In 2025, greenhouse gas emissions produced by human activities turned what should have been a cooler year into one of the hottest ever, fuelling more dangerous and frequent heatwaves, droughts, storms and wildfires, climate scientists said in an annual report.

Planet-heating emissions primarily caused by burning fossil fuels pushed temperatures this year to “extremely high” levels, worsening extreme weather with devastating consequences – especially for the world’s most vulnerable, concluded scientists working with the World Weather Attribution (WWA) group.

Despite the return of La Niña – a climate pattern linked to large-scale cooling of the Pacific Ocean, which can temporarily bring milder global temperatures – the EU monitoring service Copernicus has said 2025 is “virtually certain” to end as the second- or third-warmest year on record.

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In its report released on Tuesday, the WWA research group found that climate change made 17 of the 22 extreme weather events it assessed this year more severe or more likely, while its remaining studies were inconclusive, mostly due to a lack of weather data from remote areas.

Ranging from heatwaves in South Sudan and Western Europe to extreme rainfall in Southeast Asia and wildfires in Los Angeles, those disasters killed thousands of people and displaced millions from their homes.

11 extra hot days since Paris Agreement

Theodore Keeping, a researcher at Imperial College London, said the catastrophic wildfires, record-breaking rainfall, unprecedented temperatures and devastating hurricanes seen in the last 12 months provide “undeniable evidence” of a rapidly changing global environment.

“We are living in the climate that scientists warned about a decade ago, when the Paris Agreement was signed,” he added.

Since the landmark accord was adopted in 2015, global average temperatures have risen by about 0.3C, and the world now experiences an average of 11 additional hot days each year, according to WWA’s research.

For the first time, global average temperatures over the last three years are on track to exceed 1.5C, the most ambitious goal governments agreed in Paris, according to the EU’s Copernicus service. The UK’s Met Office expects 2026 to be between 1.34C and 1.58C hotter than preindustrial levels.

“The continuous rise in greenhouse gas emissions has pushed our climate into a new, more extreme state, where even small increases in global temperatures now trigger disproportionately severe impacts,” said Sjoukje Philip, a researcher at the Royal Netherlands Meteorological Institute (KNMI). “We are entering a new era of climate extremes, where what was once an anomaly is quickly becoming the norm,” she added.

Silent-killer heatwaves

While heatwaves don’t leave a visible trail of destruction and often go underreported, the research group found they were the deadliest extreme weather event of 2025. One study estimated that climate change more than tripled the number of deaths caused by searing temperatures recorded across Europe this summer.

In South Sudan, extreme heat forced schools to close for two weeks in February 2025 after dozens of children collapsed with heatstroke. Human-made climate change made that heatwave 4C hotter and transformed an exceptionally rare event into a common one, now expected to happen every other year in South Sudan, a WWA assessment found.

Keeping of Imperial said the impacts are disproportionately shouldered by women and girls who predominantly work in sectors with high heat exposure such as agriculture and street-vending.

Flood risks rise as adaptation limits near

Floods were the disasters most studied by the WWA team in 2025, with devastating downpours made worse by climate change hitting Pakistan, Sri Lanka and Indonesia, the Mississippi River Valley in the US and Botswana.

In the Southern African nation, spells of extreme rainfall are becoming more frequent within a single year, while the rapid expansion of urban centres without adequate infrastructure upgrades makes them more susceptible to severe flooding, according to WWA.

The research group said this underscores the urgency of investing in measures to adapt to a warming world which can prevent many deaths and widespread destruction but remain critically underfunded.

However, the scientists also warned that even strong efforts to prepare for disasters cannot prevent all impacts, as climate change is already pushing millions close to the “limits of adaptation”.

“Jamaica was in a state of preparedness for Hurricane Melissa five days before landfall,” noted Keeping, “but when such an intense storm hits a small island nation in the Caribbean, even high levels of preparedness cannot prevent extreme losses and damages”.

Fossil fuel dependency is “costing lives”

Hurricane Melissa caused an estimated $8.8 billion in physical damage in Jamaica, equal to 41% of the country’s 2024 GDP, with only a small share of the losses expected to be covered by innovative insurance schemes.

In their report, WWA researchers said that drastically reducing fossil fuel emissions remains the key policy to prevent the worst climate impacts.

“Decision-makers must face the reality that their continued reliance on fossil fuels is costing lives, billions in economic losses, and causing irreversible damage to communities worldwide,” said Friederike Otto, WWA’s co-founder.

The post “New era of climate extremes” as global warming fuels devastating impacts in 2025 appeared first on Climate Home News.

“New era of climate extremes” as global warming fuels devastating impacts in 2025