The number of people displaced within their own countries by natural disasters and extreme weather events rose sharply last year, according to a study commissioned by Greenpeace and conducted by the University of Hamburg.
The study found that 13.6 million people were internally displaced by natural disasters and extreme weather in 2025, up from 9.9 million the previous year.
The figures are based on data from the Internal Displacement Monitoring Centre (IDMC), a leading organization tracking displacement worldwide. Internally displaced people are those forced to flee their homes but who remain within their country's borders.
According to the study released on Friday, climate change is increasing both the frequency and intensity of weather-related extreme events, with people in the Global South particularly affected.
The report also found that war and violence have reached their highest levels since the end of World War II.
At the same time, the global budget for development cooperation and humanitarian assistance in 2025 was cut by nearly a quarter, or $175 billion, compared with the previous year.
As a result, an estimated 82.2 million people worldwide were living away from their home communities last year, compared with 83.5 million in 2024, the study said.
The report highlighted Afghanistan as an example of the overlapping pressures driving displacement.
According to the study, melting Himalayan glaciers are threatening drinking water supplies and agricultural irrigation in the country. Periods of extreme drought have been followed by devastating flash floods, forcing people to leave their homes.
Kabul could become the first major city in the world to run out of drinking water, the report said, echoing previous warnings from other groups.
"Afghanistan is among the countries most severely affected by the consequences of climate change. The country is also frequently struck by earthquakes," the study said.
The population is also coping with the legacy of decades of war, political instability and fragile economic conditions it added.
"While families in the Global South are losing their homes to climate disasters, wealthy nations are cutting aid budgets," Greenpeace Germany migration expert Fawad Durrani said.
Industrialized countries must reduce their emissions more quickly and invest more in helping vulnerable countries adapt to the impacts of climate change, he said.
