What Is Loss and Damage?

Loss and damage is the term used in international climate policy for the harms caused by climate change that mitigation and adaptation have failed to prevent. It covers the consequences of extreme events such as cyclones, floods, heatwaves, and wildfires, and of slow-onset processes such as sea level rise, desertification, glacier retreat, ocean acidification, and salinization of coastal aquifers. The concept marks a third pillar of climate response alongside cutting emissions and adapting to changing conditions, and it applies where impacts exceed the limits of what adaptation can absorb, either physically or because the cost of adapting is beyond reach.

The subject sits at the intersection of environmental economics, climate science, disaster risk management, and international law. Economists distinguish economic loss and damage, meaning impacts on assets, infrastructure, agricultural output, and livelihoods that markets can price, from non-economic loss and damage, which includes loss of life, health, cultural heritage, territory, biodiversity, and identity attached to place. The second category resists monetary valuation, which complicates the compensation frameworks built around it.

Institutional History

Small island developing states first raised the idea of an international insurance pool for climate harms in 1991, during negotiation of the Framework Convention itself. Formal recognition came much later. COP19 in 2013 established the Warsaw International Mechanism for Loss and Damage, which was tasked with improving knowledge of comprehensive risk management, strengthening coordination among stakeholders, and enhancing action and support. Article 8 of the 2015 Paris Agreement gave loss and damage standing as its own article, though an accompanying decision specified that it provides no basis for liability or compensation. The Santiago Network was added in 2019 to channel technical assistance, and COP27 in 2022 agreed to establish a dedicated fund, operationalized the following year with an initial round of pledges. An assessment in the journal Climate Policy of progress made by the Warsaw International Mechanism's Executive Committee documents how slowly the mechanism moved from knowledge generation toward the delivery of finance.

Measurement, Attribution, and Valuation

Quantifying loss and damage depends on separating climate-driven harm from harm that would have occurred anyway. Probabilistic event attribution, which compares the likelihood of an observed extreme in the present climate against a counterfactual climate without anthropogenic forcing, provides the scientific basis, and its results are increasingly cited in litigation and in claims for support. Impact valuation then combines damage functions, satellite and census-derived exposure data, and economic loss models of the kind used in catastrophe insurance. The World Resources Institute's analysis of loss and damage from climate change sets out how estimates of the annual bill for developing countries have been constructed and why they diverge so widely. Non-economic losses are handled through separate methods, including participatory valuation and displacement tracking.

Finance and Risk Transfer

Instruments for addressing loss and damage span grant-based funding, concessional finance, parametric insurance that pays out on a measured trigger such as wind speed, regional risk pools, catastrophe bonds, contingent credit lines, and debt clauses that suspend repayment after a disaster. Each has different coverage properties: insurance handles frequent, well-characterized extremes efficiently but is poorly suited to slow-onset processes with certain outcomes, which are uninsurable by construction. Debate continues over the sources of funding, the criteria for allocating it among vulnerable countries, and how the new fund relates to existing humanitarian and development channels.

Applications

Work on loss and damage draws on and informs fields including:

• Extreme event attribution and regional climate modeling
• Catastrophe risk modeling and parametric insurance design
• Remote sensing for damage assessment and exposure mapping
• Disaster early warning systems and emergency communications
• Development economics and public finance
• International environmental law and climate negotiation