Record-breaking sea temperatures across the Gulf of Mexico have been a key ingredient behind some of the intense hurricanes devastating the region this year.
Last month, Hurricane Helene made landfall on Florida’s “Big Bend” and then stalled over several states to the north dumping “enormous rainfall totals”, resulting in epic flooding which killed at least 220 people.
Just a couple of weeks later, Milton – the ninth hurricane to form in the Atlantic this year and one of the most rapidly intensifying hurricanes on record – has swept this week towards Florida’s Tampa Bay region, threatening communities that are still recovering from Helene’s impact.
A rapid attribution study recently concluded that record-breaking ocean temperatures in the Gulf of Mexico, which helped Hurricane Helene to “spin up”, were made 200-500 times more likely because of human-caused climate change.
Scientists tell Carbon Brief that the same intense ocean heat likely helped to fuel Milton’s behaviour and explains how hurricanes can become more intense in a fast warming world.
How do hot oceans fuel hurricanes?
A hurricane is the name for a tropical cyclone that forms in the Atlantic Ocean or northeastern Pacific Ocean.
Atlantic hurricanes typically first form over the tropical waters of the north Atlantic off the African continent. As the systems travel westwards across the Atlantic, they draw up the warm, moist air that rises from the surface of the ocean, using it to fuel themselves and grow stronger.
As the low-pressure system picks up energy, winds can begin to spin, forming a storm. The warmer the ocean water is, the more energy the storm accumulates and the more quickly it can intensify. Sea surface temperatures of more than 26.5C down to a depth of 50 metres can drive the storm to intensify into a hurricane, once wind speeds exceed 74 miles per hour.
The 2024 Atlantic season runs from the start of June to the end of November and has already seen multiple intense storms, including the powerful Helene and Milton hurricanes, which have struck Florida within just two weeks of each other.
Both hurricanes picked up energy as they travelled over the Gulf of Mexico, which is currently experiencing a marine heatwave.
The graph below shows the extra ocean heat content – a metric that captures the amount of thermal energy stored in the water – for the Gulf of Mexico. For each month, it shows the extra ocean heat, compared with the average amount for that month during 2013-23.
A tropical storm is said to undergo “rapid intensification” if its wind speed increases by at least 35mph over a 24-hour period. Hurricane Milton’s wind speed accelerated faster than all but two previously recorded storms, with more than a 90mph increase in speeds in just 24 hours, ranking it as one of the “strongest” Atlantic storms ever recorded.
A study published in August in the Nature journal Communications Earth & Environment examined hurricanes that form over the Gulf of Mexico. It found that “rapid intensification” is 50% more likely to occur during marine heatwaves.
A rapid attribution study by Climate Central indicates that, over the past two weeks, the record-breaking temperatures in the Gulf of Mexico were made 400-800 times more likely by climate change.
Dr Kevin Reed – a researcher from Stony Brook University in New York – tells Carbon Brief that “Hurricane Milton’s rapid intensification this week is a telltale sign of climate change, which is responsible – in part – for the near-record temperatures in the Gulf of Mexico currently”. He adds:
“Warmer ocean temperatures are leading to more storms that undergo rapid intensification leading to an increase in the proportion of storms that reach major hurricane strength.”
A rapid attribution study from the World Weather Attribution (WWA) service examining Hurricane Helene used a model to investigate its strong winds by analysing storms making landfall within two degrees (120 nautical miles) of Helene. It said:
“By statistically modelling storms in a 1.3C cooler climate, this model showed that climate change was responsible for an increase of about 150% in the number of such storms (now once every 53 years on average, up from every 130 years) and, equivalently, that the maximum wind speeds of similar storms are now about 6.1 m/s (around 11%) more intense.”
The same team is now conducting a rapid analysis on the influence of climate change on Hurricane Milton, which will be released on Friday.
“This is in line with other scientific findings that Atlantic tropical cyclones are becoming wetter under climate change and undergoing more rapid intensification,” the WWA study on Helene finds.
Dr Kerry Emanuel, a professor of meteorology at the Massachusetts Institute of Technology, tells Carbon Brief that “Milton’s behaviour is consistent with predictions that hurricane scientists have made going back at least three decades”.
New normal?
Since 1878, around six to seven hurricanes, on average, have formed in the North Atlantic every year, with only a couple typically making landfall in the US.
The number of Atlantic hurricanes on record has increased over the period 1851-2019. However, some research suggests that more consistent monitoring, rather than a true increase in hurricane numbers, is behind this trend.
There is a clearer trend of increasing hurricane intensity. Research shows that the proportion of tropical cyclones reaching at least category 3 intensity has also risen over the past four decades. Although the study does not confidently link this increase to climate change, it notes that higher sea surface temperatures are likely to contribute.
As Prof Andrew Dessler summarises on his Climate Brink blog, the impact of climate change on the intensity and frequency of tropical cyclones is still not certain. However, he says that “we can have high confidence that climate change will drive more intense hurricanes”.
Meanwhile, studies have shown that the record-breaking 2020 Atlantic hurricane season, when 14 hurricanes were recorded, was partly due to increased sea surface temperatures.
A study published by Nature Communications in 2022 found that human-caused climate change increased sea surface temperatures in the North Atlantic basin by 0.4-0.9C. The authors estimated that this increased “extreme three-hourly storm rainfall rates” and “extreme three-day accumulated rainfall amounts” for Atlantic storms by 11% and 8%, respectively.
Another 2022 study published in Nature Communications found that over the period 1982-2020, climate change-induced increases in sea surface temperatures doubled the probability of “extremely active tropical cyclone seasons”. The 2020 season might have been made twice as likely by ocean surface warming, the authors found.
The post Explainer: How hotter oceans can fuel more intense Atlantic hurricanes appeared first on Carbon Brief.
Explainer: How hotter oceans can fuel more intense Atlantic hurricanes
Climate Change
DeBriefed 15 August 2025: Raging wildfires; Xi’s priorities; Factchecking the Trump climate report
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Blazing heat hits Europe
FANNING THE FLAMES: Wildfires “fanned by a heatwave and strong winds” caused havoc across southern Europe, Reuters reported. It added: “Fire has affected nearly 440,000 hectares (1,700 square miles) in the eurozone so far in 2025, double the average for the same period of the year since 2006.” Extreme heat is “breaking temperature records across Europe”, the Guardian said, with several countries reporting readings of around 40C.
HUMAN TOLL: At least three people have died in the wildfires erupting across Spain, Turkey and Albania, France24 said, adding that the fires have “displaced thousands in Greece and Albania”. Le Monde reported that a child in Italy “died of heatstroke”, while thousands were evacuated from Spain and firefighters “battled three large wildfires” in Portugal.
UK WILDFIRE RISK: The UK saw temperatures as high as 33.4C this week as England “entered its fourth heatwave”, BBC News said. The high heat is causing “nationally significant” water shortfalls, it added, “hitting farms, damaging wildlife and increasing wildfires”. The Daily Mirror noted that these conditions “could last until mid-autumn”. Scientists warn the UK faces possible “firewaves” due to climate change, BBC News also reported.
Around the world
- GRID PRESSURES: Iraq suffered a “near nationwide blackout” as elevated power demand – due to extreme temperatures of around 50C – triggered a transmission line failure, Bloomberg reported.
- ‘DIRE’ DOWN UNDER: The Australian government is keeping a climate risk assessment that contains “dire” implications for the continent “under wraps”, the Australian Financial Review said.
- EXTREME RAINFALL: Mexico City is “seeing one of its heaviest rainy seasons in years”, the Washington Post said. Downpours in the Japanese island of Kyushu “caused flooding and mudslides”, according to Politico. In Kashmir, flash floods killed 56 and left “scores missing”, the Associated Press said.
- SOUTH-SOUTH COOPERATION: China and Brazil agreed to “ensure the success” of COP30 in a recent phone call, Chinese state news agency Xinhua reported.
- PLASTIC ‘DEADLOCK’: Talks on a plastic pollution treaty have failed again at a summit in Geneva, according to the Guardian, with countries “deadlocked” on whether it should include “curbs on production and toxic chemicals”.
15
The number of times by which the most ethnically-diverse areas in England are more likely to experience extreme heat than its “least diverse” areas, according to new analysis by Carbon Brief.
Latest climate research
- As many as 13 minerals critical for low-carbon energy may face shortages under 2C pathways | Nature Climate Change
- A “scoping review” examined the impact of climate change on poor sexual and reproductive health and rights in sub-Saharan Africa | PLOS One
- A UK university cut the carbon footprint of its weekly canteen menu by 31% “without students noticing” | Nature Food
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
Factchecking Trump’s climate report
A report commissioned by the US government to justify rolling back climate regulations contains “at least 100 false or misleading statements”, according to a Carbon Brief factcheck involving dozens of leading climate scientists. The report, compiled in two months by five hand-picked researchers, inaccurately claims that “CO2-induced warming might be less damaging economically than commonly believed” and misleadingly states that “excessively aggressive [emissions] mitigation policies could prove more detrimental than beneficial”80
Spotlight
Does Xi Jinping care about climate change?
This week, Carbon Brief unpacks new research on Chinese president Xi Jinping’s policy priorities.
On this day in 2005, Xi Jinping, a local official in eastern China, made an unplanned speech when touring a small village – a rare occurrence in China’s highly-choreographed political culture.
In it, he observed that “lucid waters and lush mountains are mountains of silver and gold” – that is, the environment cannot be sacrificed for the sake of growth.
(The full text of the speech is not available, although Xi discussed the concept in a brief newspaper column – see below – a few days later.)
In a time where most government officials were laser-focused on delivering economic growth, this message was highly unusual.
Forward-thinking on environment
As a local official in the early 2000s, Xi endorsed the concept of “green GDP”, which integrates the value of natural resources and the environment into GDP calculations.
He also penned a regular newspaper column, 22 of which discussed environmental protection – although “climate change” was never mentioned.
This focus carried over to China’s national agenda when Xi became president.
New research from the Asia Society Policy Institute tracked policies in which Xi is reported by state media to have “personally” taken action.
It found that environmental protection is one of six topics in which he is often said to have directly steered policymaking.
Such policies include guidelines to build a “Beautiful China”, the creation of an environmental protection inspection team and the “three-north shelterbelt” afforestation programme.
“It’s important to know what Xi’s priorities are because the top leader wields outsized influence in the Chinese political system,” Neil Thomas, Asia Society Policy Institute fellow and report co-author, told Carbon Brief.
Local policymakers are “more likely” to invest resources in addressing policies they know have Xi’s attention, to increase their chances for promotion, he added.
What about climate and energy?
However, the research noted, climate and energy policies have not been publicised as bearing Xi’s personal touch.
“I think Xi prioritises environmental protection more than climate change because reducing pollution is an issue of social stability,” Thomas said, noting that “smoggy skies and polluted rivers” were more visible and more likely to trigger civil society pushback than gradual temperature increases.
The paper also said topics might not be linked to Xi personally when they are “too technical” or “politically sensitive”.
For example, Xi’s landmark decision for China to achieve carbon neutrality by 2060 is widely reported as having only been made after climate modelling – facilitated by former climate envoy Xie Zhenhua – showed that this goal was achievable.
Prior to this, Xi had never spoken publicly about carbon neutrality.
Prof Alex Wang, a University of California, Los Angeles professor of law not involved in the research, noted that emphasising Xi’s personal attention may signal “top” political priorities, but not necessarily Xi’s “personal interests”.
By not emphasising climate, he said, Xi may be trying to avoid “pushing the system to overprioritise climate to the exclusion of the other priorities”.
There are other ways to know where climate ranks on the policy agenda, Thomas noted:
“Climate watchers should look at what Xi says, what Xi does and what policies Xi authorises in the name of the ‘central committee’. Is Xi talking more about climate? Is Xi establishing institutions and convening meetings that focus on climate? Is climate becoming a more prominent theme in top-level documents?”
Watch, read, listen
TRUMP EFFECT: The Columbia Energy Exchange podcast examined how pressure from US tariffs could affect India’s clean energy transition.
NAMIBIAN ‘DESTRUCTION’: The National Observer investigated the failure to address “human rights abuses and environmental destruction” claims against a Canadian oil company in Namibia.
‘RED AI’: The Network for the Digital Economy and the Environment studied the state of current research on “Red AI”, or the “negative environmental implications of AI”.
Coming up
- 17 August: Bolivian general elections
- 18-29 August: Preparatory talks on the entry into force of the “High Seas Treaty”, New York
- 18-22 August: Y20 Summit, Johannesburg
- 21 August: Advancing the “Africa clean air programme” through Africa-Asia collaboration, Yokohama
Pick of the jobs
- Lancaster Environment Centre, senior research associate: JUST Centre | Salary: £39,355-£45,413. Location: Lancaster, UK
- Environmental Justice Foundation, communications and media officer, Francophone Africa | Salary: XOF600,000-XOF800,000. Location: Dakar, Senegal
- Politico, energy & climate editor | Salary: Unknown. Location: Brussels, Belgium
- EnviroCatalysts, meteorologist | Salary: Unknown. Location: New Delhi, India
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.
The post DeBriefed 15 August 2025: Raging wildfires; Xi’s priorities; Factchecking the Trump climate report appeared first on Carbon Brief.
DeBriefed 15 August 2025: Raging wildfires; Xi’s priorities; Factchecking the Trump climate report
Climate Change
New York Already Denied Permits to These Gas Pipelines. Under Trump, They Could Get Greenlit
The specter of a “gas-for-wind” compromise between the governor and the White House is drawing the ire of residents as a deadline looms.
Hundreds of New Yorkers rallied against new natural gas pipelines in their state as a deadline loomed for the public to comment on a revived proposal to expand the gas pipeline that supplies downstate New York.
New York Already Denied Permits to These Gas Pipelines. Under Trump, They Could Get Greenlit
A “critical assessment” report commissioned by the Trump administration to justify a rollback of US climate regulations contains at least 100 false or misleading statements, according to a Carbon Brief factcheck involving dozens of leading climate scientists.
The report – “A critical review of impacts of greenhouse gas emissions on the US climate” – was published by the US Department of Energy (DoE) on 23 July, just days before the government laid out plans to revoke a scientific finding used as the legal basis for emissions regulation.
The executive summary of the controversial report inaccurately claims that “CO2-induced warming might be less damaging economically than commonly believed”.
It also states misleadingly that “excessively aggressive [emissions] mitigation policies could prove more detrimental than beneficial”.
Compiled in just two months by five “independent” researchers hand-selected by the climate-sceptic US secretary of energy Chris Wright, the document has sparked fierce criticism from climate scientists, who have pointed to factual errors, misrepresentation of research, messy citations and the cherry-picking of data.
Experts have also noted the authors’ track record of promoting views at odds with the mainstream understanding of climate science.
Wright’s department claims the report – which is currently open to public comment as part of a 30-day review – underwent an “internal peer-review period amongst [the] DoE’s scientific research community”.
The report is designed to provide a scientific underpinning to one flank of the Trump administration’s plans to rescind a finding that serves as the legal prerequisite for federal emissions regulation. (The second flank is about legal authority to regulate emissions.)
The “endangerment finding” – enacted by the Obama administration in 2009 – states that six greenhouse gases are contributing to the net-negative impacts of climate change and, thus, put the public in danger.
In a press release on 29 July, the US Environmental Protection Agency said “updated studies and information” set out in the new report would “challenge the assumptions” of the 2009 finding.
Carbon Brief asked a wide range of climate scientists, including those cited in the “critical review” itself, to factcheck the report’s various claims and statements.
The post Factcheck: Trump’s climate report includes more than 100 false or misleading claims appeared first on Carbon Brief.
https://www.carbonbrief.org/factcheck-trumps-climate-report-includes-more-than-100-false-or-misleading-claims/
DeBriefed 15 August 2025: Raging wildfires; Xi’s priorities; Factchecking the Trump climate report
New York Already Denied Permits to These Gas Pipelines. Under Trump, They Could Get Greenlit
DeBriefed 15 August 2025: Raging wildfires; Xi’s priorities; Factchecking the Trump climate report
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