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Even passing 1.5C of global warming temporarily would trigger a “significant” risk of Amazon forest “dieback”, says a new study.

Dieback would see large numbers of trees die, shifting the lush rainforest into a dry savannah.

The research, published in Nature Climate Change, assesses the impact of “overshooting” the aspirational goal of the Paris Agreement on the Amazon and Siberian forests.

Overshoot would see warming surpass 1.5C above pre-industrial levels in the coming decades, before being brought back down before 2100 through large-scale carbon dioxide removal.

Using hundreds of climate-model simulations, the authors assess the influence of the “sensitivity” of the climate – a measure of the planet’s temperature response to a given increase in atmospheric CO2.

Across all simulations where global warming in 2100 surpasses 1.5C, 37% show “some amount of dieback”, the study says.

However, the risk increases further in the long term, with “55% of simulations exhibiting dieback by 2300”.

One author tells Carbon Brief that the study highlights that overshooting 1.5C leaves forest ecosystems “exposed to more risk than [they] need to be”.

The findings show that “we can’t afford complacency”, he warns.

Warming pathways

As the planet warms, there is an increasing risk that parts of the Earth system will cross “tipping points” – critical thresholds that, if exceeded, could push a system into an entirely new state.

For example, a seminal 2022 study warned that five tipping elements – including the collapse of the West Antarctic ice sheet and abrupt permafrost thaw – are already within reach, while others are becoming increasingly more likely as temperatures rise.

One way to limit warming to 1.5C by the end of the century involves initially overshooting the threshold. However, research published last year warns that the longer the 1.5C threshold is breached – and the higher the peak temperature – the greater the risk of crossing tipping points.

The new study uses modelling to investigate the risks of overshoot for the Amazon and Siberian forests.

The paper considers three illustrative mitigation pathways taken from the Intergovernmental Panel on Climate Change’s (IPCC) mitigation report from its sixth assessment cycle, which was published in 2022.

Gregory Munday is an applied scientist at the UK Met Office Hadley Centre and lead author on the study. He tells Carbon brief that the authors selected “optimistic” pathways that “each have different relationships to the Paris Agreement goals”.

For each scenario, the authors assess a range of different climate sensitivities – a measure of the planet’s temperature response to a given increase in atmospheric CO2. The average outcome of each pathway is:

  • The “renewables” scenario shows a future with reduced emissions and a heavy reliance on renewable energy, which keeps warming below 1.5C by 2100.
  • The “negative emissions” pathway shows a world in which warming initially overshoots the 1.5C threshold, but extensive use of carbon removal sees warming drop back below 1.5C before 2100.
  • The “gradual strengthening” pathway illustrates a strengthening of climate policies implemented in 2020, with rapid reductions mid-century and a reliance on net-negative emissions by the end of this century. This pathway sees global average temperatures reach 1.8C by 2100. 

The authors run the emissions pathways through a simple climate “emulatormodel, which calculates the global temperatures associated with each emission pathway.

The charts below show cumulative CO2 emissions (left), atmospheric CO2 concentration (middle) and changes in global average surface temperature compared to the pre-industrial level (right), for the renewables (green), negative emissions (purple) and gradual strengthening (yellow) pathways until the year 2300.

The panels show cumulative CO2 emissions (left), atmospheric CO2 concentration (middle) and changes in global average surface temperature compared to the pre-industrial level (right), for the C1:IMP-Ren renewables scenario (green), C2:IMP-Neg negative emissions (purple) and C3:IMP-GS gradual strengthening (yellow) pathways until the year 2300. Source: Munday et al. (2025)
The panels show cumulative CO2 emissions (left), atmospheric CO2 concentration (middle) and changes in global average surface temperature compared to the pre-industrial level (right), for the C1:IMP-Ren renewables scenario (green), C2:IMP-Neg negative emissions (purple) and C3:IMP-GS gradual strengthening (yellow) pathways until the year 2300. Source: Munday et al. (2025)

The authors then use a different modelling framework to project the impacts of each emissions scenario.

Study author Dr Chris Jones leads the UK Met Office Hadley Centre’s research into vegetation and carbon cycle modelling and their interactions with climate. He tells Carbon Brief that the new study is the first application of this modelling framework, which he describes as a “rapid response tool”.

He says the tool was developed to “rapidly look at a range of climate outcomes, both global and local, for new scenarios”, adding that it provides a “pretty good approximation” of what traditional global climate models would do.

Munday adds that the framework is able to produce results within days or weeks, rather than taking “months and months”.

Finally, the authors use land surface model JULES to assess forest health under the different scenarios. Overall, the authors produce 918 simulations each of Amazon and Siberian forest health.

Forest health

The authors assess forest health using two metrics. The first is the forest growth metric “net primary productivity”, a measure of the rate that energy is stored as biomass by plants, which can indicate forest productivity. The second metric, forest cover, is a way of measuring the forest’s long-term response.

The models show that rising CO2 levels causes net primary productivity to increase, due to the CO2 fertilisation effect, driving more rapid forest growth. Conversely, many of the impacts of climate change, such as increased heat and changes to rainfall patterns, can be detrimental to forests, damaging or killing trees.

To identify the impacts of overshooting 1.5C on the Amazon and Siberian forests, the authors compare the “renewables” and “negative emissions” pathways. Both of these scenarios reach a similar global average temperature by the year 2100, but the former does so without overshoot, while the latter overshoots 1.5C before temperatures come back down.

The maps below show the difference in net primary productivity in the Amazon (left) and Siberian forests (right) between the two scenarios in the year 2100. Brown shading indicates that net primary productivity was higher in the non-overshoot scenario, while blue indicates that it was higher in the overshoot scenario.

The difference in net primary productivity in the Amazon (left) and Siberian forests (right) between the two scenarios. Brown indicates that net primary productivity was higher in the renewables (non-overshoot) scenario, while blue indicates that it was higher in the negative emissions (overshoot) scenario. Source: Munday et al. (2025)
The difference in net primary productivity in the Amazon (left) and Siberian forests (right) between the two scenarios. Brown indicates that net primary productivity was higher in the renewables (non-overshoot) scenario, while blue indicates that it was higher in the negative emissions (overshoot) scenario. Source: Munday et al. (2025)

The maps show that “large areas of both Amazonian and Siberian forest show reduced net primary productivity” by 2100 due to overshoot, compared to a scenario with no overshoot, the paper says.

‘High-risk zones’

From the three pathways, the authors generate 918 simulations of future climate and corresponding Amazon forest health.

The authors use these results to identify which future temperature and rainfall conditions result in net forest “dieback”. This is when large numbers of trees die, shifting the rainforest into a dry savannah.

The plots below show which simulations result in Amazon dieback by the year 2100 (left) and 2300 (right), for different amounts of rainfall and temperature levels in the year 2100. Each graph is divided into four sections – hot and wet (top right), hot and dry (bottom right), cold and wet (top right) and cold and dry (bottom right). These sections are based on average regional temperature and rainfall in the year 2100.

Coloured dots indicate scenarios that see forest dieback. These are coloured by pathway, for renewables (green), negative emissions (purple) and gradual strengthening (yellow). Grey dots indicate scenarios without Amazon dieback. The red lines indicate “high-risk climatic zones”, above which there is “a significant risk of dieback”.

Amazon dieback in the year 2100 (left) and 2300 (right), for different amounts of rainfall and temperature levels in the year 2100. Coloured dots indicate scenarios that see forest dieback. These are coloured by pathway, for renewables (green), negative emissions (purple) and gradual strengthening (yellow). Grey dots indicate scenarios without Amazon dieback. Source: Munday et al. (2025)
Amazon dieback in the year 2100 (left) and 2300 (right), for different amounts of rainfall and temperature levels in the year 2100. Coloured dots indicate scenarios that see forest dieback. These are coloured by pathway, for renewables (green), negative emissions (purple) and gradual strengthening (yellow). Grey dots indicate scenarios without Amazon dieback. Source: Munday et al. (2025)

The study finds that most Amazon dieback scenarios happen in hot, dry conditions, the authors note.

Across all simulations where warming in 2100 is above 1.5C, 37% show “some amount of dieback” the study says. However, in these model runs, the risk increases further in the long term, the study notes, with “55% of simulations exhibiting dieback by 2300”.

Prof Nico Wunderling is a professor of computational Earth system science at the Potsdam Institute for Climate Impact Research and was not involved in the new research. He tells Carbon Brief it is significant that, according to this study, the Amazon will face impacts from climate change below the tipping point threshold of 2-6C, as assessed in the landmark 2022 tipping points paper.

The authors also carry out this analysis for Siberian forests. Instead of a drop in tree cover, they find a change in the composition of trees. Munday tells Carbon Brief that the vegetation shifts “from grassy surface types to lots more trees and shrubs” in a process called “woody encroachment”.

Woody encroachment can have significant negative impacts on terrestrial carbon sequestration, the hydrological cycle and local biodiversity.

“The Siberian forest is probably committed to a long-term, and possibly substantial, expansion of tree cover,” the authors write.

High-risk scenarios

The greatest uncertainty in this study comes from the spread of climate sensitivities, Munday tells Carbon Brief.

He elaborates:

“This means that although we simulate the impacts from extremely optimistic mitigation scenarios, there is a chance that the Earth’s climate sensitivity is much higher than we expect, and so, small but significant risks of short- and long-term forest ecosystem impacts exist in spite of the choice of these strong-mitigation scenarios.”

In other words, if climate sensitivity is higher than expected, forests could face harmful impacts even under low emissions scenarios.

Dr David McKay – a lecturer in geography, climate change and society at the University of Sussex – is the lead author of the 2022 study. He tells Carbon Brief that the new paper “shows the value in focusing not just on model averages, but also exploring a wide range of possible futures to capture potential ‘low probability, high impact’ outcomes”. He adds:

“[The study shows] how negative emissions to reduce warming might help restabilise these forests in future if we do overshoot 1.5C, but as such large-scale CO2 removal remains hypothetical, we shouldn’t assume we can rely on this in practice.”

However, McKay also notes some uncertainties in the models used. Mckay tells Carbon Brief that the vegetation model used in this study doesn’t include fire and “has some limitations around soil moisture stress and vegetation in the tundra”. These are “likely important for resolving potential tipping points in these biomes”.

Therefore, he adds, the study “doesn’t show how regional tipping points could potentially further amplify and lock-in these future forest shifts, even with negative emissions”.

Dr David Lapola is researcher at the University of Campinas in Brazil and was not involved in the study. He also warns that vegetation models provide a “poor representation of how CO2 may affect these forests directly”. Lapola argues that scientists must “collect field data to make any new advancement with models”.

Nevertheless, Lapola tells Carbon Brief that studies such as this will be “extremely useful” for the IPCC’s upcoming seventh assessment cycle, which will include a dedicated chapter on tipping points and other “low-likelihood high impact events” for the first time.

Study author Jones tells Carbon Brief that overshooting 1.5C leaves forest ecosystems “exposed to more risk than [they] need to be”. The findings show that “we can’t afford complacency”, he warns.

The post ‘Significant’ risk of Amazon forest dieback if global warming overshoots 1.5C appeared first on Carbon Brief.

‘Significant’ risk of Amazon forest dieback if global warming overshoots 1.5C

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Scientists Deploy First Satellite Tag on a Leatherback Sea Turtle in Ecuador to Better Reveal Gaps in Ocean Protection

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Tracking the turtle’s movements could help identify where high-risk fishing areas overlap with the critically endangered species.

Just after 3 a.m. on a recent Friday morning, a 4.5-foot-long leatherback sea turtle covered her freshly dug nest with sand, sweeping and packing it into place with steady strokes of her flippers just above the high tide along a remote, rugged stretch of Ecuador’s Pacific coast.

Scientists Deploy First Satellite Tag on a Leatherback Sea Turtle in Ecuador to Better Reveal Gaps in Ocean Protection

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Green Climate Fund picks locations for five developing country hubs

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The UN’s flagship climate fund has selected five locations for its new regional offices, a move aimed at bringing it physically closer to developing countries and making its finance easier to access.

After fraught discussions during a meeting last week, the board of the Green Climate Fund (GCF) decided in a secret vote on Saturday to open regional offices in Panama City, Amman in Jordan, Suva in Fiji, Nairobi in Kenya and Abidjan in Côte d’Ivoire. The African office will be split across two locations to better serve the continent with the largest number of countries and projects supported by the fund.

The decision marks a significant shift for the fund, which has operated from its headquarters in Songdo, South Korea, since its launch in 2013.

“This is a landmark moment for [the] GCF,” said the fund’s executive director Mafalda Duarte. “It has taken a lot of work, careful negotiation and persistent advocacy for a model that will bring us closer to the countries, to our partners and the communities we were created to serve”.

‘Less delay, more action’

The new offices are expected to act as the GCF’s front line, working more closely with governments, the private sector and civil society to improve access to climate finance and support the delivery of projects aimed at cutting emissions and strengthening resilience to climate impacts.

Welcoming the decision in a LinkedIn post, Fiji’s Permanent Secretary for the environment and climate change Sivendra Michael described it as “a win for the entire Pacific”, citing “long hours” and “tough negotiations” behind the outcome. “Less delay, more action — real support where it matters most,” he added.

    A total of 43 countries applied to host the new offices, with 16 making a final shortlist after the GCF secretariat assessed bids on criteria including cost, connectivity and the ability to attract a “world-class workforce” through quality of life and access to international schools.

    Panama emerged as the top-ranked location overall, according to a document seen by Climate Home News, while some selected hosts, including Amman and Abidjan, scored lower than rival candidates in their regions.

    Establishing the new hubs is expected to cost an initial $6.5 million, but the fund anticipates these upfront expenses will be offset over time through operational savings, including lower staff and travel costs.

    First Palestinian entity approved

    The GCF board also accredited the first organisation in Palestine that will be able to directly apply for and access funding.

    Created by the Palestinian Authority in the West Bank, the Municipal Development and Lending Fund supports local infrastructure projects and services. Working with partners, including the World Bank, it is developing projects to help communities cope with escalating climate risks such as drought and extreme heat.

    In the West Bank, which is occupied by Israel, just under half of the population lives in areas classified as having high to very high climate exposure, according to a recent study.

    The post Green Climate Fund picks locations for five developing country hubs appeared first on Climate Home News.

    Green Climate Fund picks locations for five developing country hubs

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    Island nations fight to save cultural heritage from climate change

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    Farmers and fishermen in the Maldives have long relied on an ancient calendar to guide their daily lives.

    The Nakaiy system divides the year into 27 distinct periods, each named after a star or constellation in the night sky.

    Any one period in the calendar tells you about expected weather and tidal patterns, navigational routes, and fishing conditions. The Nakaiy was created through centuries of careful observation and local knowledge, passed down through families as an essential tool for survival.

    But things are now changing. The climate crisis is leading to more extreme weather events across the Indian Ocean island nation and upending the Nakaiy calendar.

    “When you go and speak to communities and ask them what kind of impacts they are facing, a lot of elders will tell you that the weather, it doesn’t follow the calendar anymore,” explained Aishath Reesha Suhail, a programme officer in the Maldives’ Ministry of Tourism and Environment.

    As the effects of climate change worsen, it is a real prospect that the Nakaiy may be abandoned by local people, representing a major cultural loss to the Maldives.

    ‘Systemic and growing threat’

    With extreme weather becoming the norm, communities are observing a domino effect of consequences in their everyday lives. The slow onset of heritage loss is now being seen across continents, but notably among small islands in remote parts of the ocean.

    “Climate change represents a systemic and growing threat to cultural heritage worldwide,” a UNESCO spokesperson told Climate Home, adding that the World Heritage Committee has identified climate change as “one of the most significant long-term risks affecting properties across all regions.”

    UNESCO, the UN body for education, science and culture, defines the loss of cultural heritage as “the erosion of traditional knowledge systems, craftsmanship, social practices and identity, particularly where communities are displaced or livelihoods disrupted”. A clear example is historical sites and even entire islands washed into the ocean as a result of rising sea levels and coastal erosion. 

    The Maldives is dealing with such a situation now. The Koagannu Cemetery is a 900-year-old resting place, located on the country’s southernmost atoll, a mere 50 metres from the shoreline. The monument’s intricate coral gravestones are being actively threatened by the encroaching Indian Ocean. 

    The government and local community have responded to this challenge with emergency protection measures. Sandbags and concrete structures have been installed along the coastline, complemented by large numbers of palm trees to create a seawall. A wider solution is ‘beach nourishment’, a common practice in the Maldives where sand from elsewhere is brought in to replace what has been lost through erosion. Taken together, these solutions have so far protected the cemetery.

    Pacific islands push back against growing climate threats

    Among the many issues climate change creates, cultural heritage is not always front of mind. In the Maldives, one of the main barriers people face is awareness. “Most of what we are dealing with relates to the erosion of our islands along with areas such as fisheries… but we are quite limited in our capacity to do something about it,“ Suhail said.

    “We don’t understand the full breadth of the issue at present because we haven’t been able to do extensive research on the matter,” she added. However, assessing the extent of the damage – and how to respond effectively – is a key priority for the government, outlined in its latest climate plan, known as a Nationally Determined Contribution, and as part of its National Adaptation Plan process.

    Fishing is at the core of the country’s culture and identity, employing thousands of people. Most dishes include fish – “we have it for breakfast, lunch and dinner,” Suhail noted – but the climate crisis and overfishing are shifting how and when communities can fish. Tuna makes up 98% of all fish caught in the Maldives, but warmer ocean temperatures are changing migratory patterns, pushing the species into deeper, colder waters.

    As a critical economic and cultural resource, the government has outlined a range of solutions to protect the fisheries sector in its first Biennial Transparency Report to the UN. These include using real-time tracking data to improve the efficiency of fishing operations; investing in canneries to increase fish storage; and diversifying away from tuna through marine farming.

    Koagannu Cemetery, a 900-year-old resting place in the Maldives, is threatened by rising sea levels in the Indian Ocean. (Image: Ashwa Faheem) 

    Koagannu Cemetery, a 900-year-old resting place in the Maldives, is threatened by rising sea levels in the Indian Ocean. (Image: Ashwa Faheem) 

    Culture and nature go hand-in-hand

    The same pattern is playing out elsewhere.

    Palau and the Maldives are not close to one another. The two states are separated by around 4,000 miles and sit in different corners of the ocean. But both are experiencing very similar climate challenges, based on their position as a set of scattered, low-lying islands surrounded by an imposing body of blue water.

    In the same way as the Maldives, Palau’s cultural heritage is closely tied to “land, coastlines and traditional food systems,” according to Toni Soalabla, at the Palau Office of Climate Change.

    “Many of the places that hold stories, history and identity of our communities are located along the coast and are increasingly exposed to erosion and sea level rise,” she said.

    One of these places is Ngerutechei village, reportedly the oldest in Palau, and home to ancient stone paths and carvings. The village provides a glimpse into the past social values and culture of the people in this western Pacific nation.

    How Vanuatu is facing up to rising climate risks

    As part of the development of Palau’s National Adaptation Plan, the government has worked with local leaders to identify similar sites of cultural significance. The plan encourages communities to use their own knowledge to create protective measures for these sites.

    Climate change is also prompting communities to take up traditional land and food practices again. These include cultivating taro, a stable food source that has historically supported water, soil and food security on the islands. 

    “These systems developed over generations in response to local environmental conditions, so strengthening them today is both a climate adaptation measure and a way of maintaining cultural knowledge that might otherwise fade,” said Soalabla.

    Cultural practices in Palau have developed alongside the natural ecosystems that people rely on to survive. It is within this context that researchers believe adaptation policies should be created. Recognising this relationship “can strengthen both community identity and environmental resilience at the same time”, according to Soalabla.

    Taro farming is making a return to Palau as a traditional source of food security. (Image: Kiara Worth / IISD / Palau Office of Climate Change)

    Taro farming is making a return to Palau as a traditional source of food security. (Image: Kiara Worth / IISD / Palau Office of Climate Change)

    An ancient monolith in Ngerutechei village is being protected against coastal erosion. (Image: Kiara Worth / IISD / Palau Office of Climate Change).

    An ancient monolith in Ngerutechei village is being protected against coastal erosion. (Image: Kiara Worth / IISD / Palau Office of Climate Change).

    Heritage on the global stage

    The issue of cultural loss has not gone unnoticed in international climate negotiations. 

    Small island states such as the Maldives have used their role at the UN to push for greater awareness and action, with some key successes.

    In 2015, the Paris Agreement established a Global Goal on Adaptation (GGA) which recognised that countries needed to do something about climate change now and not later. However, it took six years before a framework and a set of adaptation targets were agreed at the UN climate summit in Glasgow to pursue this goal. 

    From this came the establishment of seven overall themes – from poverty eradication to access to health – to guide adaptation action and a set of around 60 indicators to measure progress against the targets.

    World leaders invited to see Pacific climate destruction before COP31

    Emilie Beauchamp, an adaptation specialist at the International Institute for Sustainable Development (IISD), said that “cultural heritage was highlighted as one of the global priorities [of the GGA Framework] and is one of the seven themes, so it is considered very important by the international community.”

    The much-debated set of indicators, only finalised in Belém at last year’s COP30, include five related to cultural heritage with a focus on preserving cultural practices and important sites that are “guided by traditional knowledge, Indigenous Peoples’ knowledge and local knowledge systems”. A spokesperson for UNESCO said the inclusion of heritage indicators “marks an important recognition that climate impacts extend beyond economic losses”. 

    While critics said the set of final indicators was rushed through by the Brazilian presidency, they now serve as guidance for national governments that wish to implement plans to protect their common heritage. The missing piece of the puzzle remains how to finance these plans – something notably absent from the Belém text, which made clear that the adaptation indicators “do not create new financial obligations or commitments, nor liability or compensation”.

    The lack of financial commitments proved disappointing for many small states grappling with how to prevent their cultural history from being entirely forgotten, especially at a time when adaptation finance remains below requirements. A recent UNEP report found that developing nations would need an estimated US$310 billion per year in 2035 to adapt to climate change, while current public financing was around $26 billion.

    At these low levels “only a small percentage of what the framework outlines could be implemented,” according to Beauchamp.

    Recent research from WRI and UNESCO found 73% of non-marine World Heritage Sites are threatened by at least one severe water risk.

    Recent research from WRI and UNESCO found 73% of non-marine World Heritage Sites are threatened by at least one severe water risk.

    The challenge of cultural heritage

    When looking at low-lying islands on a map, they can appear as specks of land amid a vast ocean. Many of the stories from these remote places go unnoticed. But the specks represent millennia of human culture that is slowly being lost to the ocean.

    While the international community has now recognised the problem and solutions exist, the recurring issue of scarce finance may prevent governments from taking sustained action. Island communities have already been forced to move home as sea levels rise, leaving behind their cultural connections to a place.

    The value of any cultural asset, or of human heritage, can be judged by how it is engaged with over generations. Without human intervention, many historical sites, language, cuisine and other local customs would become a forgotten part of history. The rapid onset of climate change brings the role of cultural heritage into sharp relief, challenging communities to decide in real time what they value, what deserves saving, and how to achieve that.

    Stories of cultural loss are not confined to small islands but it is here where the challenge is presenting most acutely. The experiences of these vulnerable nations in protecting their heritage will provide the litmus test for effective adaptation responses elsewhere.

    Adam Wentworth is a freelance writer based in Brighton, UK.

    (Main image: The Isdhoo Havitha is an ancient Buddhist monastery in the Maldives, located moments from the shoreline. Photo: Ashwa Faheem) 

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