ECC3640 Chap.2 Impacts, Damages and Economic Costs
Impacts, Damages and Economic Costs
Impacts, Damages and Economic Costs explains how a physical climate hazard becomes a welfare estimate. Analysts move from hazard to physical impact, exposure and vulnerability, adaptation, market and non-market valuation, and finally residual damage. The same hazard can create different losses across places because income, infrastructure, sector mix and adaptive capacity differ.
Damage functions compress this chain so that integrated assessment models can compare damages with abatement costs, but compression can hide thresholds, unequal regional effects and values without market prices. Strong answers identify what is counted, what is omitted, whose welfare is aggregated and whether damage is measured before or after adaptation.
A hazard is not yet an economic loss.
Heat, flood or changed rainfall must intersect with exposed people, assets or ecosystems, and the resulting effect depends on vulnerability. Adaptation can reduce part of that effect, leaving residual damage. This ordering prevents double counting: avoided damage attributed to adaptation cannot also be reported as an unavoidable climate cost.
It also reveals why identical temperature changes can have sharply different welfare consequences across regions and households.
Market impacts have observable prices or income effects, although those prices may still omit externalities. Non-market impacts such as mortality risk, biodiversity, cultural heritage and amenity require other valuation methods and careful ethical interpretation.
GDP changes are therefore not a complete measure of welfare. Distribution matters because a dollar loss can impose a larger welfare burden on a low-income household, and aggregate totals can conceal concentrated harm. Damage functions offer tractability by mapping climate variables into monetary loss, yet their apparent precision depends on functional form, baseline growth, adaptation assumptions and treatment of thresholds.
In an extended response, trace the complete pathway, label uncertainty at each link, separate gross from residual damage, and test whether omitted categories would systematically bias the estimate rather than merely observing that every model is imperfect.
What this chapter covers
- 01
Climate hazards
- 02
Physical impacts
- 03
Exposure and vulnerability
- 04
Autonomous adaptation
- 05
Policy-driven adaptation
- 06
Damage functions
- 07
Market valuation
- 08
Non-market valuation
Worked example · free
Compare residual damage
- +1North residual damage is 24 × (1 − 0.50) = 12 units.
- +1South residual damage is 16 × (1 − 0.25) = 12 units.
- +1State that both regions have the same measured residual quantity.
- +2Explain that income, population and non-market loss can make welfare burdens differ.
- +1Recommend comparing adaptation cost and spillovers before ranking options.
Key terms
- Physical Impact
- A change in health, ecosystems, infrastructure or production caused by a climate hazard before monetary valuation.
- Exposure
- The people, assets, activities or ecosystems located where a climate hazard can affect them.
- Vulnerability
- The susceptibility of exposed people or assets to harm, shaped by sensitivity and the capacity to cope or adjust.
- Damage Function
- A model relationship that converts a climate variable into an economic loss under stated assumptions and boundaries.
- Residual Damage
- The harm remaining after adaptation or protective measures reduce part of the gross impact.
- Non-Market Value
- Welfare associated with health, ecosystems, amenity or culture that lacks an observed market price and requires another valuation method.
Impacts, Damages and Economic Costs FAQ
Why do equal hazards produce different damages?
Exposure, sector mix, infrastructure, income and adaptive capacity differ across places. A similar physical hazard can therefore create very different physical impacts, monetary losses and welfare burdens.
What does a damage function leave out?
Depending on its design, it may omit thresholds, non-market values, distribution, adaptation limits or regional detail. The function is a useful model component, not a complete social account.
How does adaptation enter a damage estimate?
Adaptation can reduce gross impacts, leaving residual damage. A complete appraisal also counts the adaptation cost, timing, spillovers and any risk transferred to other groups or locations.
Can market and non-market losses be added directly?
Only after they are valued on a consistent welfare basis. Output loss, mortality risk and ecosystem change measure different outcomes, so simple addition can manufacture precision if methods and populations differ.
Exam move
Draw the damage chain from hazard to welfare and attach one example to each arrow. For every number in a practice question, label whether it is gross impact, avoided damage, adaptation cost or residual damage. Learn to reject options that treat an omitted item as zero or infer equal welfare from equal dollars.
When comparing studies, check scenario, time horizon, population, price basis and adaptation assumption before ranking results. Finish explanations with the limitation most relevant to the launch pad: aggregation for a global estimate, thresholds for a smooth curve, or cost and spillovers for an adaptation result.
Practise one short paragraph that moves from physical evidence to economic valuation without skipping exposure or vulnerability.
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