The world is perilously close to 1.5ºC warming and the climate crisis is increasing the frequency and severity of disasters, with devastating consequences for the lives and livelihoods of millions of people. In 2023, global temperatures hit a record high and 2024 is expected to be even hotter. This extends a decade-long trend, with 2015 to 2024 now the hottest years recorded. In 2023, rivers worldwide had their driest year in over three decades, and ocean temperatures spiked, with 2024 data showing comparable levels of heating. When water is scarce, polluted or difficult to access, people’s food security can be undermined, their livelihoods may be eroded and conflict can follow. Meanwhile, sea levels hit their highest point in 2023; although they dipped slightly in 2024, the last decade saw sea levels rise at twice the rate of two decades ago. Rising sea levels and increasing tide heights put coastal and island communities at risk of more intense storm surges, coastal erosion and flooding. Glaciers in 2023 recorded the greatest ice loss with water displaced equivalent to five times the Dead Sea’s volume. Global humanitarian leadership have stated that keeping the global temperature rise to below 1.5°C is a top humanitarian priority and called for dramatically increased ambition in the new ‘nationally determined contributions.
Average temperature anomaly
Climate change is intensifying the severity of weather-related disasters and wreaking havoc on food systems. It has made events like the devastating Horn of Africa drought (2020 to 2023) at least 100 times more likely, and increased the likelihood and destructive power of major hurricanes, such as Hurricane Beryl in 2024, the strongest June hurricane ever recorded in the Atlantic. Hotter temperatures, more frequent and severe droughts, floods, storms and rising sea levels are disrupting food and water security, degrading the environment, damaging human health and livelihoods, and displacing millions of people. The climate crisis is wreaking havoc on food systems, with droughts causing over 65 per cent of agricultural economic damages in the past 15 years, worsening food insecurity, especially in areas reliant on smallholder farming. In early 2024, drought was estimated to have reduced corn production in Mexico by 20 to 40 per cent, while drought southern Africa led to a 42 per cent loss in cereal production in Zambia.
Southern province, Zambia
A woman sifts dried earth through her fingers in a farm field in Maambo village. Because the farming is rain-fed, the ongoing drought means that most of the crops failed, and communities have suffered major losses.
UNICEF/Terence SampaWeather-related disasters are affecting millions of people each year and uprooting many from their homes. In 2023, 363 weather-related disasters were recorded, affecting at least 93.1 million people and causing thousands of deaths. In the same year, disasters triggered 26.4 million internal displacements/movements with over three quarters caused by weather events. Although complete data for 2024 is not yet available, the year has already seen major weather events. Persistent heatwaves affected East Asia, the Mediterranean and Middle East, the United Sates of America, northern India and the Horn of Africa. In the first half of the year, Afghanistan faced cold waves and flooding, while floods caused major loss of life in east Africa, including Kenya and Tanzania. Lake Victoria’s record-high levels contributed to extensive flooding in South Sudan while the rising waters of Lake Tanganyika triggered severe flooding in both Burundi and the Democratic Republic of the Congo (DRC). Heavy rains caused devastating flooding in southern Brazil, forcing more than 400,000 people to leave their homes and leading to billions of dollars in economic losses. The North Atlantic hurricane season started early in 2024, with Hurricane Beryl setting a record as the earliest Atlantic Ocean category 5 storm. Extreme rainfall affected central Europe, and flooding in the Sahel in September displaced nearly 1.4 million people across Chad, Mali and Nigeria. Typhoon Yagi displaced nearly 1.6 million people across Myanmar, Lao People's Democratic Republic and Viet Nam in September 2024. Children are especially affected, with roughly one in eight significantly impacted by 10 major weather events in 2024, including the drought in Southern Africa, Typhoon Yagi in southeast Asia and flooding in the Sahel.
The climate crisis also threatens physical and mental health. The disruption of health care due to climatic events hinders effective humanitarian response, as seen in South Sudan, where floods submerged 58 health facilities. In 2024, El Niño intensified these challenges globally. Water-borne diseases like cholera and vector-borne illnesses such as malaria and dengue surged, driven by warmer temperatures and shifting rainfall patterns.
Hurricane Beryl devastates the Caribbean
In July 2024, Hurricane Beryl, one of the strongest storms on record, hit the Caribbean. Across Grenada and Saint Vincent and the Grenadines, homes, roads, health facilities and power infrastructure were damaged or destroyed. People needed immediate health, food, shelter, water, hygiene and relocation assistance.
There is also growing evidence that conflict can contribute directly to climate change. Researchers estimate that the emissions from the first 120 days of the conflict in Gaza were greater than the annual emissions of 26 individual countries and territories. The first seven months of Russia’s invasion of Ukraine were estimated to cause at least 100 million tonnes of carbon dioxide equivalent. While data is poor, estimates suggest that the world’s militaries are responsible for 5.5 per cent of global greenhouse gas emissions, not including emissions from warfighting itself. And vice-versa, climate change may also indirectly contribute to conflict by increasing tensions around food security, water scarcity and resource competition.
Meanwhile, the top 30 oil and gas companies (excluding those based in poorer countries) have recorded a combined average of $400 billion per year in free cash flow since the Paris agreement was signed in 2015. The UN Secretary-General has called for global production and consumption of all fossil fuels to be cut by at least thirty percent by 2030 and urged every country to ban advertising from fossil fuel companies.
Global humanitarian leadership have called for urgent support for communities on the frontlines of the climate crisis to adapt and respond to its impacts. Yet, climate finance for fragile and conflict-affected countries is critically lacking. These countries receive far less adaptation finance than other low-income countries, despite their acute vulnerability to climate change. Adaptation must be planned, financed and implemented at a scale and speed that matches the worsening climate crisis. Further, access to climate finance must be significantly increased and directed to the local level in countries experiencing conflict, extreme poverty and humanitarian crises, including least developed countries (LDCs) and small island developing States (SIDS). Humanitarian leadership has also called for climate finance processes to be streamlined and made more accessible to multiple actors, including civil societies and community-based organizations.
Flooding in South Sudan puts lives and livelihoods in peril
In September 2024, floodwaters devastated homes and livelihoods, affecting more than 735,000 people. Many of the affected areas were already grappling with the impacts of conflict, displacement and acute hunger.
Disaster risk reduction and early warning systems are crucial to helping communities prepare for, and respond to, the climate crisis, and anticipatory action can help humanitarians respond early. One third of people, mainly in LDCs and SIDS, lack effective early warning systems for climate-related disasters. Urgent new investments are needed to improve and extend early warning, in support of the Secretary General’s Early Warnings for All initiative. Early warning systems must cover those most at-risk, particularly in countries and communities affected by conflict, fragility and/or humanitarian crises, and enable enhanced climate risk appraisal and impact management interventions, particularly scaled-up anticipatory action.
As this year’s GHO highlights, without urgent climate action, there are a growing number of countries that face increasingly frequent and severe disasters. Seven countries began 2025 with humanitarian Flash Appeals that should be on a development trajectory, but risk facing repeated crises without global support to help their communities adapt and prepare. And in some of the world’s largest humanitarian crises, people are now faced with rising climate risks: the 2020 to 2023 Horn of Africa drought took a devastating toll on communities previously hit by conflict in Somalia, and flooding in South Sudan has affected about 1.4 million people in 2024, mostly in parts of the country that have endured intense fighting. At least 90 million displaced people are living in countries with high-to-extreme exposure to climate-related hazards and nearly half out of all forcibly displaced people are bearing the burden of both conflict and the adverse effects of climate change. It is therefore critical that the world acts to support those on the frontlines of the climate crisis, including redirecting climate finance to those who need it most, before it is too late.
Urbanization exacerbates climate vulnerability
Urbanization both drives and heightens vulnerabilities from, climate change. Cities contribute a growing share of global greenhouse gas emissions, rising from about 62 per cent in 2015 to between 67 and 72 per cent in 2020. The concentration of people and activities in urban areas amplifies local warming, intensifies heat extremes and increases precipitation and runoff. At the same time, the climate crisis adversely affects urban residents’ health, livelihoods and essential infrastructure.
Both rapid- and slow-onset climate events disrupt urban transportation, energy, water, food and sanitation systems, leading to economic damages, service interruptions and decreased quality of life, with marginalized groups bearing the greatest burden. As urbanization rises in coastal and low-lying areas, exposure to extreme river flow and sea level rise will increase, with informal and rapidly growing settlements facing the highest risks.
To improve urban resilience, access to disaster risk reduction finance is essential, particularly for economically and socially vulnerable populations, including those in informal settlements.