Bjorn Lomborg on the Costs and Benefits of Attacking Climate Change

Episode Summary

Executive Summary: Russ Roberts and Bjorn Lomborg debate climate change through a cost-benefit lens. Lomborg argues global warming is real but manageable, that catastrophic tail risks are unlikely to be reduced much by current emissions policy, and that adaptation, poverty reduction, and especially cheap innovation or geoengineering matter more. Roberts agrees on many trends but stresses uncertainty, unpriced losses, and the need for humility about what can be measured.

Main Topics: Climate change severity and expected damages (Priority: 5/5): Lomborg frames warming as a real but non-apocalyptic problem, citing projected GDP losses that are meaningful but manageable relative to future wealth. Tail risks and geoengineering (Priority: 5/5): The discussion turns to catastrophic scenarios, with Lomborg arguing that only geoengineering could quickly affect extreme outcomes, and Roberts questioning whether society should prepare for such wildcard solutions. Adaptation and observed climate impacts (Priority: 5/5): They review sea level rise, hurricanes, droughts, floods, and polar bears, with Lomborg emphasizing adaptation, better data interpretation, and declining death tolls despite climate-related hazards. Policy effectiveness and carbon pricing (Priority: 4/5): Lomborg argues current climate policy is too costly relative to its benefits and that emissions cuts alone would have limited near-term effect; he favors R&D over large-scale deployment subsidies. Alternative priorities: poverty, health, and nutrition (Priority: 4/5): A major thread is that resources spent on climate could do much more good elsewhere, including vaccinations, tuberculosis treatment, contraception, and childhood nutrition. Limits of quantification and moral judgment (Priority: 4/5): Roberts cautions that cost-benefit analysis can miss dignity, biodiversity, cultural loss, and other unpriced values, while Lomborg defends numbers as a practical menu for choosing among policies. Lomborg’s broader case for evidence-based policy (Priority: 3/5): The conversation revisits The Skeptical Environmentalist and the Copenhagen Consensus, highlighting Lomborg’s effort to rank interventions by social return rather than by emotional appeal.

Key Arguments: Global warming is a problem, but not an existential one; projected damages are significant yet small relative to expected future global wealth. Most realistic emissions policies will have only trivial effects on near-term climate outcomes and far-tail risks like extinction. If society truly fears catastrophic climate outcomes, geoengineering is the only policy tool likely to work quickly enough to matter. Many climate harms are more effectively addressed through adaptation, richer infrastructure, and poverty reduction than through carbon cuts alone. The largest gains may come from cheap, high-return interventions in health, nutrition, contraception, and trade rather than from expensive climate mitigation. Current climate spending is skewed toward politically visible but low-impact subsidies, especially for mature solar and wind technologies. Roberts agrees that many trends are improving but argues that non-monetary values and uncertainty make purely quantitative rankings incomplete. Both speakers see deep public-policy failure: governments often underinvest in long-term, high-return solutions while overreacting to symbolic actions.

Data Points: Projected net impact of global warming by 2070s: 0.2% to 2% of GDP - Lomborg cites UN-climate-panel-style estimates of near-to-midterm damages Projected cost by end of century: 2% to 4% of global GDP - Lomborg’s estimate for unmitigated warming by 2100 Future global wealth multiple: 5 to 10 times richer - He argues the world will be far wealthier by century’s end, making damages more manageable Sea level rise by end of century: 1 to 3 feet - Lomborg describes expected sea level rise as serious but adaptable Polar bear population: 22,000 to 28,000 - He claims population is up from the 1960s and not clearly declining Polar bear population in 1960s: 5,000 to 10,000 - Historical comparison used to argue current numbers are higher Polar bears shot annually: 300 to 800 - Lomborg says stopping hunting would help more than climate policy for polar bears U.S. flooding costs in 1903: about 2% of GDP - Historical baseline for flood damage costs U.S. flooding costs today: about 0.2% of GDP - Used to show adaptation has reduced losses Climate-related deaths in the 1920s: about 500,000 per year - International Disaster Database estimate cited by Lomborg Climate-related deaths today: about 20,000 per year - Despite population growth, deaths have fallen sharply Reduction in climate-related deaths: 95% - Derived from the comparison between the 1920s and today World population change since 1920s: quadrupled - Lomborg contrasts this with falling climate-related mortality Global climate-related costs since 1990: 0.3% to 0.25% of GDP - He says worldwide weather losses have declined over the past 30 years Cost to avoid all global warming for the 21st century via cloud brightening: about $10 billion - Lomborg’s geoengineering example involving sea-salt aerosol clouds Scale comparison for geoengineering cost: 3 to 4 orders of magnitude cheaper - Compared with the $10–$100 trillion commonly discussed for climate mitigation Spending on solar and wind subsidies: about $150 billion per year - Lomborg argues most of this goes to deployment, not R&D Paris Agreement cost: $1 to $2 trillion per year - He claims it would cost a huge amount while having little measurable effect Paris Agreement cumulative cost: about $80 trillion over the next half century - Lomborg’s estimate of long-run spending Optimal carbon tax according to Nordhaus: about $30 to $40 per ton of CO2 - Roberts and Lomborg discuss the gap between theory and current policy Current climate-policy equivalent tax: about $2 per ton of CO2 - Lomborg cites Nordhaus’s estimate of actual policy stringency Potential Doha Round poverty reduction: 170 million more people out of poverty - Lomborg’s estimate of the gains from successful global trade liberalization Income gain from Doha Round: about $1,000 richer per person per year by 2030 - Projected benefit for people in the developing world Vaccination intervention return: $60 of social benefits per $1 spent - Copenhagen Consensus estimate TB intervention return: $43 of social good per $1 spent - Copenhagen Consensus estimate Contraception program cost: $3.6 billion per year - Cost to expand universal access for 215 million women Contraception benefits: 150,000 women and 600,000 children saved - Lomborg’s estimate of mortality benefits Contraception return: $120 of social benefits per $1 spent - Including demographic and growth effects Early childhood nutrition return: $45 per $1 spent - Copenhagen Consensus estimate based on long-run productivity gains Coral reef protection return: $24 of social good per $1 spent - Used as an example of conserving valued ecosystems Guatemala nutrition study wage effect: about 60% higher wages - Long-term impact of childhood protein/nutrition versus sugar water Schooling-related productivity loss avoided by nutrition: 66% income loss avoided - Lomborg says early nutrition prevents large adult productivity losses

Pivotal Quotes: "global warming is a problem. the end of the world." — Bjorn Lomborg: Opening summary of his overall climate assessment "If you actually worry about the really far-out tail events, you should be focusing on policies that could actually help you with those." — Bjorn Lomborg: Argument that costly emissions cuts are the wrong response to catastrophic climate fears "it's not about getting it right, it's about getting it slightly less recognizable. Wrong." — Bjorn Lomborg: Closing reflection on the purpose of the Copenhagen Consensus and policy improvement

Implications: Listeners should expect climate debates to hinge on tradeoffs, not slogans: adaptation, innovation, and poverty reduction may outperform broad mitigation on welfare per dollar. But Roberts’s critique is a warning that unmeasured values and uncertainty still matter.