Cutting emissions in line with the 1.5C warming limit, rather than following current climate policies, could curb long-term sea level rise by 64cm, a new study says.

The research, published in Nature Climate Change, projects how much sea level rise will be unavoidable – or “locked in” – by the year 2300, due to emissions over the coming decades.

According to the authors, 29cm of global average sea level rise is already in the pipeline due to the emissions that were released up to the year 2020.

Following current climate policies until the year 2090 will “lock in” an additional 79cm of sea level rise for the year 2300, the study finds.

However, reducing emissions in line with 1.5C would cut this additional sea level rise to 15cm.

The analysis shows that “if we reduce emissions rapidly in the coming decades, there is a clear path to limiting the legacy of sea level rise”, the lead author of the study tells Carbon Brief.

The study also explores regional sea level rise, showing that Pacific small-island nations will face some of the highest rates of sea level rise.

A scientist not involved in the research tells Carbon Brief that the paper “exposes a deep inequity” between nations, arguing that this makes “ambitious” action to cut greenhouse gas emissions “not just a climate necessity, but a climate-justice imperative”.

‘Locked in’

Average global sea level has risen by more than 20cm since 1900, driven mainly by human-caused climate change through thermal expansion of the ocean and the melting of glaciers and ice sheets.

Rising seas are already threatening to wipe out small-island nations, jeopardising the security, livelihoods and cultures of people who live in these areas. Meanwhile, coastal regions around the world are facing more frequent flooding, erosion and saltwater intrusion.

The authors of the new study explain that emissions released over the coming decades will affect global sea levels for hundreds of years. This is because the oceans and ice sheets respond slowly to past and present warming, they note.

The authors call this “locked in” or “committed” sea level rise.

The study explains that sea level projections are generally based on 21st century emissions pathways, but notes that “late-century emissions then dominate the longer-term sea-level response and mask the impact of near-term emissions”.

In contrast, this study assesses the impact of emissions both early and late in the 21st century – including past emissions and those projected to occur under different emissions pathways. The research investigates how much sea level rise will be locked in by the year 2300 through these emissions.

According to the authors, 29cm of global average sea level rise, compared to 1995-2014, is already locked in due to the emissions that were released up to the year 2020.

Rising seas

The study uses emulators – simple climate models with lower time and computational costs than full-scale Earth system models – to model how much sea level rise will be locked in by 2300 due to 21st century emissions.

The authors chose five emissions pathways and ran multiple model runs where they simulated sudden stops in emissions at the end of each decade for each pathway. This allowed them to isolate the emissions just until these dates.

For example, modelling a sudden drop in emissions in the year 2050 allows the authors to calculate how much sea level rise over the next two centuries is driven solely by human-caused emissions released over the next two decades.

The authors use five emissions pathways:

• SSP1-1.9: A very-low emissions reductions pathway “consistent with” the Paris Agreement’s 1.5C limit
• SSP1-2.6: A “low” emissions pathway consistent with 2C of warming
• SSP2-4.5: A “current climate policy-like trajectory”
• SSP3-7.0: A “high” emissions pathway
• SSP5-8.5: A “very-high emissions” pathway

The left-most panel shows how much additional sea level rise is locked in for the year 2300 due to emissions produced between 2020 and 2030. The next three panels show the results for emissions produced between 2020 and 2050, 2070 and 2090, respectively.

The plot shows that higher levels of greenhouse gas emissions lock in more sea level rise for the year 2300.

The authors find that, under the SSP2-4.5 “current climate policies” scenario, human-produced greenhouse gas emissions over 2020-50 will lock in an additional 29cm of sea level rise by the year 2300. This number grows to 79cm when including emissions out to 2090 under this scenario.

Meanwhile, under the scenario consistent with the 1.5C limit, only 15cm of additional sea level rise will be locked in by 2090.

This means that efforts to cut greenhouse gas emissions over the coming decades could curb long-term sea level rise by an extra 64cm.

The study authors say that their results “reinforce how every increment of additional peak warming from cumulative emissions irreversibly increases sea level rise”.

Dr Alexander Nauels is a science adviser at Climate Analytics and lead author on the study. He tells Carbon Brief that the world is “already committed to a really substantive amount of sea level rise” and stresses that this must be considered in terms of “adaptation, planning and risk management”.

However, he adds, “if we reduce emissions rapidly in the coming decades, there is a clear path to limiting the legacy of sea level rise that we would produce in the coming decades”.

Dr Catia Domingues, is a researcher at the UK’s National Oceanography Centre and was not involved in the study. She tells Carbon Brief that the study’s methodology is “clever and necessary”. She adds:

“[The study] clearly shows how the emissions from just the next 30 years, under current climate policies, will write an irreversible chapter for centuries to come, locking in significant sea level rise on their own.”

Warming levels

The authors also calculate the committed sea level rise at different warming levels.

The chart below plots sea level rise against warming level for every scenario and time period used in the study. It highlights how higher levels of warming commit the world to ever higher seas.

Committed sea level rise by 2300 at different warming levels, under SSP1-1.9 (light blue), SSP1-2.6 (dark blue), SSP2-4.5 (yellow), SSP3-7.0 (red) and SSP5-8.5 (dark red) pathways. Circles, X’s, squares and crosses indicate data points for 2030, 2050, 2070 and 2090 respectively. The green and blue lines show the 1.5C and 2C temperature thresholds. Source: Nauels et al (2025).

The authors note that the relationship between global temperature and committed sea level rise to 2300 is not “linear”, noting that the amount of sea level rise that is locked in by warming accelerates as global temperatures rise.

The authors explain that this is due to a “non-linear increase in ice mass loss in a warmer world” – in other words, physical feedbacks mean that higher levels of warming could see disproportionately large increases in ice losses.

Nauels tells Carbon Brief many sea level processes, such as ice-sheet responses, are still not “fully understood”. This means that when looking out to 2300, there can be “large uncertainties” in results, he adds.

Nevertheless, he argues that it is “still very important to explore the longer-term sea level response, because of the huge risk that is attached to it”.

Inequity

The main findings of the study focus on global average sea level rise. However, the authors note that sea level rise is not consistent across the world, with some regions facing faster rates of sea level rise than others.

This is largely due to ocean currents, driven by wind, warming, evaporation and rainfall, which push large masses of water around the planet. It is also caused by the bumpy, non-uniform surface of the earth.

To show these differences, the authors also selected a handful of coastal regions to study.

Nauels tells Carbon Brief that the study authors decided to focus on a handful of regions that “diverge” from the average global trend.

For example, they find that Pago Pago – the capital of American Samoa, which is made up of a string of coastal villages – will experience greater committed sea level rise than the global average.

On the other hand, Oslo is experiencing “land uplift” and actually shows a drop in sea level under the lowest warming scenario.

The NOC’s Domingues tells Carbon Brief that the study “exposes a deep inequity” between nations. She adds:

“This makes ambitious mitigation not just a climate necessity, but a climate-justice imperative.”

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The post Rapid emissions cuts would avoid 64cm of ‘locked in’ sea level rise by 2300 appeared first on Carbon Brief.

Rapid emissions cuts would avoid 64cm of ‘locked in’ sea level rise by 2300

We handpick and explain the most important stories at the intersection of climate, land, food and nature over the past fortnight.

This is an online version of Carbon Brief’s fortnightly Cropped email newsletter. Subscribe for free here.

Key developments

Deforestation dropping, but not fast enough

LOSING FOREST: The world lost almost 11m hectares of forest each year over the past decade – an area almost the same size as Iceland, the UN Global Forest Resources Assessment found. The overall rate of deforestation slowed over 2015-25 – compared to annual losses of 13.6m hectares over 2000-15 and 17.6m hectares over 1990-2000. [Carbon Brief will publish an article later this week detailing more key findings.] Elsewhere, a different UN report found that annual spending on forests must more than triple to $300bn by 2030 to meet climate and nature goals.

POOR PROGRESS: At the same time, a third report found that more than 8m hectares of forest was destroyed in 2024 – which is 63% above the trajectory needed to put an end to deforestation by 2030. The Forest Declaration Assessment report said that countries are off track to meet a pledge from more than 100 countries to halt and reverse global deforestation by 2030. It noted that agriculture caused 86% of global deforestation in the past decade. In its coverage of the report, Climate Home News noted that experts said the findings were a “wake-up call” ahead of COP30 in the Amazon.

FOREST FINANCE: An investigation from Global Witness found that banks and asset managers around the world generated $26bn from “financing deforesting companies” through investments, loans and other financial services between 2016 and 2024. US financial institutions earned the biggest gains, it said. Elsewhere, the EU “u-turn[ed]” on plans to delay its anti-deforestation law until 2026, instead suggesting tweaks to allow more time for compliance, according to Politico. Separately, an NGO report found that timber imports from companies operating in the EU “can be traced to logging on Indonesia’s Borneo island”, Agence France-Presse said.

Nature congress 

EXTINCTION RISK: A new global assessment published by the International Union for Conservation of Nature (IUCN) found that more than 60% of the world’s bird species are in decline, the Guardian reported. In 2016, the equivalent figure was 44%. The outlet underscored that deforestation, largely bolstered by the expansion of agriculture and human development, is the main cause of falling populations. The Washington Post added that Arctic mammals, such as seals, whales and polar bears, are also “increasingly threatened by extinction” due to pressures from climate change.

SIGNIFICANT IMPROVEMENT: The IUCN report also showed some “bright spot[s]”, as is the case with green sea turtles, which “have recovered substantially thanks to decades of conservation efforts”, explained the Washington Post. A scientist leading the sea turtle assessment told the New York Times that the rebound “comes down to reducing threats”. As another example of species recovery, the outlet pointed to the island of Rodrigues in the Indian Ocean, where two bird species on the brink of extinction are now listed as species of least concern, thanks to restoration work carried out by conservationists.

BIODIVERSITY CONGRESS: The report was published against the backdrop of this year’s IUCN congress on biodiversity conservation, which saw members adopt a 20-year strategic vision that boosts human rights and social justice alongside conservation, according to the IUCN. EFE Verde reported on the congress, where there was a call to action for countries to speed up the implementation of the Kunming-Montreal Global Biodiversity Framework and to ensure that 30% of the planet is protected by 2030. However, new analysis from Carbon Brief showed that just 28% of countries have submitted their plans for biodiversity conservation to the UN a year after the deadline.

News and views

WILDFIRE WATCH: The annual “state of wildfires” report found that extreme wildfires released more than 8bn tonnes of CO2 during the March 2024-February 2025 global fire season. The report, published by an international team of scientists and covered by Carbon Brief, showed that wildfires covered at least 3.7m square kilometres – an area larger than India – and exposed more than 100 million people around the world to these extremes.

BIOFUEL BOOST: At COP30, Brazil is expected to ask countries to quadruple their use of “sustainable fuels” over the next decade, including biofuels, biogas and hydrogen, as reported by the Guardian. A leaked document seen by the outlet revealed that Brazil argues biofuels will displace fossil fuels. However, biofuels – which are fuels derived from organic matter – are considered controversial by environmental experts, due to their potential to increase deforestation and promote monocultures, the outlet added. Separately, a new Carbon Brief Q&A explored how countries are using biofuels to meet their climate targets.

AGRIBUSINESS MOVE: Brazil’s agribusiness – the largest emitting-sector in the country and a major driver of deforestation – plans to present the country as a leader in sustainable agriculture at the upcoming COP30, Bloomberg reported. The farm lobby faces international pressure from policies such as the EU law that requires Brazil to ensure that its crop exports are free from deforestation, the outlet said.

LONG LIVE THE WHALES: A “historic lawsuit” to protect whales in the Gulf of California has been accepted for a hearing by two district courts in Mexico, Animal Político reported. The suit aims to declare the area a “critical habitat” and rule that previously granted permits for shipping liquefied natural gas through the gulf are unconstitutional. El País also covered the news and added that a coalition of civil-society organisations is advocating for the recognition of whales as “subjects of rights”.

LARGE EMISSIONS: In 2023, 45 major meat and dairy companies emitted more than 1bn tonnes of greenhouse gases, comparable to the emissions of top fossil-fuel producers, according to a new report by civil society organisations. The report found that the top five highest-emitting firms – JBS, Marfrig, Tyson, Minerva and Cargill – were responsible for 480m tonnes of CO2-equivalent emissions. The 45 firms’ methane emissions exceeded those from the EU and UK, it added. Elsewhere, Nestle withdrew from a global alliance of dairy producers for reducing methane emissions, without providing a reason, Reuters reported.

PRICE HIKE: Over the past year, extreme weather has driven up prices by 16% for five products – butter, beef, milk, coffee and chocolate – together responsible for 40% of food inflation over that time, according to research covered by the Daily Mail. The outlet said that “alternating periods of drought, extreme heat and heavy rainfall are affecting farmers” globally. The Financial Times also covered the report, writing that its “findings challenge the narrative promoted by industry groups that have linked high grocery bills to domestic policies”.

Spotlight

Researching climate impacts on Thai tree seeds

This week, Carbon Brief details how Kew Gardens researchers are studying the effects of extreme heat and drought on trees in Thailand.

Forests in Thailand, as in many other parts of the world, are feeling the effects of climate change – from the country’s mountain peaks in the north to its mangroves on the southern coast.

Scientists at Kew Gardens are assessing how certain tree species react to high temperatures and drought to help inform efforts in re-planting degraded forests across the country.

The is one of several projects from Kew’s Millennium Seed Bank, which this week marks its 25th anniversary. It is the world’s largest collection of wild plant seeds, holding almost 2.5bn seeds from 40,000 different species.

Incubating seeds

For the Thailand project, researchers collected 60,000 seeds from three tree species growing across the country. They focused on tree types which benefit local people, such as the Sapindus rarak, whose seed can be used as a washing detergent.

The scientists sought seeds from areas with “different climates and altitudes” – ranging from the country’s highest mountain, Doi Inthanon, to its lowlands – to try to find out which areas yield resilient seeds, Dr Jan Sala, a researcher at the seed bank, told Carbon Brief.

The Kew team is collaborating on the project with the Forest Reforestation Research Unit (Forru), a research team at Chiang Mai University in Thailand that restores degraded forests.

The researchers are still analysing their data and hope to publish the findings next year, but Sala said initial observations show some “interesting” differences in how the thousands of tree seeds respond to warming and drought. He told Carbon Brief:

“We cannot say this for sure because we have not finished the analysis, but hopefully we identify a couple of populations…that are resilient to climate change.”

To study this, they put each of the thousands of seeds into incubators and subjected them to temperatures ranging from 5C to 50C across different periods of time. They wanted to see how the seeds germinate under various conditions and identify “whether a population or species reacts differently to temperature rising”, Sala says.

Building resilient forests

Dr Inna Birchenko, a research associate at the Millennium Seed Bank who was also involved in the project, told Carbon Brief that the Thailand study findings can help to ensure that restored forest plots have the “best chance for long-term survival”.

She noted that resilient forests “contribute to decarbonisation by locking carbon in the trunks, as opposed to just being a wasteland or being an agricultural land”.

Sala said the researchers hope to not only help Forru decide which seeds to use in different restoration projects, but also provide more information to “all practitioners across Thailand”.

Birchenko noted that while temperate trees are generally well-researched, tropical species are “so understudied”. She told Carbon Brief:

“Every day, I’m trying to find extra information about the genetics of this or that species, and there is absolutely nothing…So we are hoping that this potentially snowballs into more effort into this area.”

Watch, read, listen

FLYING HIGH: A Guardian article visualised how bird migration around the world is being reshaped by “new threats”, including climate change.

ON THE MOVE: Yale Environment 360 explored how US border-wall construction is “creating a roadblock” to the return of jaguars in the country’s south-west as Mexico’s populations recover.

OVERFISHING ISSUES: An article in Vox looked at how nature conservation projects in Madagascar could be reshaped to prevent them “mak[ing] it harder for desperately poor people to make a living”.
VALUABLE VOCABULARY: An Atmos video addressed a study on how the English language is losing nature-related words, undermining people’s connection to nature.

New science

• China’s demand for Brazilian soya beans – used as animal feed – is driving agricultural expansion and deforestation in Brazil, with nearly 18m hectares of land in the South American country used to grow soya for export to China | Nature Food
• A review of climate adaptation practices among vegetable farmers in Africa found that most solutions focused on addressing drought, flooding and rainfall, primarily through technological solutions | Communications Earth and Environment
• Aboveground vegetation in Australian humid tropical forests has become a carbon source due to extreme temperatures and other climate anomalies, leading to higher rates of tree mortality and losses in biomass | Nature

In the diary

• 20-30 October: UN Convention on Biological Diversity subsidiary body meetings | Panama City
• 22-25 October: 43rd session of the European Forestry Commission | Istanbul, Turkey 
• 26 October:Argentina legislative election

Cropped is researched and written by Dr Giuliana Viglione, Aruna Chandrasekhar, Daisy Dunne, Orla Dwyer and Yanine Quiroz. Please send tips and feedback to cropped@carbonbrief.org

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Cropped 10 September 2025: Flooded ‘food baskets’; Brazil eyes forest finance; Resilient rice

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The post Cropped 22 October 2025: Global forest loss dips; Bird species in peril; Climate impact on Thai trees appeared first on Carbon Brief.

Cropped 22 October 2025: Global forest loss dips; Bird species in peril; Climate impact on Thai trees

Just 28% of countries have met a UN call to submit new plans on addressing nature loss – a year after the original deadline, Carbon Brief analysis shows.

Several of the world’s most biodiverse countries – including Brazil, the Democratic Republic of the Congo and South Africa – are among those that have not yet released their nature plans.

Countries were asked to submit their pledges, known as national biodiversity strategies and action plans (NBSAPs), by the start of the COP16 biodiversity summit in Colombia on 21 October 2024.

After only 15% of nations met the original deadline, countries agreed at the summit to a new text that “urges” countries to release their NBSAPs “as soon as possible”.

Many developing countries have expressed that a lack of available funding has prevented them from publishing their NBSAPs.

A spokesperson for the Global Environment Facility (Gef), the multilateral fund that provides funding to help with the preparation of NBSAPs, tells Carbon Brief that 120 out of 139 countries that have requested financial support since COP16 have been able to access it.

The spokesperson adds that the UN Environment Programme is “working to resolve outstanding issues” to allow the remaining 19 countries to access financial assistance.

Lack of action

In 2022, nations signed a landmark agreement called the Kunming-Montreal Global Biodiversity Framework (GBF), which aims to halt and reverse nature loss by 2030. It is often described as the “Paris Agreement for nature”.

As part of the agreement, countries agreed to submit new NBSAPs “by” COP16, which began on 21 October 2024 in Cali, Colombia. (Countries failed to find agreement on some key issues in Colombia and met again in Rome, Italy, in February 2025 for a resumed session of COP16.)

NBSAPs are blueprints for how individual countries plan to tackle biodiversity loss and ensure they meet the targets outlined in the GBF.

They are similar to nationally determined contributions (NDCs), the plans that outline how individual countries envisage meeting the goals of the Paris Agreement. However, a key difference is that countries are legally obliged to submit NDCs, but not NBSAPs.

The publishing of new NBSAPs was meant to ensure that countries actually implement the targets of the GBF within their borders.

A lack of implementation was widely cited as one of the major factors behind the failure of the last set of global biodiversity rules, the Aichi targets, which were agreed in 2010.

A joint investigation by Carbon Brief and the Guardian found that 85% of countries missed the UN deadline to submit their NBSAPs by COP16.

At COP16, many countries lamented the lack of NBSAP submissions. At the summit, they agreed to a new text that notes the lack of action and “urges” countries to release their NBSAPs “as soon as possible”.

Now, new Carbon Brief analysis reveals that just 28% of nations (55 of 196 parties) have released their NBSAPs – a year after the deadline.

The map below shows countries that submitted their plans to the UN by the 21 October 2024 deadline (light green) and after the deadline (dark green).

Since the original deadline, both Germany and the UK have submitted their NBSAPs. This means that the US, which is not a signatory to the UN Convention on Biological Diversity, is now the only G7 nation without a nature plan.

Eight of the “megadiverse countries” – 17 nations that together provide a home to 70% of the world’s biodiversity – are yet to produce their NBSAPs.

This includes Brazil, the world’s most biodiverse nation and host of the upcoming COP30 climate summit.

The other megadiverse countries that have not yet submitted their NBSAPs are the DRC, Ecuador, Madagascar, Papua New Guinea, the Philippines, South Africa and the US.

The host of next year’s COP17 biodiversity summit, Armenia, is also among those yet to produce an NBSAP.

According to the GBF and its underlying documents, countries that were “not in a position” to meet the deadline to submit NBSAPs ahead of COP16 were requested to instead submit national targets.

These submissions simply list biodiversity targets that countries will aim for, without an accompanying plan for how they will be achieved.

By the end of the COP16, some 119 parties had produced at least one national target. A year later, this figure has risen to 141, or 72% of countries.

Finance flows

At COP16 in 2024, many developing nations said that a lack of timely funding available from the Gef had prevented them from being able to produce new NBSAPs.

In acknowledgement of this, the NBSAPs text agreed at the summit “requests” the Gef to “provide timely support to all eligible parties, aligned with national circumstances and needs, upon request, to enable them” to release their plans.

A spokesperson for the Gef tells Carbon Brief that 120 out of 139 countries that requested financial support have been able to access it, saying:

“Since 2022, the Gef has approved $123.2m in two tranches to support 139 eligible countries through implementing agencies with their NBSAPs updates or revisions. The 138 countries that requested it had access to a first tranche of support of $44.7m.

“Since October 2024, the second tranche of support has been disbursed by UNDP and UNEP to 120 out of the 139 countries that requested it. UNEP is working to resolve outstanding issues and expedite pending disbursements of the second tranche of support for the remaining 19 countries.”

Panama to Yerevan

Country representatives are currently gathered in Panama City, Panama, for preparatory talks for the next UN biodiversity summit, COP17, which will take place in Yerevan, Armenia, over 19-30 October in 2026.

At COP17, the first global review of nations’ progress to achieving the goals of the GBF is set to take place.

This review will draw from the available NBSAPs, as well as national targets and separate national reports, which are due to be submitted by February 2026.

There is little evidence to suggest that the world is on track to meet the GBF’s mission to halt and reverse biodiversity loss in just five years.

For example, an investigation by Carbon Brief and the Guardian published this year revealed that more than half of nations that have submitted NBSAPs do not commit to the GBF’s flagship target of protecting 30% of land and seas for nature by 2030.

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The post Analysis: Just 28% of countries have released nature pledges a year after UN deadline appeared first on Carbon Brief.

Analysis: Just 28% of countries have released nature pledges a year after UN deadline