocks called exotics, large rocks that once broke off from bedrock hundreds of kilometers away. The question is, how did the...

    • CHAPTER 6 Geologic Climate Cycles
      (pp. 78-90)

      In this chapter we are going to zoom out even further in time. Over millions of years, the climate of the Earth changes in different sorts of ways, with different sorts of patterns, than we have seen so far. The climate of the last 35 million years includes ice sheets: large and permanently frozen, holding significant amounts of water. Before this time, for millions of years, there were no ice sheets at all.

      A time period such as today, with permanent ice sheets somewhere on Earth, will be referred to as a “great ice age.” Within our current great ice...

    • CHAPTER 7 The Present in the Bosom of the Past
      (pp. 91-98)

      The first question many people ask about the issue of human-induced climate change is how the forecast stacks up against natural variability and cycles in climate. Is global warming something big, or is it just nature-as-usual for the Earth? That question can now be answered by comparing the global warming forecast from Chapter 3 with past climate variations described in Chapters 4, 5, and 6. Even if you glazed over some of the marvelous details in those chapters, you should be able to jump back in here, reading this chapter as a sort of summary.

      The impression I have is...


    • CHAPTER 8 The Fate of Fossil Fuel CO₂
      (pp. 101-113)

      We would never have imagined life on Earth if we hadn’t seen it for ourselves. The intrepid heroes on the TV show Star Trek occasionally encountered sentient beings composed entirely of energy, rather than carbon. Such beings would never have predicted the magic of carbon on Earth from first principles, or at least from the first principles of science that we have discovered so far.

      A tiny fraction of the carbon on Earth is living carbon. If the living carbon on Earth were smeared out over the entire surface of the Earth (a grisly thought) it would be just a...

    • CHAPTER 9 Acidifying the Ocean
      (pp. 114-124)

      CO₂ is an acid, with which humankind is acidifying the oceans. In response, CaCO₃ (a base) will dissolve on land and in the ocean, restoring the pH balance of the ocean. This process will take thousands of years. As the pH of the ocean recovers, the change in ocean chemistry will extract some of the fossil fuel CO₂ from the atmosphere, but even after the pH recovery is complete, models of the carbon cycle predict that about 10% of the fossil fuel CO₂ will remain in the atmosphere, until it is consumed by the weathering thermostat, which stabilizes the climate...

    • CHAPTER 10 Carbon Cycle Feedbacks
      (pp. 125-136)

      The carbon cycle as presented in Chapters 8 and 9 generally has a calming influence on climate. The ocean takes up most of the fossil fuel CO₂ in a few centuries, leaving some behind, in a fairly well-behaved, predictable way. Our only complaint was that the carbon cycle was so slow to clean up the mess.

      The carbon cycle from the real world, as documented in ice cores and other climate records, seems to have had a different temperament. Instead of moderating the climate changes that were driven by orbital variations, the carbon cycle seems to fan the flames of...

    • CHAPTER 11 Sea Level in the Deep Future
      (pp. 137-148)

      The most compelling reason to worry about sea level rise in the future comes from sea level estimates from the past. Ancient coral reefs and relic beach deposits attest to large changes in the sea level associated with past climate changes. Periods of low sea level, such as the last glacial maximum, are more difficult to document in this way because the relic seashore is now submerged under more than a hundred meters of water. In some locations such as Barbados, the land surface itself is rising out of the ocean faster than the flooding of the ocean, leaving the...

    • CHAPTER 12 Orbits, CO₂, and the Next Ice Age
      (pp. 149-157)

      Two centuries ago, climatologists were more concerned about the next ice age than they were about global warming. Svante Arrhenius, who first estimated the climate sensitivity to atmospheric CO₂ in 1896, was interested in explaining the cause of the last ice age. From moraines it was known that the landscape had undergone repeated assault from massive ice sheets. The timing was not known very well, because moraines are difficult to date, especially without carbon-14 dating, and they document only the coldest times, while the warmest times that we’re interested in, the interglacials, leave no trace. So the landscape offered no...

  8. EPILOGUE. Carbon Economics and Ethics
    (pp. 158-174)

    Humankind has the potential to alter the climate of the Earth for hundreds of thousands of years into the future. That I feel can be said fairly confidently. But will we? Do social inertia, energy infrastructure, and sheer numbers of people on Earth make the business-as-usual global warming forecast inevitable, or is global warming something that can be avoided? This is much harder to predict. Technologically I believe that it is possible to avoid dangerous climate change, if we so choose. But making a decision: there’s the tricky part. Climate change is a global issue that ramps up slowly and...

  9. Further Reading
    (pp. 175-178)
  10. Index
    (pp. 179-180)