The southwest monsoon of 2025 in India and Pakistan has emerged as the deadliest climate disaster of the year, claiming the highest number of lives among all major global climate events, according to a new report by UK-based charity Christian Aid. The monsoon season, which recorded rainfall eight per cent above normal, also ranked as the fifth most expensive climate disaster worldwide in terms of economic losses.
Published in London on December 27, the report titled Counting the Cost 2025 highlights how extreme weather events driven by climate change caused more than $120 billion in losses globally this year from just the ten most severe disasters. The South Asian monsoon alone caused estimated financial damages of $5.6 billion, or over ₹50,000 crore, across India and Pakistan.
Christian Aid noted that Asia accounted for four of the world’s six most expensive climate disasters in 2025. Flooding linked to the monsoon killed more than 1,860 people in India and Pakistan, making it the most fatal event of the year. The report warned that these figures largely reflect insured losses, meaning the true economic and human costs are likely much higher.
Climate experts and activists pointed directly to fossil fuel-driven warming as the underlying cause. Harjeet Singh, global climate activist and founding director of the Satat Sampada Climate Foundation, said the fingerprints of fossil fuels were visible across all major disasters of the year. From wildfire-hit regions in the United States to flooded plains of South Asia, he said, the common factor was a warming world driven by oil, gas and coal.
Sanjay Vashist, director of Climate Action Network South Asia, criticised developed countries, particularly the United States, for treating climate action as optional even as some of the world’s most expensive disasters struck their own territories. Two of the ten costliest disasters of 2025 occurred in the US, including the Palisades and Eaton wildfires in California, which together caused damages exceeding $60 billion.
According to the report, cyclones across Thailand, Indonesia, Sri Lanka, Vietnam and Malaysia ranked as the second most expensive disaster, causing losses of $25 billion. Extreme rainfall and flooding in China between June and August resulted in damages worth $11.7 billion. Category 5 hurricane Melissa, which devastated parts of the Caribbean in late October, caused losses of $8 billion, placing it fourth on the list, followed by the South Asian monsoon.
Christian Aid stressed that these disasters should not be seen as natural. Emeritus Professor Joanna Haigh of Imperial College London said they were the predictable outcome of continued fossil fuel expansion and political inaction. Christian Aid CEO Patrick Watt added that the poorest communities were suffering first and worst, and that the events of 2025 were a clear warning of what lies ahead without a rapid transition away from fossil fuels.
The monsoon’s impact was particularly severe due to its intensity and duration. India recorded its wettest May since records began, and by September had received rainfall that was eight per cent above average. According to the India Meteorological Department, the southwest monsoon delivered 108 per cent of its long-period average rainfall, making it one of the strongest monsoons in recent years and the second consecutive year of above-normal rainfall.
IMD Director Mrutyunjay Mohapatra said the stronger-than-normal monsoon followed predicted climate trends. Data showed that total rainfall between June and September stood at 937.2 millimetres, with excess or large excess rainfall recorded in 14 of the 18 monsoon weeks.
The Christian Aid report described widespread devastation across India and Pakistan, with early torrential rains triggering floods, landslides, cloudbursts and flash floods, particularly in mountainous regions. Rivers overflowed, farmlands were submerged, glacial melt intensified flooding and thousands of settlements were affected.
A separate assessment by the Centre for Science and Environment painted an even starker picture. According to CSE, India experienced extreme weather on 99 per cent of days during the first nine months of 2025. These events killed over 4,000 people, damaged nearly 9.5 million hectares of crops, destroyed close to one lakh houses and led to the deaths of almost 59,000 animals. During the monsoon alone, extreme weather occurred on all 122 days across 35 states and Union Territories, with Himachal Pradesh emerging as the worst-hit state.
Together, the findings underline how climate change is no longer a distant threat but a daily reality, with South Asia paying the highest human cost in 2025.