Against Denialism: John Broome

Source Information

• Author: John Broome

• Publication: The Monist, January 2019, Vol. 102, No. 1, Climate Change and Value

• Page Range: 110-129

• Published by: Oxford University Press

• Stable URL: https://www.jstor.org/stable/10.2307/26614784

ABSTRACT

• Notable Philosophical Position: Many philosophers deny that an individual's greenhouse gas emissions cause harm, termed "individual denialists." This position often stems from the perceived insignificance of single actions within a global problem.

• Thesis: Broome argues that an individual's emissions can cause harm and certainly contribute to expected harm, directly challenging the foundations of individual denialism.

1. INTRODUCTION

• Two Types of Denialism:

  • Species Denialists: Deny humanity as a whole causes harm through emissions. This view is largely inconsistent with scientific consensus.

  • Individual Denialists: Deny individual emissions cause harm; this position is surprisingly prevalent among moral philosophers, often due to the perceived lack of direct causal links.

• Aim of paper: Oppose individual denialism by providing robust philosophical and scientific arguments for the causal link between individual emissions and harm.

2. SCIENCE AND ECONOMICS

Overview of Individual Emissions

• Example: Driving a gas-guzzling SUV, using $10$ liters of fuel, results in approximately $25$ kg of carbon dioxide emissions. This seemingly small amount accumulates globally.

• Definition: Social Cost of Carbon (SCC) - A monetary measure of the worldwide harm caused by one additional tonne of CO2 emissions. It quantifies damages from climate change, including things like lost agricultural productivity, human health impacts, and property damage from sea-level rise.

  • Example figure from Obama administration: $40$ per tonne, suggesting that a single joyride incurring $25$ kg of emissions would cause approximately **$1$ **of harm (calculated as $(25 ext{ kg} / 1000 ext{ kg/tonne}) imes 40 ext{ extdollar}/tonne = 1 ext{ extdollar}$).

• Lifetime Estimates: A typical academic may emit over $1,000$ tonnes of CO2 over their lifetime, leading to potential lifetime harm estimated to exceed **$40,000$ **(calculated as $1000 ext{ tonnes} imes 40 ext{ extdollar}/tonne = 40,000 ext{ extdollar}$).

• Following Considerations:

  • Contentious nature of the $40$ figure due to the difficulty of quantifying many climate change harms, differing discount rates applied to future damages, and variations in economic models and assumptions across different administrations or research groups.

  • Aspects of nature that cannot be monetized, such as the intrinsic value of wildlife preservation, biodiversity, and ecosystem services, which are often undervalued or omitted in economic calculations.

  • Many economists may use questionable methods for monetizing damages, leading to debates about the ethical and practical implications of such valuations.

• Importance of Damage Function:

  • Economists estimate global harm with a sophisticated damage function predicting comprehensive global harm as a non-linear function of total emissions each year. This function attempts to capture the complex relationships between emissions and their environmental, social, and economic consequences.

  • The SCC represents the marginal rate of change in global harm concerning emissions, meaning it describes the additional harm from one extra unit of CO2. Its value can vary significantly across years and depends on projected future emissions and economic conditions.

• Graph Illustration:

  • Figure 1 conceptually shows a large-scale damage function as an upward-sloping straight line when viewed broadly. However, at higher magnification, it reveals significant jaggedness, indicating that the actual harm from smaller, incremental emissions is not always smooth but can involve sudden, discrete changes.

• Underlying Factors of Jaggedness:

  • Discrete Events: Emissions do not cause harm continuously and smoothly; rather, they can trigger identifiable, sudden harms such as an increase in the frequency or intensity of typhoons or the outbreak of diseases like cholera due to climate-sensitive conditions.

  • Extreme Instability of the Atmosphere: The climate system exhibits chaotic behavior, which implies that even small disturbances or additional emissions can, under certain conditions, lead to disproportionately major weather changes, shifting probabilities towards extreme events.

• Historical Reference:

  • Edward Lorenz's butterfly effect vividly illustrates how minimal changes (e.g., a butterfly flapping its wings) can drastically affect weather patterns over time due to the chaotic nature of atmospheric systems. This principle applies to greenhouse gas emissions, where small additions can have significant, unpredictable cascading effects.

  • Today's emissions greatly exceed those levels of the Eighteenth Century, making the threshold for triggering significant climatic shifts much lower and directly increasing the risk and potential for substantial harm from even individual contributions.

3. EXPECTED HARM

• Argument of Uncertainty:

  • Emissions create indeterminable outcomes; the resulting harm from a specific emission may range from a catastrophic disaster to a seemingly positive localized event (e.g., warmer winters in some areas). The challenge is linking a single emission to a single outcome deterministically.

  • The ethical consideration, therefore, should hinge on the expected prospect or utility, which accounts for the probability-weighted sum of all possible outcomes, rather than focusing solely on outcomes that cannot be known with certainty.

• Definition of Prospect and Utility:

  • Prospect: A comprehensive collection of all possible outcomes of an action, along with their respective likelihoods or probabilities. For climate change, this includes a vast array of potential future states.

  • Utility: A technical term determined through expected utility theory, representing an agent's preferences over uncertain outcomes. Higher values correlate with higher utility, not necessarily higher monetary value. It accounts for an individual's attitude towards risk.

• Expected Value vs. Utility:

  • Broome distinguishes that higher risk, even if it has the same expected monetary value, may result in lower expected utility for risk-averse agents. This challenges the simplistic assumption that emissions with higher, but more uncertain, negative consequences carry equivalent expected value to those with more predictable, certain consequences. For example, a small chance of catastrophic climate collapse might have a similar expected monetary value to a certainty of minor warming, but the former would have much lower expected utility for most people.

• Conclusion Impacting Individual Action:

  • Given the scientific understanding, driving emissions yields a positive expectation of harm, meaning that on average, individual actions increase the probability and severity of negative climate outcomes. This leads to profound ethical questioning of individual enjoyment against shared harm costs and future well-being.

4. SINNOTT-ARMSTRONG AND KINGSTON

Resistance to Individual Denialism

• Sinnott-Armstrong's Arguments:

  1. Global warming persists with or without individual emissions, but individual emissions are not irrelevant; each unit of emission contributes incrementally to the overall expected rise in global harm and shifts the probability distribution towards worse scenarios.

  2. The sheer scale and cumulative nature of greenhouse gases mean that each individual emission, no matter how small, adds to the overall atmospheric concentration and thus to the total climate impact.

  3. The analogy of pouring water into a river showcases how individual actions, when aggregated, can trigger significant consequences. While one drop may not cause a flood, millions of such drops certainly will, or one drop can be the 'last straw' if the river is already at its brim.

  4. Individual emissions may not be traceable to specific, isolated climate events (e.g., identifying which SUV trip caused a particular storm), but they nonetheless contribute to the cumulative risk and increase the likelihood of such outcomes.

  5. Claims that no harm arises from individual emissions rely on unlikely assumptions that neglect atmospheric instability, the potential for non-linear effects, and the continuous negative processes caused by increased greenhouse gas concentrations.

5. OVERDETERMINATION

• Defining Overdetermination:

  • This concept describes situations of collective responsibility where harm or an outcome is caused by multiple factors, and each individual's action, while not uniquely necessary for the harm to occur, nevertheless contributes to the cumulative harm. For instance, if $10$ people push a car that $9$ people could have pushed, each of the $10$ overdetermines the car's movement.

• Elizabeth Cripps' Claim:

  • Cripps posits that harm from climate change can be attributed to collective overdetermination, arguing that no single individual act can be isolated as the sole or unique cause of a global warming event. This perspective can lead to diffusing individual responsibility by emphasizing the collective nature of the problem.

• Counterarguments:

  • The unpredictability of individual emissions influencing climate events, coupled with the chaotic nature of the atmosphere, necessitates recognizing that personal contributions may indeed lead to major consequences, even if the specific causal chain is indeterminate. Your action could be the 'trigger.'

  • Broome emphasizes that the 'jumps' in the damage function, where small increments of emissions can trigger significant discrete harms, directly challenge the idea that individual actions are irrelevant. Every individual's actions impact the overall outcome by shifting the system closer to such thresholds.

6. IMPERCEPTIBLE HARMS

Denialism on the Basis of Insignificant Harm

• Argument Summary:

  • This assertion claims that because the harm done by an individual's emissions is so microscopically small, it is essentially negligible or non-existent, and thus carries no moral weight. It's an argument often used to justify inaction.

• Counterarguments Against Insignificance:

  • Broome acknowledges that imperceptible harms can indeed cumulate to significant, perceptible damage. He draws an analogy to physics, where countless small atomic events lead to nuclear reactions, or how individual grains of sand, imperceptible on their own, collectively form a vast beach.

• Refuting Claims of Imperceptibility:

  • The existence of 'jumps' in the damage function directly refutes the idea that all individual harms are imperceptible. These jumps reveal that even a small emission increment can sometimes be the factor that tips the global system into causing perceptible outcomes, such as one additional death from heatwave stress or a new outbreak of a climate-sensitive disease.

• Broome's Assertion:

  • Both claims of imperceptibility – that individual harms are simply too small to matter and that they can never lead to perceptible outcomes – are false. He highlights the urgent need to recognize the reality and impact of even individual climate change contributions.

7. CONCLUSION

• Reflection on Individual Denialism's Consequences:

  • Individual denialism promotes apathy toward climate change amongst the general public and unnecessarily complicates the ethical discussion for philosophers, distracting from actionable moral responsibilities.

• Urging Philosophical Clarity:

  • Broome calls for a more straightforward and robust approach to understanding the effects of individual emissions, pushing moral philosophers to focus on real ethical responsibilities rather than getting bogged down in theoretical complexities that undermine action.

• Emphasis on Expected Harm:

  • The ethics of climate change fundamentally involves acknowledging and taking responsibility for the expected harm created by individual emissions, and acting accordingly to mitigate it through personal and collective effort.

NOTES / REFERENCES

1. Various works by Elizabeth Cripps, Kingston and Sinnott-Armstrong, Maltais, and Sinnott-Armstrong outlining the denialist arguments and philosophical implications. These sources contribute to the broader academic debate Broome engages with.

2. Citing of various economic estimates and models that influence the discussion on SCC and individual responsibility towards climate emissions, highlighting the interdisciplinary nature of the climate change ethical problem.

APPENDIX: KAGAN AND IMPERCEPTIBILITY

• This section discusses Shelly Kagan's denial of the imperceptibility of harms, where he posits that even tiny, seemingly insignificant impacts (e.g., changes to water tables at a molecular level) can lead to significant implications and have real effects, even if unobservable by humans.

• It explores the challenges in measuring such small changes and their overall effectiveness, particularly using hypothetical examples of minute impacts on water tables, emphasizing that difficulty in detection does not equate to non-existence of harm. Kagan suggests that if small actions lead to small harms, and enough small harms exist, they collectively contribute to a larger problem that is indeed perceptible.