Scientists have challenged the conclusions of a new study suggesting that the planet has already exceeded the 1.5C warming threshold set under the Paris Agreement.
Climate change is typically measured as the average global temperature increase relative to a “pre-industrial baseline”. The UN Intergovernmental Panel on Climate Change (IPCC), for example, uses the average temperature over 1850-1900 as their historical baseline. The planet has already warmed by around 1.2C compared to this period.
The new study, published in Nature Climate Change, uses proxy data from sea sponges in the Caribbean Sea to create a record of ocean temperatures from 1700 to the present day. This data suggests that warming started 40 years before the IPCC’s pre-industrial baseline period began.
Based on this new record, the authors say “warming is 0.5C higher than IPCC estimates”.
This means that “the global warming clock for emission reductions to minimise the risk of dangerous climate change has been brought forward by at least a decade”, the lead author told a press briefing.
However, many experts have warned that the framing of the study is misleading, arguing that the finding has no bearing on the Paris Agreement 1.5C limit, because it specifically “describes temperature rise relative to the late 19th century”.
Prof Richard Betts, head of climate impacts research at the UK Met Office Hadley Centre, who was not involved in the study, tells Carbon Brief that, crucially, the study “does not mean that impacts of climate change will occur earlier than expected”.
Other experts raised doubts that the 0.5C warming in the 1800s is human-caused, while many cautioned that proxy data from a single location should not be used to make assumptions about the entire planet.
The University of Oxford’s Prof Yadvinder Malhi, who was also not involved in the study, cautions that “the way these findings have been communicated is flawed, and has the potential to add unnecessary confusion to public debate on climate change”.
Shifting baselines
Humans have been releasing greenhouse gases into the atmosphere for centuries, causing global temperatures to rise.
In IPCC reports – considered the most authoritative summaries on climate science – scientists use a combination of land surface air temperatures and sea surface temperatures to assess changes in global mean surface temperatures (GMST).
The UN body reports global warming against a “pre-industrial baseline” of 1850-1900. It describes this baseline as “a pragmatic choice based upon data availability considerations” – in part because much of the observed climate data they use is only available from 1850.
For example, the Met Office’s HadSST4 dataset – one of the three datasets used in IPCC estimates of sea surface temperatures – goes back as far as 1850.
The IPCC also recognises that “both anthropogenic and natural changes to the climate occurred” before the 1850-1900 baseline. For example, in its 2021 report on climate science, the IPCC estimates that between 1750 and 1850-1900, GMST increased by around 0.1C. Of this, human activity was responsible for 0.0-0.2C, it says.
Nonetheless, researchers have typically followed suit in using the 1850-1900 average as their “pre-industrial baseline” to measure global warming.
In 2015, countries agreed under the Paris Agreement to hold the increase in the global average temperature to well below 2C above pre-industrial levels and pursue efforts to limit warming to 1.5C. “Pre-industrial” was not clearly defined in the agreement, but it has generally been taken to mean the average temperature over 1850-1900.
However, some scientists argue that the “pre-industrial baseline” period should begin before 1850.
The new study uses proxy data taken from sea sponges from the Caribbean sea, to present a timeseries of regional ocean temperatures from 1700 to the present day. Scientists collected sclerosponges from the ocean mixed layer – a region of ocean where heat is exchanged between the atmosphere and the ocean interior.
Between 1700-90 and 1840-60, the proxy data shows ocean warming of around 0.9C, according to the study. In the intervening time, there was some cooling, largely caused by volcanic eruptions, the authors say.
The plot below shows the proxy data (blue) from the year 1770, alongside the HadSST4 observed temperature record (purple), which begins in 1850, relative to a 1961-90 reference period. The authors have applied a 0.9C “offset” to their proxy data to account for pre-industrial temperature increase.
By comparing their proxy data against existing records of global temperature changes, the authors find “strong empirical evidence that the Caribbean ocean mixed layer has warmed proportionately to the average global increase in sea surface temperature, over the last ~50 years”.
The authors assume that the 0.9C offset “can be applied to land-air as well as the ocean mixed layer anomalies”, therefore concluding that GMST increased by 0.9C between 1700-1860 and 1961-90.
Meanwhile, global ocean temperatures measured using HadSST4 show only 0.4C of warming relative to the IPCC’s 1850-1900 pre-industrial period.
As such, the authors suggest that human-caused warming to date is actually 0.5C higher than IPCC estimates.
Dr Malcolm McCulloch – an emeritus professor at the University of Western Australia and lead author on the study – told a press briefing that, according to his study, the 1.5C Paris temperature threshold has already been crossed in around 2010-12.
He continued:
“It means that now, temperatures are at least 1.7C above the pre-industrial level. It also means that the 2C target will be passed in late 2020 unless there are major reductions in emissions…
“The big picture is that the global warming clock for emission reductions to minimise the risk of dangerous climate change has been brought forward by at least a decade”.
However, many scientists are concerned about this framing of the study.
Warming limits
Dr Friederike Otto, who was not involved in the study, is a senior lecturer in climate science at Imperial College London’s Grantham Institute. She says the paper “does not tell us anything about whether we have exceeded the 1.5C temperature limit set in the Paris Agreement”.
She continues:
“That limit was established as the threshold of unacceptably dangerous warming and describes temperature rise relative to the late 19th century. If this study has indeed identified warming from before the mid-1800s, that doesn’t mean the planet is any closer to breaking the 1.5C limit as it is widely understood.”
(The IPCC best estimate – in all but the highest emission scenario – is that global warming will pass 1.5C in the first half of the 2030s.)
Mahli adds:
“Our models of climate warming impacts are based on warming relative to 1850-1900 and moving the baseline definition of pre-industrial does not make these expected impacts worse…
“It is the date of the reference period that matters rather than whether it is labelled pre-industrial or not. The period 1850-1900 is a period of relatively reliable global data when industrial era human-caused climate change was likely negligible.”
Dr Andrew King is a senior lecturer in climate science at the University of Melbourne and was not involved in the study. He tells Carbon Brief that the findings of the study do not have any implications for the Paris Agreement warming limits, because these were “written in 2015 with a view to limiting further global warming from that point onwards”.
He adds:
“While the lack of clarity on what pre-industrial means was problematic, it doesn’t really affect that goal or any of the analyses on climate impacts at global warming levels that have been performed.”
King also tells Carbon Brief that the authors have not demonstrated that pre-1850s warming is due to human activity.
Malhi agrees that “this early industrial-era warming, if real, is almost certainly not human-caused”. He notes that human-caused emissions over 1750-1900 account for only 2.5% of total emissions to date, and says they are “unlikely to have caused substantial warming compared to the 1.4C of warming caused by the remaining 97.5% of cumulative emissions”.
Dr Duo Chan, a lecturer in climate sciences at the University of Southampton, also advises “caution” when interpreting the results, noting that “this new warming estimate does not align” with historical estimates of the different factors that affect the climate.
He notes that, according to Berkeley Earth temperature estimates, the land warmed by around 0.05C per decade over 1850-1900. The new proxy data from the sponges suggests that the ocean warmed almost twice as quickly as the land over this time – a “puzzling observation given the ocean warms more slowly than land”, he says.
Dr Zeke Hausfather, Carbon Brief’s contributing science writer, adds that the study authors are “conflating ocean mixed layer temperature with sea surface temperature in a way that is confusing”. He adds that “their reconstruction also seems a bit at odds with other palaeoclimate reconstructions – such as PAGES2k – that do not see large differences in pre-1900 temperatures”.
The sclerosponge record
Coralline sclerosponges are an ancient type of calcifying sea sponge which can live for hundreds of years. As they grow, chemicals called strontium and calcium build up in their skeletons. The ratio of strontium to calcium in their skeletons is higher during warm periods and lower during cool periods.
Scientists collected live specimens of sclerosponge from the Caribbean sea and analysed the ratios of strontium to calcium in their skeletons to reproduce a timeseries of ocean temperatures in the region from the year 1700 to the present day.
Dr Amos Winter is a professor of Earth and environmental systems at Indiana State University and author on the study. He told the press briefing that there is no such thing as a “perfect proxy”, but said the sclerosponge record is “as good as possible – the holy grail of reconstruction”.
He explained that the Caribbean is “the ideal location to measure global trends”. According to the paper, the region is “ideally positioned” to have a “minimal” impact from the Atlantic Meridional Overturning Circulation, while “still registering the broader effects” of the El Niño-Southern Oscillation climate phenomenon.
He adds that the sclerosponge temperature reconstruction is “very robust” when compared to other assessments of temperature trends.
Dr Gavin Schmidt, director of the NASA Goddard Institute for Space Studies, says that the new data is a “useful addition to the database” of palaeoclimate proxies. However, he adds:
“Estimates of the global mean temperatures before 1850 require multiple proxies from as wide a regional variation as possible, thus claims that records from a single record can confidently define the global mean warming since the pre-industrial are probably overreaching.”
Prof Gabi Hegerl, a professor of climate system science at the University of Edinburgh, says that the paper presents a “nice new record” of ocean temperatures, but says that “the interpretation in terms of global warming goals overstretches it”.
She warns that “a single location cannot substitute global data, as climate varies across the globe, which is why the only way to measure global temperature is to get data from across the globe”.
Similarly, Hausfather calls the finding “interesting”, but says it “should be combined with other proxy records in a larger synthesis before it will change our prevailing views here”.
The post Scientists challenge ‘flawed communication’ of study claiming 1.5C warming breach appeared first on Carbon Brief.
Scientists challenge ‘flawed communication’ of study claiming 1.5C warming breach
The UK has avoided the need for gas imports worth £5.9bn since the start of the Hormuz crisis as a result of record electricity generation from wind and solar, reveals Carbon Brief analysis.
While gas prices are surging towards levels not seen since the 2022 energy crisis, the UK has been generating record amounts of power from wind and solar, up 14% year-on-year.
This unprecedented clean-power generation is directly cutting the need for gas-fired electricity, which is down by nearly 10% year-on-year in 2026 to date.
In total, wind and solar have generated a record 41% share of the UK’s electricity needs in 2026 to date, compared with 25% from gas, according to Carbon Brief’s analysis.
The figure below shows that wind and solar generation has avoided the need for UK gas imports worth a total of £5.9bn since the outbreak of war between the US and Iran in February 2026.
The analysis shows that these avoided gas imports would have required the UK to secure the equivalent of more than 100 additional tanker deliveries of liquefied natural gas (LNG).
The £1.3bn import saving in September 2026 to date is the result of record wind and solar output, at nearly 10 terawatt hours (TWh), combined with surging gas prices.
Wholesale gas prices in the UK have remained elevated ever since Russia cut off supplies to Europe in the wake of its invasion of Ukraine in 2022. Gas averaged 90p per therm from 2023 until the start of this year, roughly three times above 2019 prices, before the Covid and Ukraine crises.
Since the outbreak of war in the Middle East in March, gas prices have climbed higher still, averaging 134p per therm or nearly four times the level seen in 2019.
In September 2026 to date, gas prices have averaged 189p per therm, reaching their highest level since the global energy crisis in 2022, as shown in the figure below.
UK gas prices are spiking again because winter is approaching – meaning higher demand for heating – and there is no end in sight for the Hormuz crisis.
At the same time, European gas stocks are low. This means Europe will have to compete with Asia to secure the cargoes of LNG needed to keep warm.
In the UK, high wholesale gas prices are hitting household gas bills under the price cap set by energy regulator Ofgem – but thanks to clean energy, electricity bills have barely increased.
From this Thursday, 1 October, typical household gas bills will be 33% higher than they were in April, some £200 per year, according to thinktank Nesta.
In contrast, household electricity bills will only have risen 4%, according to Nesta’s analysis.
Andrew Sissons, director for sustainable future at Nesta, explained in a social media post that “the link between electricity and gas prices has already begun to break”.
The UK and other fossil-fuel importing nations are being hit not only by high gas prices, but also by high prices for oil, diesel and other refined fuels. The EU has reportedly had to pay an extra €100bn for fossil-fuel imports since the start of the crisis.
For example, UK diesel prices this week hit record levels of nearly £2 per litre. In contrast, recent Carbon Brief analysis shows that electric cars are up to nine times cheaper to drive.
In her speech to the Labour party conference this week, energy secretary Miatta Fahnbulleh said that energy bills were high because the UK is “exposed to global fossil-fuel markets”.
In his own conference speech, prime minister Andy Burnham said the expansion of clean energy was easing the impact of high gas prices on electricity bills. He said:
“We are already taking more control of our electricity prices with a massive expansion of home-grown renewables and nuclear. I have asked Miatta to speed up the breaking of the link between what we pay for power at home and the international gas market, to get bills down.”
The post Analysis: Wind and solar save UK from gas imports worth £5.9bn during Hormuz crisis appeared first on Carbon Brief.
Analysis: Wind and solar save UK from gas imports worth £5.9bn during Hormuz crisis
The deadly flash flood that thundered down Nepal’s Bhote Koshi valley a month ago may have been hard to predict given the complexity of monitoring glacial slopes in the high mountains. But it should come as a surprise to no one that such a disaster could happen in a world set to barrel past the 1.5C warming limit governments agreed to in 2015.
I say this with confidence because even before the ink was dry on the Paris Agreement, former colleagues and I were writing extensively about the dangers posed by accelerating glacier melt in the Himalayas. I went back to look at what we covered, often working with local journalists in Pakistan, India and Nepal. It was substantial.
Comment: The response to Nepal’s disaster is a test for global climate institutions
In one story from a conference on climate change and geology, Bill McGuire, a professor who then led the Benfield Hazard Research Centre at University College London, was quoted as saying: “The most likely thing we are going to see soon is an increased level in giant landslides in mountainous terrains, huge collapses, millions of cubic metres of rock.”
That is precisely what unleashed Nepal’s most recent disaster, some 13 years later.
Other articles zoomed in on internationally funded programmes to prevent glacial lake outburst floods; studies warning of the rising risks to downstream communities; and cross-border efforts (or lack of them) to set up monitoring systems. But information has not led to sufficient action.
Falling behind growing impacts
Reporting on climate-related disasters over the past 20 years (it was way back then that UN aid chief John Holmes started referring to extreme weather as the “new normal”) has been a pretty frustrating beat, as things have gotten dramatically worse.
There’s no question that our understanding of the risks has grown hugely – alongside our knowledge of how to protect people and infrastructure in the face of fast-growing threats.
Yet governments and businesses have dragged their feet on adaptation policies and practical measures, even when confronted with the numbers showing it’s far cheaper to prevent and prepare than to clean up and rebuild after a flood or a storm. This intransigence has left a yawning chasm in the world’s ability to deal with climate change-driven impacts.
Let’s call it the adaptation accountability gap.
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These days we see the effects all around us – in hospital emergency rooms where workers and older people struggle with heat exhaustion; in campsites and hotels abandoned by holidaymakers fleeing forest fires; in flooded streets piled high with mud, broken furniture and twisted cars.
The only bright side to the growing climate chaos we’re experiencing is that it’s become practically impossible for politicians and corporate bosses to ignore the evidence – and the rising cost to their balance sheets. Voters who can no longer afford to shoulder the economic and social burden of this damage need to let their leaders know time’s up.
1.5C overshoot means adapting differently
Last week, during Climate Week NYC, I moderated an event packed with experts who work on adapting to climate change – from Nepal to Brazil, from Sierra Leone to the Marshall Islands, and from communities to the top of governments and UN agencies. They spoke of tree-planting to stabilise slopes, heat insurance for informal workers, a climate risk guide for midwives, drought-resistant seeds and solar panels to irrigate farmland along the Nile.
Amid the diversity of experiences and approaches, there were two common threads: first, as underlined by the UN Environment Programme’s new report on overshooting 1.5C, we may have missed the boat to catch up on adaptation as we know it.
With global warming continuing apace, we’ll need to come up with new “transformational” strategies if the coral reefs, ice sheets, oceans and other natural systems on which we rely cross tipping points and unleash cascading consequences. Nepal’s flash flood is being flagged as an example of the kind of disaster that requires a major change in how we think about adaptation.
Second, the investment required to adapt to intensifying climate shocks and stresses can no longer be seen as something to be squeezed out of shrinking foreign aid budgets. There are a growing number of tried-and-tested funds and mechanisms for channelling finance at the local, national and global levels – these must be filled, replenished and used without delay.
Businesses need to get stuck in too, not least to safeguard their assets, operations and profits – but also because in some sectors like agriculture or water there are opportunities for a return. Despite this, there are many activities governments will have no choice but to pay for, such as moving people out of the path of rising seas.
Finance not flowing where needed
Mikko Ollikainen, who heads up the UN’s pioneering Adaptation Fund for developing countries, told the event the fund has a portfolio of projects worth $1.6 billion but a pipeline waiting to be financed to the tune of $1.8 billion. Yet, in recent years, as needs balloon, donor nations have failed to meet its annual fundraising target of $300 million at COP climate summits.
The chair of the UN climate body for implementation, Julia Gardiner, said she expects to see more pressure on governments at November’s COP31 summit in Türkiye to show how they will meet a goal to triple adaptation finance by 2035 and fill the under-resourced coffers of the fledgling Fund for Responding to Loss and Damage (FRLD).
Nepal, meanwhile, is still waiting for a formal response to its request to the FRLD for urgent support to tackle the aftermath of the flood. Manjeet Dhakal, a Nepali scientist who advises least-developed countries in the UN climate process, said the disaster – which killed over 1,450 people and left nearly 6,000 missing – cannot be treated as just the latest climate crisis that grabs the headlines before it’s replaced by another.
That was backed up by Prakriti Dhakal, personal under-secretary to Nepal’s prime minister, who has been working closely on the emergency response. She said she had received many condolences and warm words of support during her meetings in New York.
But, she asked, “when you go home, will you continue having that sympathy for us that translates into something rational, something long-term, to strengthen the communities in Nepal?” A fitting response would be for governments to get behind a new Himalayan Climate Resilience Mechanism, proposed by Nepal’s leader at the UN last week, as one way to start closing the adaptation accountability gap.
The post Nepal’s disaster has laid bare the world’s adaptation accountability gap appeared first on Climate Home News.
Nepal’s disaster has laid bare the world’s adaptation accountability gap
Brazil’s environment minister says he is “very optimistic” that the Tropical Forest Forever Facility (TFFF) – a new rainforest fund to channel private and public finance to developing nations – can meet a key $10 billion funding target this year, and is not at risk from his country’s elections next month.
The TFFF, launched by Brazil at COP30 in the Amazon last November and co-led by Norway, is intended as an alternative to traditional grant-based forest finance. The fund aims to raise $125bn in public and private capital, invest it in bond markets, and then pay countries that keep their forests standing from the annual returns. Donor contributions needed to get it going have tailed off after an initial burst.
Speaking to Climate Home News on the sidelines of Climate Week in New York, Brazilian environment minister João Paulo Capobianco pointed out that in less than a year since its official launch, the TFFF has already secured $7.3bn from governments.
“How many other initiatives can say that?” he asked. “Of course, if you have $7 billion, it’s easier for more countries to consider their own contribution. And not just countries – non-governmental organisations also. We are expecting even more support.”
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As its initial target, the TFFF aims to raise $10bn in seed capital from governments by the end of 2026, and still needs to fill a gap of $2.7bn. Its backers say that for each dollar in public funding, they can secure $4 from the private sector. Critics say the $10bn goal barely covers the fund’s expenses and would not allow it to make any significant payments to forest countries.
Because setting up its financial architecture, raising the starting capital and making the first investments will take time, experts say the TFFF is unlikely to generate any payments for developing countries before 2028.
Seeking new pledges
Capobianco told Climate Home News that Brazil is still in talks with potential new contributors to the fund, among them China, Korea and Japan, and said he hoped to see more pledges announced at the upcoming biodiversity and climate COPs in October and November. The Netherlands is expected to up its first small contribution and Canada may also come in, according to other sources close to the TFFF.
Because the fund was not created as part of the UN climate talks and is hosted by the World Bank, developing countries can contribute without taking on wider donor responsibilities for climate finance. Brazil and Indonesia – both large emerging rainforest nations – have each pledged $1bn to the TFFF.
Earlier in September, the UK became the latest country to pledge funding – promising a loan of £400 million (about $540 million). Capobianco welcomed the contribution and noted that Britain has also said it will keep “under review” the possibility of putting in more.
Currently the largest donor is Norway, which announced a $3bn pledge last year at COP30 in Belém. However, that pledge came with conditions, among them that the fund must reach $10bn in sponsor capital by 2026, and that Norway’s contribution can’t make up more than 20% of that total. Over the longer term, this means the fund must raise $15bn from governments to unlock Norway’s full investment.
Comment: UK’s budget juggling trick with rainforest loan for bus-fare cap needs transparency
Speaking at a forest finance event in New York, Norway’s environment minister Sigrun Aasland said the country’s pledge was made not “only out of solidarity but because of shared interests”, adding that protecting rainforests is critical for climate and biodiversity goals as well as for national security.
“Tropical deforestation matters to people in the Amazon and in the Congo. But let’s not forget that it also matters to global food production and to the cost of living in Oslo or in London,” she said.
At the event, Guyana’s minister of natural resources Vickram Bharrat said the TFFF is “one in a menu of options” to finance forest protection in developing countries. He added that to boost its capital “maybe we should put some amount of pressure on oil companies to contribute to the fund”.
Upcoming election “not a risk”
Brazil, which has been pivotal to getting the fund off the ground, is now heading into a national election that could see the country swing back to an anti-climate stance if right-wing candidate Flávio Bolsonaro beats current left-wing President Luiz Inacio Lula da Silva. Capobianco, however, said the election result does not pose a risk to the TFFF.
“It’s a global initiative, not a Brazilian initiative. We proposed the first idea, but nowadays it’s a global initiative,” he said. “We believe the investor countries and the tropical countries together have the possibility to continue this process.”
In Brazil, the first round of voting is scheduled for Sunday, October 4. If no candidate wins more than 50% of valid votes, a run-off ballot will take place on October 25.
COP30 roadmap to end deforestation will invite countries to draft domestic plans
In July, the TFFF board adopted a charter, which outlines the instrument’s objectives and values, including that 20% of the payments made to tropical countries will go directly to Indigenous people and local communities.
The charter also says the TFFF board may comprise up to 12 member countries during the initial phase. Currently, seven seats are filled by the Democratic Republic of Congo (DRC), Germany, Brazil, France, the Netherlands, Norway and Indonesia.
The board has also formally incorporated the Tropical Forest Investment Fund (TFIF) – the TFFF’s investment arm that will trade bonds in financial markets – hosted in Luxembourg.
The post Brazil confident new rainforest fund will reach $10bn donor milestone appeared first on Climate Home News.
Brazil confident new rainforest fund will reach $10bn donor milestone
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