Climate justice statistics show a persistent imbalance: the people and places most exposed to climate harm are not necessarily those with the greatest capacity to respond. About 3.3–3.6 billion people lived in highly vulnerable contexts in 2022, while global warming indicators continued to reach records in 2023 and 2024. The figures below separate observed measurements from forecasts and projections and keep each source’s scope explicit.
Contents
- Who is most vulnerable?
- Observed impacts
- Unequal health burdens
- Migration and displacement
- Emissions gaps and fair pathways
- Adaptation finance and capacity
Who is most vulnerable?
The IPCC estimated that approximately 3.3–3.6 billion people lived in contexts highly vulnerable to climate change in 2022 (Summary for Policymakers). A separate IPCC assessment reported that about 1.8 billion people lived in countries classified as low- or very-low-vulnerability contexts in its 2022 assessment (Chapter 8: Poverty, Livelihoods and Sustainable Development). The contrast is a reminder that vulnerability is not a single global average: it varies substantially between places and communities.
The IPCC also reported that the population in the most vulnerable regions is projected to almost double by 2100 (Chapter 8). The UNDP summarized a related estimate of around 3.6 billion people already living in areas highly susceptible to climate change in its 2023 loss-and-damage discussion (It’s time to address the devastating injustice of loss and damage).
The human and economic record is already large. Extreme weather caused at least 2 million deaths and about US$4.3 trillion in economic damage over approximately 1973–2023, according to the UNDP. More than 1 billion people are expected to be exposed to coastal-specific climate hazards by 2050. Over approximately 1873–2023, live coral reefs nearly halved. These are broad global indicators; they do not assign identical risks to every population.
Observed impacts
The State of the Global Climate 2024 reported that the 2024 global mean near-surface temperature was 1.55 ± 0.13°C above the 1850–1900 average. This is an observed annual value, not a forecast of the long-term climate state.
The same WMO report found that atmospheric carbon dioxide, methane and nitrous oxide concentrations reached their highest levels in 800,000 years in 2023. Global ocean heat content reached its highest level in the 65-year observational record in 2024, and the rate of ocean warming during 2005–2024 was more than twice the rate during 1960–2005.
Several other indicators describe the speed and reach of change:
- Global mean sea level rose at 4.7 mm per year during 2015–2024, compared with 2.1 mm per year during 1993–2002.
- The 2021–2024 glacier mass balance was the most negative three-year glacier balance on record.
- Antarctic annual minimum and maximum sea-ice extents were each the second lowest in the observed record in 2024.
These measurements matter for justice because exposure interacts with housing, infrastructure, livelihoods, health systems and public resources. A global record does not itself show who bears the cost, but it establishes the changing physical conditions in which unequal impacts occur.
Unequal health burdens
The WHO climate-change fact sheet projects approximately 250,000 additional deaths per year between 2030 and 2050 from selected causes. This is a conservative modelled subset of health pathways, not a complete estimate of all climate-related deaths. Within that selected-cause projection, about 38,000 annual deaths are associated with heat exposure among older people, 48,000 with diarrhoeal disease, 60,000 with malaria and 95,000 with childhood undernutrition.
WHO also estimates direct health damage from climate change at US$2–4 billion per year by 2030, excluding costs in sectors that determine health. The same fact sheet reports that more than 930 million people—about 12% of the world’s population—spend at least 10% of their household budget on health care, while health shocks and stresses currently push around 100 million people into poverty each year. These figures describe existing financial vulnerability alongside projected climate-related burdens.
Heat statistics show both long-term and regional disparities. The WHO heat-and-health fact sheet reports that heat-related mortality among people over 65 increased by approximately 85% between 2000–2004 and 2017–2021. Studies cited by WHO estimate approximately 489,000 heat-related deaths per year globally during 2000–2019, with 45% in Asia and 36% in Europe. In Europe alone, an estimated 61,672 heat-related excess deaths occurred during summer 2022.
| Health measure | Estimate or observation | Period |
|---|---|---|
| Additional deaths from selected causes | About 250,000 per year | 2030–2050 forecast |
| Heat-related mortality increase among people over 65 | About 85% | 2000–2004 to 2017–2021 |
| Estimated global heat-related deaths | About 489,000 per year | 2000–2019 |
| European heat-related excess deaths | 61,672 | Summer 2022 |
The table combines different measures and periods; it should not be read as a single total. In particular, the WHO selected-cause projection and the study-based global heat estimate use different methods and scopes.
Migration and displacement
The World Bank’s Climate Change Could Force 216 Million People to Migrate Within Their Own Countries by 2050 estimates that climate change could force 216 million people to migrate within their own countries across six regions by 2050 under the report’s adverse scenario. These are scenario-based projections of internal migration, not counts of international refugees.
The regional estimates are as follows:
- Sub-Saharan Africa: as many as 86 million internal climate migrants by 2050.
- East Asia and the Pacific: as many as 49 million.
- South Asia: as many as 40 million.
- North Africa: as many as 19 million.
- Latin America: as many as 17 million.
- Eastern Europe and Central Asia: as many as 5 million.
The World Bank also projects that concerted emissions cuts combined with green, inclusive development could reduce the projected scale of internal climate migration by as much as 80% by 2050. That result makes migration a policy-sensitive justice issue: future displacement is shaped not only by physical hazards, but also by development choices, emissions and access to resilient livelihoods.
Emissions gaps and fair pathways
The UNEP Emissions Gap Report 2024 projects global greenhouse-gas emissions of 57 GtCO2e in 2030 under current policies, with a 53–59 GtCO2e range. That projection is about 2 GtCO2e above unconditional nationally determined contributions (NDCs), with a 0–3 GtCO2e range, and about 5 GtCO2e above conditional NDCs, with a 2–9 GtCO2e range.
The pathway gaps are larger at safer temperature levels. Closing the gap to a below-2°C pathway requires 14 GtCO2e less annual emissions in 2030 than implied by current unconditional NDCs. Closing the gap to a 1.5°C pathway requires 22 GtCO2e less. Full implementation of unconditional NDCs would reduce 2030 emissions by 4% compared with 2019; conditional NDCs would reduce them by 10%. The report’s pathway comparisons require a 28% reduction from 2019 emissions by 2030 for a 2°C-aligned pathway and a 42% reduction for a 1.5°C-aligned pathway.
For 2035, NDCs need reductions of 37% below 2019 levels for 2°C compatibility and 57% for 1.5°C compatibility. Continuation of current policies is estimated to produce maximum warming of 3.1°C this century, with a 1.9–3.8°C range. Full implementation of conditional NDCs lowers that maximum-warming projection to 2.6°C, with a 1.9–3.6°C range.
The report also identifies available mitigation potential. Existing technologies costing below US$200 per tonne of CO2e have an estimated mitigation potential of 31 GtCO2e per year in 2030 and 41 GtCO2e per year in 2035. Solar photovoltaics and wind account for 27% of the assessed total emission-reduction potential in 2030 and 38% in 2035. These figures describe assessed potential, not guaranteed reductions.
Adaptation finance and capacity
The UNEP Adaptation Gap Report 2024 found that 171 countries—87% of countries assessed—had at least one national adaptation planning instrument in 2024. Among those countries, 51% had a second instrument and 20% had a third. Planning coverage therefore does not mean that implementation capacity or finance is equal.
International public adaptation finance to developing countries rose from US$22 billion in 2021 to US$27.5 billion in 2022. Estimated adaptation-finance needs were US$215–387 billion per year, compared with the US$27.5 billion in international public flows in 2022. Even doubling adaptation finance from 2019 levels would reduce the adaptation finance gap by only about 5% in the report’s assessment of the 2025 goal.
The composition of finance also matters. Loans represented 62% of international public adaptation finance flows in 2022, and about one-quarter of those loans were non-concessional. More than 66% of estimated adaptation costs or finance needs fall in areas typically financed by the public sector. Support for technology-related adaptation efforts increased from US$5.7 billion in 2018 to US$12.7 billion in 2022, while agriculture received an average 31% of adaptation-related development finance per year during the assessed 2018–2022 period.
| Finance measure | Amount or share | Period |
|---|---|---|
| International public adaptation finance | US$27.5 billion | 2022 |
| Estimated annual adaptation-finance needs | US$215–387 billion | Annual estimate |
| Loans in international public adaptation finance | 62% | 2022 |
| Climate finance provided and mobilised by developed countries | US$115.9 billion | 2022 |
The OECD’s Aggregate trends: Climate Finance Provided and Mobilised by Developed Countries in 2013–2022 reports that developed countries provided and mobilised US$115.9 billion in climate finance for developing countries in 2022. The 2022 total was US$26.3 billion, or 30%, higher than in 2021. Public climate finance attributable to developed countries rose from US$38 billion in 2013 to US$91.6 billion in 2022, while private finance mobilised by public climate finance grew from US$14.4 billion in 2021 to US$21.9 billion in 2022.
These finance totals use the source reports’ definitions of provided, mobilised, public, private, adaptation and climate finance. They are not directly interchangeable. That distinction is central to interpreting climate justice statistics: a larger headline total does not automatically mean that the places facing the greatest risks received the scale, terms or type of support required.