This review synthesises findings from 127 peer-reviewed studies, showing strong and consistent evidence that climate change increases economic inequality and disproportionately affects poorer populations across countries and regions. Results hold across physical impacts, sectors, and assessment methods.

Introduction

The report highlights that although global inequalities have declined since the late 1980s, climate change may reverse this trend. Biophysical impacts such as temperature rise, altered precipitation, extreme events and sea-level rise create unequal economic damages due to differing exposure and adaptive capacity. The objective is to determine whether, where, and through what channels climate change increases economic inequality, focusing on income and consumption measures.

Methods

A systematic search of Web of Science and Scopus (February 2023) identified 1,891 papers, reduced to 127 after screening against predefined inclusion criteria. Each study was coded by geographical scope, inequality metric, physical impact, economic sector, impact channel, and methodology. Outcomes were categorised as regressive (inequality increases or poor more affected), progressive, mixed, neutral or no conclusion. An agreement indicator summarised consistency across studies; the overall value of 0.79 indicates strong convergence towards regressive results.

Results And Synthesis

Climate change increases inequalities, both globally and within countries on all continents

Of 52 studies explicitly analysing inequality, 35 find increases, while only two find decreases in very localised contexts. Across the whole corpus, 69% conclude that climate change either increases inequality or affects poorer groups more. Among global studies, 78% identify regressive effects. Findings are consistent across continents, with China, Brazil, Ethiopia and the United States showing the strongest evidence. Only five studies identify the rich as more affected, largely due to higher-value asset exposure. Regressive outcomes occur in 75% of Global South studies and 89% of Global North studies providing conclusions.

All types of physical impacts increase economic inequalities, through several channels

Temperature-related papers (90 studies) show 72% regressive effects. Precipitation-related impacts display 60% regressive outcomes, while sea-level rise studies show 89%. Key channels include reduced labour productivity, agricultural yield losses, infrastructure damage, water scarcity and increased energy demand. Labour-related impacts disproportionately affect low-skilled and outdoor workers. Agricultural effects vary but often increase poverty where households rely heavily on farming income.

Climate change increases both household and national income inequalities

Income-based studies are most common, followed by GDP and consumption. Of 16 studies using inequality indices, 10 report increases, three mixed results, one decrease, one neutral and one inconclusive. Studies using income deciles consistently find higher burdens on poorer households.

Climate change increases economic inequality across the main assessment methods

Econometric and simulation-based studies both show more than 70% regressive outcomes (over 80% among those providing conclusions). Backward- and forward-looking assessments yield similar patterns, with projected future impacts continuing to widen economic disparities.

Discussion

The review concludes that climate change predominantly increases economic inequality. Policy implications include the need for targeted adaptation measures, prioritised support for low-income households, and international financing arrangements such as loss-and-damage funding. The authors recommend improved quantitative reporting of inequality metrics, expanded regional coverage, and greater representation of social heterogeneity to inform future modelling and policy design.