In 2001, the world was told not to worry about environmental problems. The message came from an unexpected source: Bjørn Lomborg, a political scientist who was virtually unknown outside his native Denmark. His book The Skeptical Environmentalist became a lightning rod in debates over climate and environmental policy.Footnote 1 While it was embraced in political and media circles for challenging environmental alarmism, it drew fierce criticism from scientists, who accused Lomborg of misusing data and distorting established research. Leading journals published rebuttals, and Denmark’s scientific authorities formally reviewed the book, concluding that it lacked scientific credibility. Yet the controversy only amplified Lomborg’s public profile, and the book’s notoriety as flawed science became inseparable from its influence. It became an instant best seller and ultimately established him as one of the world’s most prominent critics of mainstream environmental policy.
Since then Lomborg has become a globe-trotting public intellectual, tirelessly contributing to debates about how to improve global welfare most efficiently and how to save the world from climate change. He has received multiple accolades doing this, being selected by the World Economic Forum as a Global Leader for Tomorrow in 2001 and featuring on the Time Top 100 list of the world’s most influential people in 2004, and in 2008 Esquire named him one of the seventy-five most influential people of the twenty-first century so far. Lomborg’s main institutional platform is the American-based think tank Copenhagen Consensus Center (CCC), which “researches the smartest solutions for the world’s biggest problems” and advises “policy-makers and philanthropists how to spend their money most effectively.”Footnote 2
Lomborg’s message has been especially well received in the world of American conservative media, business, think tanks, and politics. He has been a frequent guest at Fox News, as well as on the conservative YouTube channels of Ben Shapiro, Joe Rogan, and Jordan B. Peterson. He has been an affiliate of the Hoover Institute, received funding from the billionaire Paul Singer, and is an advisory board member of the Alliance for Responsible Citizenship—a group cofounded by Jordan Peterson including several high-profile climate deniers. But Lomborg’s efforts have also been bolstered by support from Nobel Prize-winning economists, by invitations from figures like Bill Gates to discuss global challenges, and by his prolific contributions to major media platforms such as Project Syndicate.Footnote 3 Altogether, even if he is less prominent today than a decade ago, Lomborg has arguably been one of the most influential voices in environmental debates in the first decades of the twenty-first century
The aim of this article is to place Lomborg in these debates. Our starting point is a view of the history of environmental debates as a long-standing contest between two radically different ideas about the impact of human activities on nature and the relation between humankind and its natural environment. Since at least the eighteenth century, this contest has been fought out between threatening visions of natural limits, scarcity and constraint on the one hand, and a promethean argument for continued abundance, expansion and exploitation which stresses that human ingenuity will overcome all societal problems on the other.Footnote 4 When the modern environmental movement arose in the 1960s, it reignited this long-standing debate by stressing the issues of resource scarcity and overpopulation. The movement’s sweeping attack on the postwar discourse of endless economic growth quickly stirred the defenders of capitalism to rekindle a promethean confidence in the ability of humans to solve all potential problems.Footnote 5
One of the most prominent defenders of the promethean creed in the 1970s and 1980s was the American economist Julian Simon. A professor of business administration at the University of Maryland, Simon gained fame for his portrayals of the human mind as “the ultimate resource” and for his claim that more people would mean more abundance, as humans kept developing new resources and technologies to innovate themselves out of scarcity.Footnote 6 For Simon, it was imperative, however, that people were left free to do so, arguing against government intervention, and stressing the role of the free market.
Simon’s market-based prometheanism gained considerable traction in the 1980s and still has many followers. Yet the singular belief in the market’s ablity to fix environmental challenges has arguably become more marginal in recent years, as climate change has taken the headlines in political debates. As observed by political theorist John S. Dryzek, these debates have seen the arrival of a new form of prometheanism, which still celebrates the boundless fountain of human ingenuity, but asserts that countering the issue of climate change requires large-scale state investment and involvement. Bjørn Lomborg, Dryzek notes, is one of the most prominent proponents of this new prometheanism and has thus succeeded Simon as the new “public face of prometheanism.”Footnote 7
In contrast to Simon, however, Lomborg argues that it is necessary to address environmental problems such as climate change through public policies.Footnote 8 Yet he still downplays the threat it represents and argues against implementing drastic political measures to reduce emissions, as it would be more economically justifiable to spend money on other societal problems. Instead of comprehensive regulatory policies, Lomborg advocates fighting climate change through massive public and private investment in R & D, specifically focusing on developing new large-scale technologies such as geoengineering. Accordingly, as Dryzek suggests, Lomborg’s prometheanism entails vacating Simon’s belief in self-correcting markets and replacing it with a more activist view on policy, research, and markets.Footnote 9
Elaborating on Dryzek’s observations, we argue that Lomborg represents a broader shift from a “market” to a “planning” orientation within promethean discourse.Footnote 10 This is a shift that can be found in politics, the think tank sphere, and organized business interests, but also in academia, not least in economics. For example, Lomborg’s planning prometheanism shares many traits with the ecomodernist tradition, which has also gained prominence in recent years.Footnote 11 Moreover, Lomborg’s core arguments—such as his emphasis on cost–benefit analysis, technological optimism, and prioritizing economic development over aggressive climate action—are echoed by policymakers, business leaders, and commentators, helping to shape and influence mainstream debates about the practicality and priorities of environmental policy.
Although the planning orientation has become central to promethean discourse, it has been given scant attention by historians.Footnote 12 This is also the case with Lomborg’s work and activities. While many have criticized Lomborg’s notoriously selective and flawed use of scientific research, none have provided an analysis of his contribution to environmentalist debates from the perspective of intellectual history.Footnote 13
Rather than simply addressing a gap in existing historiography on Lomborg, this article uses his work as a prism to illuminate a broader shift from market to planning in promethean discourse. Situating Bjørn Lomborg in the history of climate politics and contemporary prometheanism, we ask the following questions. What are the main intellectual sources of inspiration for Lomborg’s planning prometheanism? How can we understand its ideological implications? How does it relate to earlier iterations of prometheanism and what can it tell us about the evolution of this discourse in a longer historical perspective?
The article makes three central arguments. The first is that Lomborg’s version of planning prometheanism was a synthesis of ideas drawn from three distinct American economists. Building on Julian Simon’s firm belief in human ingenuity as a solution to global challenges, Lomborg, however, adopted a more proactive stance by incorporating cost–benefit analysis and technological solutions, drawing on the ideas of climate economist William Nordhaus and game theorist Thomas Schelling. This approach enabled Lomborg to frame climate change as just one of many societal challenges to prioritize when allocating resources for a better world, while simultaneously advocating for increased economic growth, government-led R & D, and the development of new technologies as key solutions to global warming.
The second argument concerns the ideological commitments of Lomborg’s work. Although Lomborg claims that his work serves a democratic function by providing the public with the best information on environmental issues, we argue that his approach is rooted in a technocratic ethos and a deep skepticism of democracy, stemming from his reliance on rational-choice theory. The third argument situates planning prometheanism within a broader historical context. We argue that Lomborg’s focus on R & D and geoengineering represents a revival of mid-twentieth-century promethean confidence in science and technology as tools for reshaping both society and the natural world, a hallmark of promethean thought during the 1950s.
Against this background, the article presents prometheanism as an evolving mode of thought, continuously adapted to address new societal challenges and trends, as its advocates creatively appropriate and merge elements from diverse and sometimes conflicting discourses. Indeed, as we will return to, while prometheanism flourished during the neoliberal era, it has been evolving into a form well suited to thriving not only in a post-neoliberal context, but presumably also in a new Trumpian political landscape.
Becoming a skeptical environmentalist: the influence of Julian Simon
Bjørn Lomborg studied political science at Aarhus University in the late 1980s and, after completing a Ph.D. in game theory at the University of Copenhagen, returned to Aarhus, where he received tenure in 1997. His path to prometheanism followed in Julian Simon’s footsteps. In the preface to The Skeptical Environmentalist, Lomborg recalls that the idea for the book first took shape in 1997, when he came across an interview with Julian Simon in an issue of Wired magazine while browsing a bookstore in Los Angeles.Footnote 14 Simon had achieved fame and notoriety through a bet he made in 1980 (and eventually won) against celebrity biologist and “neo-Malthusian” environmentalist Paul Ehrlich about the future price of five metals. In combination with the publication of his massively popular book The Ultimate Resource in 1981, this victory gained Simon a reputation as “the doomslayer.”Footnote 15
The context of Simon’s intervention was the growing concerns in the late 1960s and early 1970s that the economic growth of the advanced industrial countries could not continue without severe environmental degradation. These concerns centered on resource scarcity, which was linked to the fastest rates of population and economic growth that the world had ever seen, which in turn resulted in various forms of pollution that threatened the ecosystem. These concerns had been voiced since 1945 but reached a new peak with the publication of Paul Ehrlich’s book The Population Bomb in 1968 and the Limits to Growth report in 1972.Footnote 16
In answering these concerns, Simon reactivated, and added to, the promethean belief in the human capacity to overcome any limit to societal progress, growth, and abundance through mastery of nature. According to historian Troy Vettese, Simon’s intellectual framework was itself not original but assembled discursive features from recent advances within demographic studies, the canon of twentieth-century prometheanism, and Hayekian epistemology into a novel attack on the neo-Malthusian advance.Footnote 17 Inspired by revisionist demographic studies by Esther Boserup, Richard Easterlin, and Simon Kuznets, Simon argued that there is no correlation between environmental decline and economic growth. From institutional economist Erich Zimmermann’s book World Resources and Industries (1933), he took the idea that resources are constructed by human ingenuity and market pressures, rather than simply found in nature. Finally, his idea that commodity prices empirically refuted the problem of resource scarcity drew on Scarcity and Growth: The Economics of Natural Resource Availability (1963), a study written by the economists Harold J. Bennett and Chandler Morse and sponsored by the Resources for the Future think tank. As Vettese argues, the unique feature that Simon added to twentieth-century promethean thought was a firm conviction that markets can solve all resource and pollution problems through the price mechanism, which would encourage people to allocate resources to where they are most valued and to find and develop new resources and technologies according to price pressure. Moreover, Simon also differed from his immediate sources of inspiration in his efforts to disseminate his arguments beyond the academy and into the public sphere—often in a highly polemical fashion.
This can be gleaned by the aforementioned 1997 interview with Simon in Wired magazine in 1997.Footnote 18 In the interview, entitled “The Doomslayer,” Simon recounts how he had originally been a “card-carrying antigrowth, antipopulation zealot,” but after scrutinizing the available data and following the economic science, he had evolved into one of the fiercest critics of the environmental movement. Rejecting what he called the conventional litany on environmental degradation, Simon thus became convinced that the environment “is increasingly healthy, with every prospect that this trend will continue,” and that “the material conditions of life will continue to get better for most people, in most countries, most of the time, indefinitely.”Footnote 19 Echoing Simon’s message, the interview ended by stating, “The world is not coming to an end. Things are not running out. Time is not short. So, smile! Shout! Enjoy the afternoon!”Footnote 20
Perhaps inspired by Simon, a conversion story is also central to Lomborg’s self-understanding and the promethean position he carved out for himself. Before stumbling upon the interview with Simon in 1997, Lomborg was—he has claimed from The Skeptical Environmentalist onwards—“an old left-wing Greenpeace member and had for a long time been concerned about environmental questions.”Footnote 21 As such, he initially dismissed Simon’s claims as “right-wing propaganda.” But Simon’s contrarian arguments stuck with him, and, immediately after returning to Denmark, Lomborg decided to form a study group with some of his best students to scrutinize and disprove Simon’s results. However, while not all of Simon’s claims were correct, the tests run by the study group seemed to support his overall conclusions—much to Lomborg’s surprise. It was, he has repeatedly emphasized, this awakening experience that turned him from a Greenpeace member into a skeptical environmentalist.
In The Skeptical Environmentalist, Lomborg followed Simon and used his method of investigating environmental and developmental trends over time to measure what Lomborg called “the real state of the world,” as opposed to the fearmongering of the environmental movement. His claims, as Dryzek mentions, largely echoed those made by Simon decades ago: “natural resources, energy, and food are becoming more abundant, fewer people are starving, life expectancy is increasing, pollution is eventually reduced by economic growth, species extinction presents a limited and manageable problem, forests are not shrinking.”Footnote 22
The Skeptical Environmentalist became one of the most debated environmental books in the 2000s, receiving huge praise from various nonscientific media and conservative forces as well as devastating critique from environmental activists and scientists. The book was considered by many a clear case of bad science which did not reflect the relevant literature well. For example, Harvard biologist E. O. Wilson accused Lomborg of “willfull ignorance.”Footnote 23 Moreover, critics pointed out that Lomborg lacked the foundational expertise typically required to engage credibly in complex scientific debates. He had no formal background in environmental science—no education or training in the field, no Ph.D. on environmental topics, and no relevant publications in peer-reviewed scientific journals.Footnote 24
In Denmark, however, Lomborg had already made the headlines in 1998, when he was allowed to write four editorials on the environment in the left-leaning newspaper Politiken. Here he presented the main arguments of the book Verdens sande tilstand (The True State of the World) that appeared the same year and was published in a translated and enlarged version as The Skeptical Environmentalist in 2001. These editorials and Verdens sande tilstand caused an uproar in Danish political debate. Environmentalists and scientists of various backgrounds wrote letters and articles opposing Lomborg’s arguments, and Lomborg locked horns with the Social Democratic minister of environment and energy, Svend Auken, who in the 1990s became famous nationally and internationally for promoting ambitious climate and environmental politicies.Footnote 25
It was also as a message to Svend Auken that the newly elected prime minister from the economically liberal party Venstre, Anders Fogh Rasmussen, appointed Lomborg as director of his newly established Environmental Assessment Institute in 2001. Fogh Rasmussen’s support of Lomborg aligned with his broader cultural war against government experts and “judges of taste” (smagsdommere), which defined his entry into office. This campaign led to significant cuts in the public sector, including the Ministry of the Environment.
However, prior to assuming power in 2001, Fogh Rasmussen had espoused a much more radical libertarian critique of the environmental movement and the regulatory state. Throughout the 1990s, he condemned the environmental movement and its push for state-driven regulations as a form of “ecototalitarianism,” claiming that the environmental and climate concerns justifying this expansive state intervention were exaggerated and highly debatable. While his libertarian climate skepticism softened over time, Fogh Rasmussen’s market-oriented approach to environmental policy gained in strength as he rose to power. During his tenure as prime minister, he championed a slogan of “The most environment for the money.” In this context, Lomborg’s cost–benefit framework made him the ideal figurehead for Fogh Rasmussen’s efforts to halt and reverse the policies implemented by Svend Auken.Footnote 26
At this time, while being propelled into international stardom in the early 2000s, environmental scientists filed a complaint to the Danish authorities accusing Lomborg of scientific fraud and misconduct in Verdens sande tilstand.Footnote 27 During the controversy, he left the Danish Environmental Assessment Institute in 2004. In February 2005, Lomborg stepped down from his position at Aarhus University, and by May he had taken up a role as adjunct professor in the Department of Management, Politics, and Philosophy at Copenhagen Business School—presumably through the support of economist Nikolaj J. Foss, who has been associated with Danish libertarian circles since the 1980s.Footnote 28 At the Copenhagen Business School, Lomborg set up the Copenhagen Consensus, a project that brought economists together to prioritize solutions to the planet’s biggest problems. In 2006, this project was institutionalized as the Copenhagen Consensus Center (CCC), funded by the Danish government and headed by Lomborg. At the same time, Lomborg increasingly turned his focus to the international arena. In 2008, the CCC was registered in the US as a nonprofit organization. Since 2012, when the newly elected Danish Social Democratic government cut its funding, the CCC has relied primarily on private donations.Footnote 29 Through the CCC, Lomborg has edited several volumes that showcase his signature cost–benefit approach to global issues.Footnote 30 Alongside this work, he has published three more polemical monographs in the vein of The Skeptical Environmentalist: Cool It: The Skeptical Environmentalist’s Guide to Global Warming, False Alarm: How Climate Change Panic Costs Us Trillions, Hurts the Poor, and Fails to Fix the Planet, and Best Things First.Footnote 31
Lomborg thus achieved international fame by propagating more or less the same message as Simon had decades earlier. Crucially, however, Lomborg did in fact see climate change and environmental problems as real issues that needed to be addressed. But this had to be done in a calm and measured way, by assessing the actual costs and benefits of concrete policies. As such, in stark contrast to Simon, who crafted a contrarian and highly polemical persona for himself, Lomborg’s fame has largely been underpinned by doing the exact opposite. Besides styling himself—especially in the US—as a progressive, homosexual, vegetarian, former Greenpeace member, Lomborg has presented himself as a heroic realist, who seeks to expose green dogma to new scientific scrutiny without taking sides in the heated debate. “I’m being misused by both sides,” he stated in a 2010 interview, adding that he “fundamentally” agreed with Al Gore, but that his views had been falsely portrayed by both skeptics and those who favor drastic cuts in carbon dioxide emissions.Footnote 32 In this way, Lomborg has crafted an image as a “pragmatic” public intellectual who occupies a “middle ground” in the debate, positioning himself as someone capable of bridging academia, media, business, and politics to identify the best solutions to global societal challenges.Footnote 33
Lomborg’s ideas, however, appear to circulate especially within an overwhelmingly conservative and male intellectual universe that is shaped by a technocratic ethos and a preference for presumably “commonsense” solutions. In a recent Financial Times interview, conducted on the occasion of Lomborg’s appearance at the Alliance for Responsible Citizenship conference in London, Lomborg was asked what a self-described “left-leaning Scandinavian” was doing with all these conservatives. Wasn’t he just being “a useful idiot”? Lomborg responded that while the event had a little “too much God” for his taste, he wanted “both the right and left wing to be better informed” and insisted that he was not a useful idiot but a “useful smart guy.”Footnote 34 As mentioned, Lomborg has also visited programs hosted by figures of the so-called “intellectual dark web,” like Ben Shapiro, Jordan Peterson, and Joe Rogan.Footnote 35 But Lomborg doesn’t neatly align with figures like those in the “intellectual dark web” or the “manosphere.”Footnote 36 For example, in a typically wide-ranging discussion on The Joe Rogan Experience, Rogan and Lomborg brought very different worldviews to the conversation: Rogan fixated on the harmful effects of microplastics on reproduction and masculinity, while Lomborg stressed the usefulness of plastic. True to form, Lomborg countered with a civilizational perspective, arguing that everything poses both problems and benefits—and the key is to maximize the benefits.Footnote 37 Not easily categorized, his pragmatic focus on solutionism, action, and common sense resonates with online spaces that value technological optimism, antiestablishment thinking, and male-driven authority.
Lomborg’s pragmatic intellectual persona thus allows him to connect to many political, cultural, and ideational spheres with largely the same message. However, it is clear that, rather than contributing original ideas, he has primarily picked up, repackaged, and circulated the thought of others. But beyond Simon, who are the key intellectual influences shaping Lomborg’s planning prometheanism? What are its fundamental ideological features? And in what ways and to what extent does he reproduce or reinterpret the ideas of his sources of inspiration?
Climate economics: from Julian Simon to William Nordhaus
There is no doubt that Julian Simon provided the initial impetus for Lomborg’s shift toward “skeptical environmentalism,” with Simon’s focus on assessing human welfare through trends and statistics remaining central to Lomborg’s work. However, the work of climate economist William Nordhaus has, since the early 2000s, overshadowed Simon as Lomborg’s main source of inspiration. Following Nordhaus, Lomborg’s approach to climate change reflects the growing authority of economism, where economic frameworks and cost–benefit analyses are treated as ultimate arbiters of environmental policy, sidelining other crucial perspectives.Footnote 38 While Cool It and False Alarm frequently reference Nordhaus, neither contains any mention of Simon, and both go far beyond Simon’s contributions, analytically and politically. Hence a closer examination of Nordhaus’s work and its role in Lomborg’s planning prometheanism is warranted. This entails considering Nordhaus’s scientific ethos, which Lomborg draws upon.
Nordhaus was trained in neoclassical growth economics at MIT, receiving his Ph.D. degree there in 1967, and made his name as a young economist attacking the 1972 Limits to Growth report, which questioned the strong belief in growth that MIT economists championed. In a series of polemics, Nordhaus challenged its methodology and argued that markets can help solve optimization problems until a “backstop technology” can be found that allows for infinite supply.Footnote 39 In the mid-1970s, Nordhaus had begun to focus on the tradeoffs between growth and global warming, a theme that has remained key to his work on the greenhouse effect since the early 1990s, where, in the wake of the Brundtland report and the Rio summit, he started to analyze the policies that would be introduced in order to slow climate change.
In the 1990s, Nordhaus emerged one of the foremost figures in the field of climate economics, with his pioneering work on the economic modeling of climate change earning him a central place in both academic and policy discussions. His most influential contribution, the DICE model (dynamic integrated climate economy), integrates economic and climate systems to assess the costs and benefits of addressing climate change. Nordhaus’s approach is grounded in mainstream economic thought, emphasizing cost–benefit analysis as a critical tool for formulating climate policy. His work has provided a framework for evaluating the economic implications of climate action and has influenced a range of international policy discussions, from carbon pricing to global climate negotiations. Receiving the Nobel Memorial Prize in Economic Sciences in 2018 further cemented his standing as a key figure at the intersection of economics and environmental policy.Footnote 40
Nordhaus argues that the impacts of climate change will likely be far less severe than climate scientists have predicted, and that it is not cost-effective to take strong political action now. Instead, he advocates for a gradual approach, focusing on emissions reductions via a steadily increasing carbon tax. His key policy recommendation over the past forty years has been to delay aggressive climate action, arguing that it will be more economical to address the issues as they arise—primarily through adaptation measures. He maintains that economic growth will continue despite climate change, meaning that future investments and technological advancements will better equip us to manage the consequences when they become more apparent.
However, Nordhaus’s models and conclusions have come under increasing criticism in recent years. Many commentators argue that his opposition to more aggressive emissions reduction policies promotes a dangerously incremental approach to climate action—one that prioritizes economic efficiency at the expense of the urgent need for substantial emissions cuts.Footnote 41
Critics have further asserted that Nordhaus’s arguments for political inaction rest on several idealized assumptions. First, his DICE models have historically not adequately accounted for tipping points, and this has been a major source of critique. In recent years, Nordhaus and others have acknowledged these limitations, and there have been attempts to incorporate tipping points into modified versions of his IAMs (integrated assessment models). Second, critics contend that his use of high discount rates systematically undervalues future climate damage, downplaying the urgency and scale of necessary climate action. By prioritizing economic efficiency and present-day costs, his approach reinforces a technocratic framework that, while internally consistent, has been widely criticized as both ethically flawed and ecologically insufficient given the escalating climate risks.Footnote 42
Nordhaus does not entirely ignore that his analyses are characterized by uncertainties. For example, he has used the term “best guess” about his models and stressed that they are “highly speculative.”Footnote 43 Lomborg, however, has ignored these critiques in his extensive, and selective, use of Nordhaus.Footnote 44 Drawing heavily on Nordhaus’s framework, particularly the emphasis on economic efficiency and technological solutions, he has extended these arguments into a broader polemic against mainstream climate action. In doing so, he transforms Nordhaus’s more measured economic analysis into an ideologically charged vision of planning prometheanism, using economic authority to justify delayed mitigation and the prioritization of economic growth over environmental regulation.
Lomborg’s reliance on Nordhaus, which shapes both his analysis of the costs of reducing CO2 emissions to mitigate global warming and his broader approach to societal challenges, can be traced back to The Skeptical Environmentalist. Here, Nordhaus’s work is mobilized in an analysis of the cost of cutting CO2 in the book’s final thematic chapter on global warming.Footnote 45 Along with fifteen references to Nordhaus’s writings, the section names him as the authority on which its analysis of global warming relies. Following Nordhaus, Lomborg derided most of the scenarios of the Intergovernmental Panel on Climate Change and argued that, given the amount of greenhouse gas reduction required to combat global warming, the 1998 Kyoto Protocol was grossly insufficient. Full compliance with the Kyoto Protocol, he contended, would gain us only a six-year delay in warming. In line with this, Lomborg argued for adaptation to warming rather than prevention, noting that “it will be far more expensive to cut CO2 emissions radically than to pay the costs of adaptation to the increased temperatures” and (citing Nordhaus directly) that “the optimal policy calls for a relatively modest level control of CO2.”Footnote 46
In the concluding chapter, Lomborg extended Nordhaus’s cost–benefit approach to global warming, applying it to broader global challenges. In this context, he argued that environmental threats to human prosperity are overstated and that the importance of global warming in terms of policy priority is low compared to other policy issues such as fighting poverty, disease and aiding poor countries, which all have a more direct and immediate impact in terms of both welfare and the environment. “The current outlook on the development of global warming,” he noted, “does not indicate a catastrophe.”Footnote 47 Global warming is not, Lomborg emphasized, “anywhere near the most important problem facing the world.”Footnote 48 In elaboration, his conclusion called for setting priorities and assessing risks through global cost–benefit analysis before deciding on future measures to address the global challenges facing humanity. This exemplifies how Lomborg used Nordhaus to identify a common concern—that the Kyoto Protocol was insufficient to address climate change—while recommending a policy that did not prioritize climate action, thus diverging from mainstream environmentalism.
Overall, the final two chapters of The Skeptical Environmentalist outlined the key elements of the new prometheanism that Lomborg developed in the 2000s. This prometheanism centers on global warming, arguing that reducing greenhouse gases is economically unjustifiable and that climate change is not one of the world’s most urgent challenges. Lomborg applies a cost–benefit approach to societal issues to support these conclusions. This methodology also underpinned Lomborg’s Copenhagen Consensus, which involved a comprehensive analysis of the costs and benefits of development priorities conducted by neoclassical economists. Culminating in a meeting in 2004—and the ensuing publication Global Crises, Global Solutions—the discussion positioned controlling AIDS, fighting malnutrition, and reducing trade barriers as its top priorities, while preventing climate change was at the very bottom.Footnote 49 Later publications from the Copenhagen Consensus Center, and Lomborg’s three other monographs, Cool it, False Alarm, and Best Things First, offered similar conclusions. Nordhaus, and not Simon, emerges as the primary influence shaping Lomborg’s analysis of global warming and broader global challenges.
One of the many ways in which Lomborg’s prometheanism goes beyond Simon’s is by not only assessing human welfare but also emphasizing the need for “public policies” to address global challenges such as poverty and global warming. Lomborg’s political ambition to intervene in the economy introduces a crucial new layer to the promethean economization of environmental discourse found in Simon’s work. This addition, as explained below, stems from a divergent understanding of markets and politics, and of their relationship, which is influenced by Nordhaus’s work.
Focusing on the relation between price signals, resource scarcity, and growth, Simon argued that as resource scarcity increases, prices will rise and force us to value resources and create incentives for the invention of alternatives.Footnote 50 Such faith in the ability of market dynamics to solve environmental challenges and crisis through innovation is also key to Lomborg’s work from The Skeptical Environmentalist onwards. “[I]f price increases,” he wrote in the book, “this will increase the incentives to find more deposits and develop better techniques for extracting resources.”Footnote 51 The logic here is that measures toward substitution and technological development will be taken in due course, and this endeavor will also succeed, automatically. The political message of this optimistic faith in markets, technology, and human ingenuity is clear: leave people to their own devices and they will solve all problems. As a result, political intervention in the economy is seen as unnecessary and counterproductive.
But Lomborg’s reliance on Nordhaus’s climate economics brings something different to the table. Like Simon, Nordhaus shares the basic idea that, driven by price signals, people will value scarce resources and develop substitutes, thus solving potential resource and pollution issues. However, Nordhaus diverges from Simon by advocating for government intervention to address market externalities, such as global warming, where transactions negatively impact third parties. In calling for a more active role for the state, Nordhaus combines the microeconomic assumptions about individual and firm behavior found in Simon’s work with macroeconomic theories about the economy as a whole. Unlike Simon, who believed that the market would naturally create the good society, Nordhaus’s approach resembles global household economics, where governments must influence social order by prioritizing objectives like growth and climate action, through cost–benefit analysis. Additionally, while Simon’s microeconomic assumptions are supported by empirical data on the present state of the world, Nordhaus’s macroeconomic analysis relies on mathematical models projecting future developments.
Lomborg has adopted Nordhaus’s cost–benefit approach to climate politics but takes it a step further by framing climate change as just one of several societal challenges that must be prioritized when allocating resources to improve the world. He thus adopts the ethos of a neoclassical economist, aiming to address environmental problems through politically responsible and fiscally cautious measures. While acknowledging the need to respond to environmental challenges, like Nordhaus, Lomborg subjects these issues to the analytical framework of mainstream economics. Moreover, Lomborg blends this economic discourse with the language of practical business, where the primary objective is financial gain. Every priority is evaluated in terms of whether it represents a “good” or “bad” deal for humanity.Footnote 52 By framing the “risk of human death” as the ultimate measure, Lomborg reduces the environment to an economic commodity that can be overlooked in favor of other welfare benefits, should they be deemed more valuable to humanity.
Altogether, by adopting Nordhaus’s cost–benefit approach to climate economics, Lomborg has revitalized the promethean economization of environmental discourse, aligning it more closely with mainstream economic science and political decision making. Climate economics thus allowed Lomborg to shift the debate from market efficiency to policy priorities, while also creating space for greater state involvement and planning. As we will explore below, economic analysis also provided Lomborg with concrete policy solutions to address global warming, including R & D and geoengineering.
The turn to R & D and geoengineering: the impetus from Thomas Schelling
Another key feature of Lomborg’s departure from Julian Simon’s market-based prometheanism is his embrace of technical solutions—such as geoengineering and state-supported R & D—developed through collaborations between government and business. At the heart of this more interventionist planning prometheanism lies the influence of another economist whose work on global warming has significantly shaped Lomborg’s thinking: Thomas Schelling. A professor of economics at Harvard University since 1958, Schelling is best known as a nuclear strategist who applied game theory to analyzing the dynamics of conflict and cooperation.Footnote 53 However, Schelling was a versatile scholar who wrote on a wide range of topics throughout his long career, which continued until his death in 2016, and he frequently served as a consultant to governments and think tanks of various kinds. Although this is rarely emphasized in accounts of his work, global warming was likely the subject he addressed most extensively in the latter part of his career.Footnote 54
Schelling entered the global-warming debate in 1980 when he chaired a commission for President Jimmy Carter, on which William Nordhaus also served. Stressing “the uncertainties, controversies, and complex linkages surrounding the carbon dioxide issue,” Schelling recommended “that the near-term emphasis should be on research, with as low a political profile as possible.”Footnote 55 Soon after, Schelling—again alongside Nordhaus—contributed to the 1983 National Academy report Changing Climate, which featured two distinct sections authored by economists and natural scientists, each presenting markedly different perspectives on the nature and urgency of global warming. While the natural scientists stated that global warming would occur and have serious physical and biological ramifications, the economists contended that accumulating CO2 was not a problem, or that we should simply wait and see. In his contribution, Schelling argued that it was wrong to single out CO2 for special consideration and suggested that it might be best to treat the symptoms of global warming through either deliberate weather modification or adaptation.Footnote 56 In the 1990s, Schelling began advocating for geoengineering as a serious area of research and a potential alternative response to global warming—a stance he continued to promote in his writings and talks throughout the 2000s, where it also became an increasingly prominent theme in Lomborg’s work.Footnote 57
The connection between Schelling and Lomborg dates back to the latter’s dissertation, which adopted a game-theoretical approach to international relations and conflict—an intellectual framework closely associated with Schelling’s work.Footnote 58 Schelling, a pioneer in the study of game theory and strategic conflict, was acknowledged in the only academic article Lomborg published from his dissertation.Footnote 59 Schelling was also among the economists recruited by Lomborg for the Copenhagen Consensus in 2002 and became one of the most prominent contributors to the many reports published by the center.Footnote 60 Moreover, Lomborg’s work draws on and echoes key elements of Schelling’s thinking. In addition to adopting the economistic approach to global warming that Schelling helped develop alongside Nordhaus in the 1980s and 1990s, Lomborg has shown particular affinity for the so-called “Schelling conjecture.” This is an assumption which, as Lomborg explained in False Alarm, “suggests that getting richer is likely to be the better way to help people (in poor societies), even those faced with climate problems.” In other words, it recommends a strong focus on growth and adaptation rather than on forms of mitigation.Footnote 61 In contrast to Nordhaus’s temporal focus on continued growth and future generations’ capacity to cope with climate change, the Schelling conjecture is spatially oriented, emphasizing the need for increased development in the global South. This approach is closely tied to Schelling’s long-standing engagement with international politics.
The approach has been highly influential in shaping Lomborg’s framing of global challenges, including climate change. Like Schelling, Lomborg argues that the economic development of the world’s poorest societies is the most efficient way to maximize welfare per dollar spent and address environmental challenges. According to Lomborg, as societies become wealthier, they also improve their ability to cope with environmental problems. Lomborg arguably also found inspiration in Schelling’s writings for the ideas of R & D and geoengineering that he developed during the 2000s. Already in The Skeptical Environmentalist, Lomborg wrote about “the need to invest much more in research and development of solar power, fusion and other likely power sources of the future” and of geoengineering as a “techno-fix,” which might mitigate global warming in a cost-effective way.Footnote 62 He referred to texts by Schelling and the 1992 National Academy of Sciences report Policy Implications of Greenhouse Warming, to which Nordhaus contributed, which highlighted “the relatively low costs at which some geoengineering options might be implemented.”Footnote 63
Lomborg’s advocacy for R & D as the most effective means of mitigating climate change became increasingly prominent in his writings, starting with Cool It. Here, Lomborg outlined “a more appropriate response to climate change” in the form of “a worldwide commitment to R & D for non-carbon-emitting energy technologies, aiming to lower the costs of future CO2 cuts.”Footnote 64 Explaining how technology could pave the way to a green transition, he stressed the need to financially support “research of all sorts,” “pilot programs to test and demonstrate promising new technologies,” “public–private partnerships to incentivize private-sector participation in high-risk ventures,” “training programs to expand the number of scientists and engineers working on a wide variety of energy R & D projects; government-procurement programs that can provide a predictable market for promising new technologies”; “and policy incentives to encourage adoption of existing and new energy-efficient technologies.”Footnote 65
Against this backdrop, Lomborg argued that “one of our generational challenges should be for all nations to commit 0.05 percent of GDP to R & D in non-carbon-emitting energy technologies,” claiming that this approach could stabilize the climate at a reasonable level at a much lower cost than Kyoto-style policies.Footnote 66 Following Schelling, who thought that “investment in the required R & D … will be beyond the purview of any private interest,”Footnote 67 Lomborg was not proposing a market solution, but one in which governments fund and guide R & D in collaboration with private companies. For instance, in a 2019 interview with the George W. Bush Institute, Lomborg emphasized that public R & D was preferable, arguing that private R & D “is inevitably focused on the next five years,” and that government planning is essential to facilitate and economically incentivize the long-term innovation needed to address global warming.Footnote 68
In Cool It, Lomborg also suggested a concrete technology that could be developed through collaboration between government and business as an “alternative solution” to address climate change—geoengineering. More specifically, referring to the British physicist John Latham, he proposed to “increase the reflectivity of low-lying clouds by creating more salt droplets from the ocean,” an approach known as solar radiation management (SRM), a form of geoengineering aimed at reflecting sunlight back into space to limit or reverse climate change.Footnote 69
These ideas were further developed in the 2010 film version of the book, where Lomborg enthusiastically argued that the most promising avenue of geoengineering was to invest billions in accelerated research on SRM. Again drawing inspiration from Latham, Lomborg specifically championed the idea of having 1,900 robotic ships patrolling the Pacific Ocean, churning seawater into the upper atmosphere to block sunlight.Footnote 70 The specific technique is known as cloud brightening.
The immediate inspiration for Lomborg’s geoengineering proposals in the 2010 movie came from a report written by the economists Lee Lane and Eric Bickel under the auspices of the American Enterprise Institute for Public Policy Research. In the report, which was published by Lomborg’s Copenhagen Consensus in 2009, Bickel and Lane made a strong case for the net benefits of SRM and argued for further investment and research into the technology.Footnote 71 Not only were Bickel and Lane steeped in climate economics, referring to the work of Nordhaus twenty times, but they also cited Schelling and Nordhaus for having “suggested further exploration” into climate engineering.Footnote 72 Like Schelling, while critical of excessive action on climate change, Nordhaus has argued since the early 1990s that research into climate engineering could be the most effective investment to combat global warming.Footnote 73
To be clear, neither Schelling nor Nordhaus became outright enthusiasts for geoengineering. Both cautioned that it could have devastating side effects when attempting to manipulate the Earth’s climate. For instance, Nordhaus has referred to geoengineering as a “salvage therapy.”Footnote 74
However, they were early proponents of introducing the idea into mainstream economics. The concept was assessed primarily in economistic terms, with Nordhaus arguing that geoengineering technologies would be “far more cost-effective than plugging oil wells and shutting down coal mines.”Footnote 75 Schelling’s interest in geoengineering was particularly tied to his belief in its potential to ease international conflicts and tensions by reducing “the complicatedness of what nations have to do internally to cope with greenhouse problems and what nations have to do internationally to cope with greenhouse problems.”Footnote 76 From these overlapping perspectives, Schelling and Nordhaus played key roles in introducing geoengineering into economic discourse and placing these technologies on the political agenda as a potentially valuable response to climate change that warrants further research.
The 2000s saw an increased interest in geoengineering, driven in part by renowned Dutch metereologist and atmospheric chemist Paul Crutzen, who in 2006 called for research into the possibility of reflecting sunlight away from Earth by injecting sulfur particles into the stratosphere.Footnote 77 In 2009, the British Royal Society published a widely read report called Geoengineering the Climate.Footnote 78 The report outlined two ideas that have since been widely discussed: solar radiation management and carbon dioxide removal. It was within this fertile climate for debating geoengineering research that Lomborg’s CCC published the Bickel and Lane report. This publication coincided with the center’s efforts to establish geoengineering as a significant subtheme at the COP15 meeting in Copenhagen in 2009.Footnote 79
In highlighting the “techno-fix” of geoengineering as a possible solution to global warming, like Schelling and Nordhaus, Lomborg has stressed that climate-altering plans could have dangerous unforeseen consequences and that he is not advocating the implementation of geoengineering today or in the near future. Rather, he frames it as an “insurance policy”—a precautionary measure for addressing climate risks.Footnote 80 However, while defending geoengineering against its critics, Lomborg argues that “the research done so far is actually encouraging” and suggests that it could prove to be “the earth’s best back-up plan.”Footnote 81 For Lomborg, geoengineering represents a potentially “strong” and “cheap” solution in comparison to politically driven mitigation measures. He believes it can buy time for the development of other technological solutions to global warming and support continued economic growth, which in turn can help societies adapt to a changing climate.
Technocratic politics and rebooting the 1950s
Since the 2000s, Bjørn Lomborg’s list of policies for addressing climate change has noticeably expanded and been more systematically organized. In False Alarm, he presents a “How to Fix Climate Change” section, outlining five different solutions to the problem. Following Nordhaus, Lomborg recommends a modest, gradually increasing carbon tax; innovation through R & D investment in energy storage, nuclear energy, carbon capture, and other “breakthrough technologies”; adaptation by investing in planning and infrastructure to protect against climate change; geoengineering, which he believes “might prove to be the earth’s best backup plan”; and prosperity, which, citing Schelling, he argues is a “highly effective climate policy.”Footnote 82
But what, more exactly, are the ideological commitments that underpin the policy approach in Bjørn Lomborg’s planning prometheanism? As William B. Meyer argues in The Progressive Environmental Prometheans, prometheanism does not necessarily align with the right wing and should not be conflated with outright climate denialism or a straightforward commitment to free-market capitalism.Footnote 83 Nevetheless, in his revolt against the Malthusian strand of the environmental movement, Simon criticized its proposals to restrict individual freedom—such as through birth control and limits on migration—as a response to the looming “limits to growth.” Instead, he wanted governments to step back and allow individuals and markets to solve societal challenges. Lomborg, on the other hand, has emphasized since The Skeptical Environmentalist that the goal of his interventions in the environmental debate is to improve the functioning of democracy by providing people with the best possible information.Footnote 84
However, Lomborg has, in fact, pursued a more technocratic than democratic mode of government. Like other “techno-fixers” before him, he believes that specialized knowledge and technological innovation are better equipped to address social problems than traditional educational or political methods.Footnote 85 Indeed, his advocacy for a scientific approach to societal problems is closely tied to a strong skepticism toward the effectiveness of public deliberation and majority voting as mechanisms for political decision making. His preference for technocratic decision making reflects a skepticism of democracy, rooted in the rational-choice theory pioneered by scholars like Schelling from the 1950s onward, particularly in projects within research and development agencies such as RAND.Footnote 86 Rational-choice theory, in the broadest sense, is a framework for analyzing individual and social economic behavior that became central to postwar neoclassical economics. It assumes that individuals act in alignment with their personal interests. The shift toward rational-choice theory sparked growing disagreement in economics over how to identify and aggregate individual values that could guide collective decision making. Many scholars, in fact, argued that no democratic process can reliably aggregate individual preferences into a clear, unambiguous result.Footnote 87
By applying the assumptions of rational choice to the study of politics, public-choice scholars have been influential both within and beyond economics in framing the political arena as a marketplace, where individuals are motivated by self-interest rather than a concern for the common good. According to this perspective, politicians are more concerned with winning the next election than with the feasibility or desirability of their policies; the media prioritize selling newspapers over reporting facts; scientists are driven more by fame than by a commitment to objectivity; businesses focus solely on profit; and voters are primarily concerned with their immediate needs, often failing to see through a deeply flawed political system.Footnote 88
These perspectives run like a thread through Lomborg’s writings. In a section in Cool It, titled “Politics: The Loss of a Sensible Dialogue,” he noted about the allegedly self-interested politician, “Global warming has for a long time been the perfect issue because it allows the politician to talk about things that have grandeur and yet are close to people’s heart. It actually makes some taxes popular, and yet the true costs of the policies are far removed.” While “reaping goodwill” and boosting their current popularity, those politicians enforcing climate politics “will generally not be the same ones to bear the costs of abiding by the restrictions.” And “when the time comes to commit to the political rhetoric of global warming, support suddenly withers away, because governments know that CO2 cuts will quickly become very expensive and likely to be politically dangerous.”Footnote 89 Broadening his critique to include the media and NGOs, Lomborg saw little hope for a sensible approach to global-warming politics: “This then is the depressingly obvious but debilitating consequence of the many years of politicians, the media and NGOs riding global warming, accepting and even reveling in the language of ‘fear, terror and disaster’. We have created a situation that is portrayed as ever more apocalyptic, but we have lost the opportunity of a sensible dialogue.”Footnote 90 The sensible dialogue, Lomborg stressed, is located in the terrain of economics. Or, we might add, in the domain of cost–benefit analyses. According to Lomborg, humanity’s challenges should be entrusted to a technocracy of economists (and other scientists), who can rationally address the world’s problems by focusing on economic growth and technological innovation, without being hindered by the flawed processes of traditional political democracy and decision making. This message runs through all of Lomborg’s writings.Footnote 91
These technocratic features further highlight the differences between the political commitments of Lomborg’s planning prometheanism and Simon’s market prometheanism. Both advocate policies that align with and enhance market mechanisms. In line with Simon’s emphasis on markets, securing global growth through trade liberalization has consistently topped Lomborg’s policy recommendations. However, unlike Simon, who trusts the market to handle most societal issues, Lomborg has revitalized prometheanism by advocating for a politics centered around expert rule, economic growth, and R & D—an approach that involves political planning and significant state investment. Both share a skepticism toward traditional political decision making, but while Simon places trust in the market to fulfill this role, Lomborg assigns it to experts and specialists.
Lomborg’s focus on combating climate change primarily through increased economic growth, directed technological innovation, and scientific advancement illustrates how he has shifted away from Julian Simon’s market rhetoric in favor of a planning discourse. However, from a broader historical perspective, rather than considering the planning aspects of Lomborg’s prometheanism as entirely novel, they could be viewed as a renaissance, or a reboot, of earlier forms of promethean thought that gained prominence in the 1950s. This decade was marked by many of the values, assumptions, and visions that continue to shape prometheanism today.Footnote 92 These include a productivist, growth-oriented, and developmental ethos; unwavering confidence in science and technology as tools to reshape both the social and natural worlds; a firm commitment to state planning; and a heavy reliance on the expertise of scientists and engineers. Illustrative of this, historians have demonstrated how the origins of modern geoengineering trace back to the 1950s, with military and state-funded research institutes aiming to expand human control over the environment for both military and civilian purposes.Footnote 93
Crucially, however, geoengineering during this period was not aimed at mitigating climate change, but instead was rooted in the era’s productivist, growth-focused, and developmental ethos.Footnote 94 In this context, the similarities with today’s prometheanism are evident. As Clive Hamilton has argued, even though the use of geoengineering today is centered on mitigating global warming, it aligns with a broader “modernist urge to exert control over nature through technological means.”Footnote 95 The same can be said for Lomborg’s more recent proposal to initiate R & D into nuclear power—another technology that demands substantial government investment to organize and implement—which was also seen as a technological panacea in the 1950s.Footnote 96 The large-scale R & D projects in geoengineering and nuclear power, characteristic of the era, were concrete manifestations of a technocratic, growth-oriented, and statist political approach. While some scholars have linked the technocratic ethos of the 1950s with a “progressive” political orientation, many of its proponents maintained an apolitical stance and harbored a deep mistrust not only of politics but also of mass democracy. They believed that experts and scientific methods should guide the process of defining and analyzing societal problems, setting the agenda for innovation to address them. In this way, experts and their technologies became pivotal in shaping plans for a better future.
The birth of the modern environmental movement in the 1960s was partly a reaction against exactly this technocratic predilection of a scientific rather than a political approach toward societal challenges which had dominated the era. In his critique of the political demands of the environmental movement, Simon emphasized the ability of markets to address ecological crises, aligning with and drawing strength from the antistatist arguments of the deregulation movement in the 1970s and 1980s. Lomborg, by contrast, has embraced a more technocratic mode of governance reminiscent of the 1950s, but tailored to the contemporary challenge of climate change. In doing so, he updates the aspirations of the 1950s with arguments drawn from Simon’s market-oriented perspective, combined with the tools of cost–benefit analysis and technological solutions inspired by William Nordhaus and Thomas Schelling, creating a program that aligns with current political trends.
Have we come full circle, then, returning to the 1950s to construct new futures? While today is undoubtedly different from that era, the renewed emphasis on planning and industrial politics suggests—as many commentators have noted—a shift in the tide. This may signal a move away from the globalized free-market neoliberalism of the past, toward more hybridized forms, such as “zombie,” “mutant,” or “post”-neoliberalisms.Footnote 97 It is in this context that, as we have argued, Julian Simon’s market prometheanism is no longer the dominant paradigm, but has been joined by planning prometheans like Bjørn Lomborg, who has adapted promethean discourse to align with the changing times. This adaptation of discourse has been closely tied to the cultivation of a new promethean persona, one that blends technocratic expertise with a pragmatic, cost–benefit approach to climate change. Lomborg’s ideas have always been embraced by right-wing institutions and organizations and, as we have argued, they are also now finding resonance in a more recent—predominantly online—right-wing ecosystem populated by figures such as Joe Rogan, Jordan Peterson, and Ben Shapiro. The affinity here has especially been the focus on pragmatic “commonsensical” solutions—an emphasis that finds an overt political agenda in the so-called “commonsense revolution” proclaimed by Donald Trump in his second presidency.Footnote 98 This revolution entails, amongst many other policies of deregulation, the removal of national environmental restrictions as well as American withdrawal from the Paris Climate Agreement. Lomborg has not been late in positioning himself within the context of Trump’s climate policies. During Trump’s first presidency, Lomborg voiced support for the decision to withdraw the United States from the Paris Climate Agreement, arguing that the pact was largely ineffective in combating climate change.Footnote 99 Following Trump’s election victory in 2024, Lomborg reiterated this stance in the New York Post, criticizing the excessive financial demands the UN agreements placed on wealthy nations.Footnote 100
Most recently, in a rare Danish media appearance, Lomborg spoke with Ingeniøren (The Engineer) about the energy and climate policy implications of the Ukraine War and Trump’s push for increased military spending in Europe. Unlike the US, which has achieved energy independence through fracking, Lomborg criticized the EU for spending vast sums on what he sees as inefficient energy sources like wind and solar. Rather than pursuing what he calls the futile goal of climate neutrality by 2050, he argued that the EU should invest those funds in rebuilding military capabilities and boosting R & D in technologies like small modular reactors and fusion power. “The point is,” Lomborg said, “if we get just one of these technologies to become cheaper than fossil fuels, then we don’t have to convince the rest of the world—they’ll switch because it’s cheaper.”Footnote 101
These instances indicate that Lomborg is willing to align, and presumably also adapt, his planning prometheanism in accordance with the changing tides of twenty-first-century climate policy. However, this adaptation does not seem to involve too much strain. The simplicity of Lomborg’s technological optimism and cost–benefit approach—although harvested from well-respected economic scientists—has provided his message with an impressive consistency that’s only fine-tuned in the margins according to context and developments. As he himself concludes in his recent interview with Ingeniøren, “My argument has always been that good arguments tend to win. Not immediately, but slowly the good arguments erode the bad arguments. That’s why I’m sitting here and saying these things again, and that’s why I’ve been saying them for over 20 years. And eventually I will probably end up being right.”Footnote 102 Whether that is the case remains to be seen, but planning prometheanism certainly looks like it is here to stay.
Acknowledgments
We would like to thank Julia Norblad, Jenny Andersson, Troy Vettese, Kristoffer Ekberg, Mikkel Thorup, and the two anonymous referees for valuable comments on this paper.