Human-caused climate change made the “unprecedented” wildfires that spread across Brazil’s Pantanal wetlands in June 2024 between four and five times more likely, according to a new rapid attribution study.
South America’s Pantanal – the world’s largest tropical wetland – experienced exceptionally hot, dry and windy conditions in June, causing blazes in the region to soar.
The World Weather Attribution (WWA) service finds that the month was the hottest, driest and windiest year in the 45-year record.
The team conducted an attribution study to find the “fingerprint” of climate change on these weather conditions.
They find that, in a world without climate change, these conditions would be very rare – occurring only once every 161 years.
In today’s climate, which has already warmed by 1.2C above pre-industrial temperatures as a result of human-caused warming, these conditions are a one-in-35 year event.
The authors also explore how wildfires in the region could continue to worsen as the planet warms.
They find that if that planet reaches warming levels of 2C, the likelihood of these conditions could double, to once every 18 years.
Soaring fires
The vast Pantanal wetland extends across Brazil, Bolivia and Paraguay.
It is one of the most biodiverse places on earth, home to more than 4,700 plant and animal species.
Every year, hot and dry weather conditions make the wetland prone to wildfires – usually between July and September.
By June this year, intense wildfires were already soaring. The number of Pantanal fires increased by 1,500% in the first half of this year compared to the same period in 2023, according to data from Brazil’s National Institute for Space Research reported by the Brasil de Fato newspaper.
This amounts to more than 1.3m hectares of the wetland burned so far this year – an area around eight times the size of London.
Around 2,500 fires were identified in June, which is the highest number since 1998 and more than six times the level reported in 2020, which was “known as the ‘year of flames,’ when wildfires ravaged the area and sparked widespread outcry”, the Associated Press said.
The region is currently experiencing its worst drought in 70 years, which Brazil’s government has said is being “intensified by climate change and one of the strongest El Niño phenomena in history”.
Prolonged dry periods, high temperatures and land-use change all contribute to wildfire conditions, says Dr Maria Lucia Barbosa, a postdoctoral researcher at the Federal University of São Carlos in Brazil, who was not involved in the attribution study. She tells Carbon Brief:
“While fires are a natural part of the Pantanal ecosystem, the recurrence of extreme fire seasons – such as the current one, shortly after the devastating 2020 fires – suggests that, alongside climate change, a new fire regime may be emerging in the ecosystem, characterised by increased severity and frequency.”
Hot, dry and windy
Wildfire intensity and duration are influenced by a wide range of factors, including weather, vegetation and fire management strategies.
The authors of the new study focus on a metric called the “daily severity rating” (DSR), which combines information on maximum temperature, humidity, wind speed and precipitation. Dr Clair Barnes – a research associate at Imperial College London’s Grantham Institute and author on the study – told a press briefing that this metric “indicates how difficult it is likely to be to control the fire once it starts”.
High temperatures and wind speeds, as well as low humidity and rainfall, are very conducive to wildfires spreading and, therefore, produce a high DSR.
The map below shows the average DSR in the Pantanal in June 2024. It reveals that most of the Pantanal was experiencing wildfire risk above the 1990-2020 average over that month.
The weather conditions in the Pantanal in June 2024 were “really unusual for the time of year”, Barnes said.
To investigate how atypical the weather conditions in June 2024 were, the authors analysed temperature, windiness, rainfall and humidity data from the past 45 years.
The chart below depicts annual average rainfall and annual average daily maximum temperature in the Pantanal over 1979-2024. It shows that over the past 45 years, the average temperature in the Pantanal has been steadily increasing and total rainfall has been decreasing.
The authors find that June 2024 was the hottest, least rainy and windiest June since records began. They also find that the relative humidity was the second lowest on record.
Annual rainfall across the Pantanal has been decreasing over the past 40 years, the authors note. They point out that natural variability and deforestation are known to impact rainfall patterns across South America, but add that climate change “may also be influencing the drying trend”.
Attribution
Attribution is a fast-growing field of climate science that aims to identify the “fingerprint” of climate change on extreme-weather events, such as heatwaves and droughts.
To conduct attribution studies, scientists use models to compare the world as it is today to a “counterfactual” world without human-caused climate change. In this study, the authors investigated the impact of climate change on DSR in the Pantanal region.
They find that in today’s climate – which has already warmed by 1.2C as a result of human activity – fire weather conditions like the ones that drove the wildfires in the Brazilian Pantanal during June 2024 are a “relatively rare event”, and would be expected to occur roughly once every 35 years.
However, they say, if the planet continues to warm, these events could become more likely. If the climate warms to 2C above pre-industrial levels, the likelihood of these fire conditions will double compared to today.
The graphic below shows how often June fire weather conditions, such as those seen in the Brazilian Pantanal in June 2024, could be expected under different warming levels.
The square on the left shows a world without climate change, in which these DSR levels would happen once every 161 years. The middle square shows that in today’s climate, the DSR is a one-in-35 year event. And the square on the right shows that in a 2C world, a June DSR like that of 2024 could be expected once every 18 years.
The authors also investigate how climate change affected DSR “intensity”. They find that human-induced warming from burning fossil fuels increased the June 2024 DSR by about 40%.
The authors add that as the climate continues to warm, this trend is likely to worsen. The authors warn that if warming reaches 2C above pre-industrial temperatures, similar June fire weather conditions will become 17% “more impactful”.
(These findings are yet to be published in a peer-reviewed journal. However, the methods used in the analysis have been published in previous attribution studies.)
Fire impacts
Wildfires have wide-ranging impacts on people and nature in the Pantanal. In one example, a 2021 study found that around 17m vertebrates were “killed immediately” by the fires in 2020.
Wildfires can “devastate [the] livelihoods” of people living in the Pantanal and “pose significant health risks” from the resulting smoke, Barbosa says.
She notes that wildfires release CO2 into the atmosphere, contributing to climate change, and they “lead to widespread loss of habitat, endanger wildlife and disrupt ecological balances”. She tells Carbon Brief:
“Species that are already threatened or have limited ranges are particularly vulnerable to habitat destruction caused by fires.
“Repeated fires can push fire-sensitive vegetation into a state of permanent degradation, further threatening the ecological integrity of the region.”
Some fires are permitted for agricultural purposes – such as to burn degraded pasture – during the rainy season, from around November to April. This practice is banned in the drier summer months, but a 2020 piece from Mongabay notes that “in reality, the ban is not always respected and enforcement is haphazard”.
Filippe Santos, a researcher at Portugal’s University of Évora and one of the authors of the study, told a press briefing that “fire is part of the dynamics” of the Pantanal – when it is controlled.
Low-intensity fires allow animals “time to leave” the area, he said, adding:
“What we see with wildfires, is that this does not happen, because the fire is so intense and on such a large scale that animals don’t have time to run away.”
The “highly intense” wildfires also “don’t give nature enough time to recover”, Santos says.
In June, Brazil’s environment minister, Marina Silva, told the government news agency Agencia Brasil that the country is “facing one of the worst situations ever seen in the Pantanal”, adding that the fires are heightened by climate extremes and criminal activities.
Most Pantanal fires are caused by human activity, a 2022 study found. Police in Brazil are investigating the “possible culprits” behind 18 fire outbreaks in the region, Silva said last month.
In recent weeks, a law to improve coordination on tackling fires took effect in Brazil.
A statement from the Institute for Society, Population and Nature, a Brazilian NGO, says this new policy is a “significant milestone” and will establish “guidelines for the practice of integrated fire management across all biomes and territories in the country”.
Barbosa says it will be a “challenge” to implement this policy. She would like to see a “comprehensive national early warning system for multiple hazards to ensure risk reduction” for a range of threats – including wildfires. She tells Carbon Brief:
“Collaboration with local communities, firefighters and brigades is crucial for prevention and response efforts…A coordinated approach that integrates all stakeholders, along with the establishment of a national fund dedicated to fire management, is essential for mitigating the impacts of future fire seasons.”
The post Climate change made the ‘supercharged’ 2024 Pantanal wildfires 40% more intense appeared first on Carbon Brief.
Climate change made the ‘supercharged’ 2024 Pantanal wildfires 40% more intense
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The planet is heating up more quickly than ever before.
For decades, greenhouse gas emissions caused by human activity have been building up in the atmosphere and trapping ever-higher levels of heat.
The resulting asymmetry between incoming solar energy and energy radiated back out into space – known as “Earth’s energy imbalance” – provides a direct measure of the extent to which humans are disrupting the Earth’s climate system.
This imbalance is growing and in 2025 its 10-year average reached a record high, indicating that global temperatures could increase at even higher rates in the future.
This is among the headline findings of the latest “indicators of global climate change” (IGCC) report, published in the journal Earth System Science Data, which tracks changes in the climate system on an annual basis.
The report, now in its fourth iteration, has been produced by dozens of scientists from around the world.
Its findings are designed to fill the gap between Intergovernmental Panel on Climate Change (IPCC) science reports, which are published every 5-7 years.
In this article, we unpack the IGCC report, which explores how human activity is driving a growing energy imbalance and why monitoring systems to track global climate are so crucial.
(For more on previous IGCC reports, see Carbon Brief’s coverage in 2023, 2024 and 2025.)
Greenhouse gas emissions remain at an all-time high
Global greenhouse gas emissions are continuing to increase, mostly as a result of the use of fossil fuels. However, deforestation, agriculture and industrial processes also play an important role.
Over the most recent decade (2015-24), emissions stood at the equivalent of 54.6bn tonnes of carbon dioxide equivalent (GtCO2e) per year. In 2024, the most recent year for which we have complete data, emissions reached 56.8GtCO2e.
As the chart below shows, these emissions have pushed up atmospheric levels of CO2, methane and nitrous oxide. In 2025, concentrations of these gases reached 425.6 parts per million (ppm), 1936.3 parts per billion (ppb) and 339.4ppb, respectively.
This represents a rise of 3.8%, 3.8% and 2.2%, respectively, since the 2019 levels reported in the IPCC’s sixth assessment report (AR6).
At the same time, declines in emissions of aerosols such as sulphur dioxide, partly as a result of efforts to tackle air pollution, are increasing the Earth’s energy imbalance. This is because aerosols have a cooling effect on the Earth’s climate, counteracting warming from CO2 and other greenhouse gas emissions.
(Tackling sulphur dioxide, alongside other particulate emissions, remains critical because the immediate health and environmental damage they cause far outweighs their short-term cooling effect on the climate.)
The Earth’s energy imbalance is rising rapidly
The Earth’s energy imbalance has long been recognised as a key indicator of how the climate is being affected by human activities.
However, it is only in the last few decades that scientists have been able to record temperature changes deep enough in the ocean to accurately quantify it.
Earth’s energy imbalance measures how quickly excess heat is accumulating in every part of the Earth system, primarily in the ocean, but also in land, ice and atmosphere.
Through this accumulation of heat, the energy imbalance influences the rate of sea level rise and ice melt across the world, as well as increasing the frequency and intensity of extreme weather events, such as storms, floods and droughts.
Without human influence, the Earth’s energy imbalance would be close to zero.
But, as greenhouse gas emissions have built up in the atmosphere, the imbalance has been growing since the 1970s. Recent increases to Earth’s energy imbalance have outpaced those projections made by climate models — indicating the planet could see more warming than expected in the future.
As the right-hand chart below shows, the imbalance is now at a record high, having more than doubled over the past two decades.
It has increased by around 40% since 2019, from an average 0.79 watts per square metre (Wm2) over 2006-18, according to IPCC AR6, to 1.12Wm2 over 2013-25.
The left-hand chart shows how heat is accumulating in the ocean (blues), ice (grey), land (orange) and atmosphere (purple).
Global temperature rise
The excess heat building up in the climate system from the energy imbalance is pushing up global temperatures at a record rate of 0.27C per decade.
We estimate that human-induced warming – the amount of observed global surface
temperature increase attributable to both the direct and indirect effects of human activities – reached 1.37C in 2025. This has risen from 1.0C in 2017, as reported in IPCC AR6.
While natural variability in the climate system – such as El Niño or La Niña events – can also influence temperatures year-to-year, the upward temperature trend we are seeing is being driven by the persistent imbalance in energy.
We now expect global temperatures to exceed the Paris Agreement limit of 1.5C above pre-industrial levels around the year 2030.
This is significant because 1.5C has been identified as the critical dividing line between manageable climate risks and catastrophic, potentially irreversible damage to global ecosystems and human societies.
Heat accumulating throughout the Earth system
While heat is accumulating throughout the Earth system, it is not being distributed evenly around the globe.
Since the 1970s, around 90% of this heat has been taken up by the ocean, affecting marine ecosystems, ocean circulation patterns, sea level rise and climate extremes.
For example, the number of marine heatwave days – periods of unusually high sea surface temperatures – has more than tripled globally since the early 1990s. The year 2025 alone saw 65 days of marine heatwaves – meaning they occurred, on average, more than one day a week.
Meanwhile, the cryosphere – the portion of the Earth made up of frozen water, including glaciers, ice sheets and permafrost – is experiencing widespread ice loss and thawing in response to the growing energy imbalance. This affects ecosystems, sea level rise and infrastructure in polar and high-latitude regions.
Rapid warming has also resulted in record extreme temperatures over land, with average maximum temperatures for any single day over 2016-25 around 1.92C above pre-industrial levels). This is an increase of almost half a degree compared to the previous decade (2006-15).
Sea level rise and the energy imbalance
Sea level rise provides one of the clearest long-term signals of a changing planet.
It is closely linked to Earth’s energy imbalance. As heat accumulates in the ocean, water expands, raising sea levels. Meanwhile, a warming land and atmosphere means addition of water to the oceans through melting of glaciers and ice sheets, also adding to sea level rise.
Over the long-term, sea levels have been rising, on average, at a rate of around 1.8mm per year since 1901, totalling a record 23cm in 2025. This is increasing the risk of coastal flooding, erosion and habitat loss in many low-lying areas around the world.
This rise can be seen in the left-hand chart below, which shows observed global sea level changes from tide gauges (grey and blue dashed lines) and satellites (red dashed lines) since 1901. The solid lines indicate the average across multiple datasets.
Sea level rise is accelerating consistent with the observed increase in Earth’s energy imbalance. Over 2006-25, sea levels have risen at a rate of 3.67mm per year – more than double the rate of 1.69mm per year seen over 1976-95.
This increasing rate is shown in the right-hand figure below, which shows four successive overlapping 20-year periods and the most-recent decade.
(Last year’s transition from El Niño to weak La Niña conditions affected global rainfall patterns and led to a small and temporary fall in global average sea level in 2025. This explains the slight decrease in rate of sea level rise for the most recent decade, which is affected more than the 20-year period 2006-25.)
The bigger picture
Despite greenhouse gas emissions not increasing as rapidly as in the 2000s, this year’s IGCC findings continue to show how far and how fast the climate is changing due to human activity.
A significant increase in decarbonisation efforts in the second half of this decade is required to slow down the rate of human-caused warming and limit the escalation of climate risks and impacts.
These findings, like many others produced by scientists across the globe, rely on international expertise, partnership and the maintenance and availability of global climate datasets and the global observing programmes that underpin them.
This year’s edition of IGCC used more than 40 global datasets produced by research teams around the world, including the NASA satellite record of the Earth’s energy imbalance and the ARGO deep ocean float network.
However, a number of long-term monitoring programmes could be threatened by funding decisions made by governments around the world, most notably the Trump administration in the US.
Local meteorological data and weather balloon measurement programmes in many countries have declined in recent years, especially in Africa, the west Pacific and South America. This reduces scientists’ ability to monitor and understand key indicators of climate change.
This is not just an issue for climate science. Many of these observations are key to weather forecasts and systems that provide early warning for extreme weather. For example, media reports have suggested that recent reductions in weather balloon measurements in Alaska led to a lack of warnings for a recent winter storm.
The continuity and integrity of the climate observations that scientists use to understand how the climate is changing depends on effective and sustained coordination by international organisations, such as the Global Climate Observing System, the World Meteorological Organization and World Climate Research Programme.
Without this data and its coordination, future assessments will be much more difficult at a time when urgent climate action is needed.
The post Guest post: How a record-high ‘energy imbalance’ is driving global warming appeared first on Carbon Brief.
Guest post: How a record-high ‘energy imbalance’ is driving global warming
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