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Reflections on Climate as Keyword and Shape-Shifting Noun

What does “climate” mean? Professor Jim Fleming argues that it deserves to be a keyword in the vocabulary of culture and society.

Climate Is a Keyword

“Climate” has long been one of the most consequential words in widespread usage. It deserves to be a keyword in the vocabulary of culture and society. Yet we find it neither in Raymond Williams’s classic volume Keywords: A Vocabulary of Culture and Society (1976) nor in Digital Keywords (2016), a recent update edited by Benjamin Peters.1 It is arguably one of the most linguistically complicated words, in part because of its roots in antiquity and its development over time, and also due to its growing relevance and entanglement with human affairs. Like all powerful ideas, climate can be deceptively simple to define, yet is subject to many cultural meanings and technical interpretations.2

Climate Is Shape-Shifting

It may be a truism for historians that anything that can be named possessed different meanings in different eras. Climate is a historically shape-shifting concept whose meaning has changed and is changing, perhaps faster than the climate itself. In these reflections, I review the changing nature of ideas about climate from antiquity to the present, adding a temporal dimension to the science and philosophy of climate change and the ways we think about it.

Climate Is Local

Climate—from the Greek term klima, meaning slope or inclination—was originally thought to depend only on the sun’s height above the horizon, a function of latitude. A second tradition, traceable to Aristotle, linked air and thus climate quality to a country’s vapors and exhalations. The Hippocratic tradition further linked climate to health and national character. Early climatologists were plant biologists and geographers who described climate zones by what grew within them.

Climate Is Agricultural

Traditionally, farmers kept a close watch on the weather, knew their local seasons, and prepared for changes. To everything there is a season—a time to sow and a time to reap, a time of abundance and a time of want. Scientific agriculturalists codified this knowledge into intricate hardiness maps and identified plant species for each growing region. With farming as the foundation of the state economies, national weather and climate services were sponsored by departments of agriculture, in the United States from 1890 to 1940. Now that growing seasons are changing, climate’s relation to agriculture is more important than ever.

Climate Is Commercial and Industrial

Since 1940 the National Atmospheric and Oceanic Administration (NOAA) and its predecessors have been run by the US Department of Commerce—for the benefit of commerce. The goal is a “weather-ready nation” that is optimally adaptive to its environment and responsive to environmental disruptions. With more people than ever living in cities, society is also more weather-sensitive than ever before. The field of “technoclimatology”3 involves the influences of climate on the technological aspects of modern living, not only in the quotidian sense of everyday life but also in the applicability of climatic information to engineering and the effects of climate on health, commerce, and industry.

Climate Is Average Weather

Climate is often said to be a statistical index of averaged weather phenomena across space and time, the sum total of which characterizes the condition of the atmosphere at any one place on the earth’s surface in a specified epoch. According to this definition, climate is concerned with the average states of weather and the frequency of the different individual types of weather in their geographical distribution.

Climate Is Changing

In the 19th century, scientists learned that climatic conditions can deviate dramatically from the average, for example during the last ice age, when the temperature was about 18˚F cooler than today and glaciers covered Manhattan. The identification of a mechanism for climate’s cosmic changes, from glacial to interglacial—from ice to heat—remains a central concern for geologists, astronomers, and cosmic physicists and chemists. It is a planetary issue that remains open to new approaches and ideas.

Climate Is Digital

In 1955 the meteorologist Norman Phillips used the most advanced digital computer available to prepare a numerical simulation of the general circulation of the atmosphere. His results—patterns of trade winds, westerly winds, moving cyclones, and strong jet streams—were suggestive but incomplete. If this was possible, what then was not possible? Since then, most climate science has been based on the output of computer models, with reduced emphasis on direct observation and measurement. Imposing challenges remain, including understanding the influence of clouds, aerosols, water vapor, and other complex factors. Although models are improving, they do not predict future climate conditions.

Climate Is Driven

During the International Geophysical Year of 1957–58—and motivated by the earlier work of Guy Callendar and others—Charles Keeling began a lengthy time series of accurate measurements of the atmosphere’s carbon dioxide content. Since then, the Keeling curve, the famous saw-toothed curve of rising CO2 concentrations, has become the environmental icon of the contemporary world. The anthropogenic origins of the increase and the gradual warming trend of recent decades have placed CO2 squarely at the center of climate concerns.

Climate Is Chaotic

In 1960, just as atmospheric scientists were gaining confidence that satellite observations, digital computers, and a host of other new tools would cut, if not unravel, their Gordian knot of complexity, Edward Lorenz introduced chaos theory into meteorology and, by extension, into climate modeling. He brought the novel understanding that chaos theory revealed an extreme sensitivity to initial conditions in a dynamical system of deterministic nonperiodic flow. In chaos theory, future states of the weather and climate become identifiable with the attractor of the dynamical system—but the dynamical system may have more than one attractor! Even given the development of more extensive measurements and ever more sophisticated technology, chaos theory holds that perfectly accurate forecasts of weather and climate will never be possible.4

Climate Change Is Disruptive

The carbon-dioxide-as-thermostat theory is the basis for the “anthropogenic greenhouse effect,” a concept later referred to as global warming and, more recently, climate disruption. Climate change has become a defining issue of our time—an existential threat to our species and to the planet itself. According to a broad international consensus, the defining moment to do something about it is right now. There is still time to tackle climate change, but doing so will require an unprecedented effort from all sectors of society.

Climate Is Symptomatic

In recent years, leading figures in the climate modeling community have called themselves “planetary physicians” and have appropriated descriptive metaphors from medical practice. Earth is sick and needs to see a doctor. It is out of balance, running a “fever” of 1 degree or more compared to a century ago, and the prognosis is not good. The fever will likely worsen substantially in the century to come, leading to melting ice caps, rising sea levels, killer heatwaves, and stronger storms. Most humans, by adding to the greenhouse effect, are morally culpable through their overconsumption and addiction to fossil fuels. The planetary physicians recommend drastic lifestyle changes such as a strict carbon “diet” and other mitigation strategies such as the use of renewable energy sources and efforts toward stringent energy efficiency so as to stabilize the amount of carbon dioxide in the atmosphere and avoid the most dangerous climatic consequences. Compliance with this advice, however, will involve the entire population of Earth and will likely necessitate the complete restructuring of policies and even polities worldwide.

Climate Intervention Is Barking Mad

Engineers on the fringe of climate science advocate for an invasive form of planetary surgery called geoengineering—or, more accurately, climate intervention.5 They are proposing heavy-handed interventions to “fix the sky.”6 Climate intervention is no longer a merely rhetorical phrase. Its advocates are currently seeking respectability within national and international environmental policy circles. Their speculative ideas include diminishing the sun’s influence on the climate system by shooting as much as a million tons of highly reflective sulfate aerosols into the stratosphere to turn the blue sky milky white, launching a huge fleet of space mirrors to divert incoming solar radiation, and making marine clouds thicker and more reflective by whipping ocean water into a froth with giant pumps that act like egg beaters. Remember, though, that control of a complex and chaotic climate system is simply not possible.

Carbon-Cycle Engineering—What Could Possibly Go Wrong?

Teams of scientists and engineers (and a few social scientists and humanists) are calling for scientifically validated, technically feasible, and societally sensitive means to remove and safely store significant amounts of atmospheric CO2. Their goal is to limit global warming to under 2˚C by 2100.7 Negative Emissions Technologies (NETs), intended to store more carbon than they consume, do not currently exist but are imagined as massive engineering projects—planetary-scale interventions in Earth’s carbon cycle. NETs are engineers’ dreams. Their monitoring and verification requirements would be immense and unprecedented in scale. These technological fixes would attempt to use engineering or technology to solve problems, even societal problems. However, by focusing on technical challenges and deemphasizing societal perspectives, such “solutionism” appears to be shortsighted, often temporary, and rather gear-headed. A short list of engineering proposals includes the following: the removal and sequestering of terrestrial carbon by new afforestation and agricultural practices—but arable lands are limited, food production comes first, and biodiversity and water supplies could be threatened. Bioenergy with carbon capture and sequestration (BCCS) is an appealing idea involving the burning and reuse of all available plant waste—but this is logistically challenging and not currently scalable to planetary levels. Coastal blue carbon involves stimulating the growth of plants and the deposition of carbon-rich sediments in coastal zones—but with unquantified and possibly unimagined ecological damage in valuable and highly sensitive areas. Direct air capture and sequestration, currently feasible only on small scales using “artificial trees,” is energy intensive and very, very expensive. The mining industry imagines exposing what they call “waste rock” to accelerated weathering and carbon mineralization, with unknown negative impacts to the landscape, especially water supplies. NETs should be viewed as high-tech supplements to mitigation, energy efficiency, renewables, fuel-switching, and adaptation strategies. They are expensive and energy- and infrastructure-intensive, requiring huge investments and an estimated 30 percent expansion of world energy use.8 NETs are at vastly different stages of readiness, ranging from speculative proposals to small-scale implementation. The champions of these techniques are seeking patents and future profitability, yet it is increasingly clear that proprietary solutions for planetary problems will not work.

The Current Situation

The growing problem of changing environmental conditions caused by climate destabilization is well recognized as one of the defining issues of our time. The root problem is greenhouse gas emissions, and the fundamental solution is the curbing of those emissions. Climate engineering has often been considered to be a “last-ditch” response to climate change, to be used only if the damage from climate change produces extreme hardship, although the likelihood of eventually needing to resort to these efforts grows with every year of inaction on emissions control. The National Academies recently concluded that there is a lack of information on potential interventions in the climate system, whether by albedo modification or carbon dioxide removal and reliable storage. They further concluded that climate intervention is no substitute for the reduction of carbon dioxide emissions and adaptation to the negative consequences of climate change.

What is to be done? I argue that discussion and decision-making regarding climate intervention and carbon-cycle engineering requires new and improved climate science, including continuous, technologically enhanced, real-time measurement and monitoring of the atmosphere at every scale sufficient to provide feedback and diagnostics for improved models. We also need to encompass both interdisciplinary and humanistically informed critical perspectives involving a broad and inclusive array of international and intergenerational participants. In fact, the field’s current lack of diversity indicates that some of the most important questions have probably not even been posed. For example, what gendered, racial, or class-based assumptions inform the field? How will climate change and climate engineering alter fundamental human relationships with nature? How is climate engineering perceived in different cultures? Who will make decisions on behalf of the planet? Certain questions reveal the shortcomings of economic analysis: How should “losers” be compensated and how would any non-market goods, which may be irreplaceable, be valued? Is this even the right framing? Joni Mitchell was right: “We really don’t know clouds [or climate or the carbon cycle] at all.” How can we wrest the future of the planet from the hands of potentially dangerous demagogues or climate engineers? We can begin by confronting the paucity of their proposals without throwing cold water on the vast challenges that lie before us.

  1. Raymond Williams, Keywords: A Vocabulary of Culture and Society (New York: Oxford University Press, 1976); Benjamin Peters, ed., Digital Keywords: A Vocabulary of Information Society and Culture (Princeton, NJ: Princeton University Press, 2016).
  2. Mike Hulme, “Climate Change (concept of),” in International Encyclopedia of Geography (Hoboken, NJ: Wiley-Blackwell, 2015).
  3. Helmut Landsberg, Physical Climatology, 2nd ed. (State College, PA: Gray Publishing, 1964), 389.
  4. For Lorenz and chaos theory, see Edward Lorenz, The Essence of Chaos (Seattle: University of Washington Press, 1993).
  5. US National Academies of Sciences, Engineering, and Medicine, Climate Intervention, 2 vols. Reflecting Sunlight to Cool Earth and Carbon Dioxide Removal and Reliable Sequestration (Washington, DC: National Academies Press, 2015); US National Academies of Sciences, Engineering, and Medicine, Negative Emissions Technologies and Reliable Sequestration: A Research Agenda (Washington, DC: National Academies Press, 2019).
  6. James Fleming, Fixing the Sky: The Checkered History of Weather and Climate Control (New York: Columbia University Press, 2010).
  7. Daniel Klein et al., eds., The Paris Agreement on Climate Change: Analysis and Commentary (New York: Oxford University Press, 2017).
  8. Ferenc L. Toth, ed., “Geological Disposal of Carbon Dioxide and Radioactive Waste: A Comparative Assessment,” Advances in Global Change Research 44 (2011).


Jim Fleming

Jim Fleming is the Charles A. Dana Professor of Science, Technology, and Society at Colby College. His books include Meteorology in America (Johns Hopkins, 1990), Historical Perspectives on Climate Change (Oxford, 1998), The Callendar Effect (AMS Books, 2007), Fixing the Sky (Columbia, 2010), and Inventing Atmospheric Science (MIT, 2016).


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