Published

8 months ago

August 11, 2025

Alice Rush

An uptick in heat extremes, driven by human-caused climate change, has caused tropical bird populations to decline by up to 38% since the 1950s, according to a first-of-its-kind analysis.

The study combines ecological and climate attribution techniques to trace the fingerprint of fossil-fuelled climate change on declining wildlife populations.

It shows that an increase in heat extremes driven by climate change has caused tropical bird populations to decline by 25-38% in the period 1950-2020, when compared to a world without warming.

The findings could help to explain why tropical bird numbers have declined even in pristine rainforests, a phenomenon that previously mystified biologists, the scientists say.

‘Chance encounter’

Over the past few decades, an emerging field of science known as “climate attribution” has used a standardised set of techniques to trace the fingerprint of human-caused warming on different elements of the climate system, ranging from worsening extreme weather events to episodes of glacier melt.

The new research, published in Nature Ecology and Evolution, is the first to use climate attribution techniques to detect the fingerprint of climate change on declining wildlife populations.

The study came about following a “chance encounter” between lead author Dr Maximilian Kotz, a climate scientist at the Barcelona Supercomputing Center in Spain, and his co-authors, who are biodiversity experts at the University of Queensland in Australia, while Kotz was completing a research stay in Australia.

Kotz says to Carbon Brief:

“As far as we are aware, this is the first animal climate attribution study.”

The researchers decided to focus on birds, rather than other animal species, as they have the “best available data, covering a good range of different species and geographies”, he adds.

Heat extremes

The authors examine how an intensification of heat extremes could have impacted bird populations, while controlling for other factors known to affect wildlife, including average temperature increase and human pressures, such as land-use change.

Episodes of extreme heat are known to have an immediate and long-lasting impact on birds, Kotz says:

“High temperature extremes can induce direct mortality in bird populations due to hyperthermia and dehydration. Even when they don’t [kill birds immediately], there’s evidence that this can then affect body condition which, in turn, affects breeding behaviour and success.”

Using statistical techniques, the scientists first analyse historical records to identify how bird populations have responded to fluctuations in climate, including heat extremes, over 1950-2020.

The team sourced global data on bird populations from the database that underlies the Living Planet Index, put together by the environmental charity WWF. They note it is the most comprehensive database available, but still has “clear geographic biases”, with global north regions better represented than those in the global south.

They use an attribution framework to estimate the extent to which human-caused warming influenced the changes in heat extremes observed in that time period, then calculate the impact of these climate-change-driven heat extremes on bird population changes from 1950-2020.

(The authors defined “heat extremes” as temperatures within the top 1% of daily temperatures over 1940-70, with data taken from ERA5, a global reanalysis dataset, which combines data from weather stations, satellites and model output.)

To understand how this would compare to a world without climate change, the researchers subtract this impact from the historical records.

Comparing their results to the counterfactual world without climate change allowed them to quantify how bird populations have changed as a result of human-driven increases in heat extremes.

Mapped

The research finds that human-driven heat extremes have had “strong negative impacts” on bird population numbers, with those residing at lower latitudes being the most affected.

The map below shows the percentage change in bird population abundance attributed to heat extremes over 1950-2018, when compared to a world without climate change.

On the map, dark red shows large decreases in population abundance, while light blue indicates small increases. (Abundance refers to the number of individual animals in a given population.)

The percentage change in bird population abundance attributed to heat extremes over 1950-2018, when compared to a world without climate change. Credit: Kotz et al. (2025)

The research finds that birds in the tropics have experienced the largest declines attributable to heat extremes.

It concludes that an uptick in heat extremes has caused tropical bird abundance levels to decline by 25-38% in the period 1950-2020, when compared to a world without warming.

The range in the size of that impact reflects the results of different models, which each use slightly different techniques to simulate changes to bird populations, Kotz says.

Tropical turmoil

In their paper, the authors note that their finding that tropical birds have experienced the most substantial declines are “consistent” with other studies indicating that “birds in these regions may be closer to the thermal limits at which impacts start to occur”.

They add that the findings are “particularly pertinent, given recent documentation of declining tropical bird populations, even in undisturbed habitats”.

One previous study found that in a “relatively undisturbed” part of the Amazon rainforest, bird abundance declined by more than 50% from 2003 to 2022. Similar results were found in a forest in Panama.

The authors of the new study say:

“The source of such declines have been noted as unknown, yet they are of a similar order of magnitude to our estimates of the impacts of intensified heat extremes.”

Their results suggest that “in tropical realms, climate change impacts on bird populations may already be comparable to land pressures that lead to habitat destruction and degradation”, the authors say.

This has “potential ramifications” for commonly proposed conservation strategies, such as increasing the amount of land in the the tropics that is protected for nature, they continue:

“While we do not disagree that these strategies are necessary for abating tropical habitat loss…our research shows there is now an additional urgent need to investigate strategies that can allow for the persistence of tropical species that are vulnerable to heat extremes.”

In some parts of the world, scientists and conservationists are looking into how to protect wildlife from more intense and frequent climate extremes, Kotz tells Carbon Brief.

He references one project in Australia which is working to protect threatened wildlife following periods of extreme heat, drought and bushfires.

Informing forecasts

As well as shedding light on what could be behind the rapid decline of birds in the tropics, the findings also underscore the importance of examining changes in climate extremes, rather than just annual global temperature rise, says Prof Alex Pigot, a biodiversity scientist at University College London (UCL), who was not involved in the research. He tells Carbon Brief:

“Most of the models that have been used to make projections of risk to biodiversity under future climate change use long-term climate averages and so the results of this study suggest that our existing risk assessments could be missing these critical impacts of climate change.

“We urgently need to address this and develop early warning systems to be able to anticipate in advance where and when extreme heatwaves and droughts are likely to impact populations – and also rapidly scale up our monitoring of species and ecosystems so that we can reliably detect these effects and feed this information back into our models to refine our future projections for biodiversity.”

Dr Peter Soroye, a biodiversity scientist at the Wildlife Conservation Society Canada, who was also not involved in the research, agrees:

“It’s not just that the climate is getting gradually warmer every year with climate change, it’s that climate change is also driving increasingly frequent and severe extreme temperature events that are putting wildlife at risk.

“As we more fully understand the importance of extremes, it seems increasingly important to consider them when we model or project changes in biodiversity over time.”

The post Fossil-fuelled heat has caused tropical birds to decline by ‘up to 38%’ since 1950s appeared first on Carbon Brief.

Fossil-fuelled heat has caused tropical birds to decline by ‘up to 38%’ since 1950s

Climate Change

Broken debt system must be fixed to confront future climate shocks

Published

11 hours ago

April 14, 2026

Alice Rush

Mae Buenaventura is the manager of the debt justice programme of the Asian Peoples’ Movement on Debt and Development, a regional alliance of peoples’ movements, community organizations, coalitions, NGOs and networks

A potentially historic shift in public debt governance is set to unfold in Washington DC this week as Global South governments take a collective stand to stop a “silent killer” of development financing.

The first-ever UN-hosted borrowers’ forum will officially be launched on April 15 on the sidelines of the 2026 Spring Meetings of the International Monetary Fund (IMF) and the World Bank. Led by five convening countries – Zambia, Egypt, Nepal, the Maldives and Pakistan – the initiative is one of the key wins of last year’s 4th Financing for Development Conference (FFD4) in Sevilla, Spain.

The forum’s mandate is to establish a platform for borrower countries, supported by a UN secretariat, “to discuss technical issues, share information and experiences in addressing debt challenges, increase access to technical assistance and capacity-building in debt management, coordinate approaches and strengthen borrower countries’ voices in the global debt architecture”.

Instead of facing lenders alone, these countries will now use a UN-backed platform to share technical expertise and coordinate their approach to a global debt system that is fundamentally broken.

Debt grips climate-vulnerable nations

The human cost of the current debt architecture is staggering. According to the UN trade and development agency, UNCTAD, more than 40% of the global population – roughly 3.4 billion people – live in countries where the government is forced to spend more on debt payments than on the health, education and social protection of its citizens.

In so-called low-income countries, governments spend an average of 7.5% of their total budgets on debt service, with interest payments consuming up to 20% of total government revenue in these regions.

The Philippines is a case study in this financial stranglehold. It is part of a global majority forced to watch its public services crumble and infrastructure lag while its wealth is siphoned off to satisfy foreign lenders.

The policy of automatic appropriations – a legacy of the rule of late former President Ferdinand Marcos Sr. – mandates that debt servicing takes precedence over any other public expenditure, effectively placing the demands of lenders above the needs of the Filipino people. Even as it faces a $1.5 trillion regional financing gap to achieve the Sustainable Development Goals (SDGs) by 2030, its hands remain tied by a legal framework that values credit ratings over human lives.

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As a “middle-income country” (MIC), the Philippines is stuck in a frustrating purgatory. It is often deemed “too wealthy” for the G20’s debt-relief framework, yet too poor to absorb global economic shocks. Last year, Finance Undersecretary Joven Balbosa hit the nail on the head when he called for support that goes “beyond the simplistic income categorization” that ignores a country’s actual vulnerabilities.

Without an inclusive and equitable global debt architecture, nations including the Philippines are left to navigate catastrophic climate risks and economic shocks with zero fiscal breathing space.

No respite during climate disasters

The regional evidence of this systemic failure is everywhere. Take Pakistan, which in 2022 was hit by catastrophic flooding that submerged a third of the country and caused billions in losses. Despite this climate-driven disaster, World Bank data shows that Pakistan made payments in 2023 of $11.8 billion for public and publicly guaranteed (PPG) external debt, while its PPG external debt reached $93 billion that same year, surpassing pre-pandemic debt of $87 billion (2020).

Sri Lanka followed IMF prescriptions throughout 16 lending programs since 1991, only to become the first Asian country this century to default. Its MIC status prevents application for debt relief and restructuring measures. Today, the Sri Lankan people bear the brunt of harsh conditionalities, including raising VAT from 8% to 15%, slashing food and fuel subsidies, and the erosion of hard-earned worker pensions.

Residents sit in a Rescue 1122 boat as they evacuate from the flooded area, following monsoon rains and rising water levels of the Chenab River, in Qasim Bela village on the outskirts of Multan in Punjab province, Pakistan, September 11, 2025. REUTERS/Quratulain Asim

Currently, the global rules of lending and borrowing are set by a “creditors’ club” composed of the IMF, the World Bank and the Global Sovereign Debt Roundtable it set up, and the Paris Club.

These institutions measure “debt sustainability” through a narrow lens of a country’s capacity to make timely repayments. They largely ignore internal economic inequalities, gender disparities and the existential threat of climate change.

Crises should trigger debt service cancellation

By organising the new borrowers’ forum, the Global South is signalling that the era of passive “standard-setting” by lenders is over.

The ultimate goal for global civil society and debt justice movements is the establishment of a UN Debt Convention; a democratic, binding and inclusive framework that governs both lenders and borrowers. This mechanism would ensure that debt restructuring and cancellation are sufficient to allow countries to fulfill their international human rights obligations and implement necessary climate actions.

Green Climate Fund picks locations for five developing country hubs

To be truly transformative, debt sustainability analyses must align with human rights and sustainable development needs. This means conducting impact assessments – both before and after loans are issued – to identify “illegitimate” debts that do not benefit the public.

Crucially, we need an automatic debt service cancellation mechanism that triggers during extreme climatic, environmental or health shocks. We also need a binding global debt registry to ensure that every loan is transparent and subject to public scrutiny.

Whether the borrowers’ forum becomes a true milestone depends on its courage to challenge the status quo. We can no longer allow debt to act as a “silent killer” of our future. It is time to demand a financial system that serves humanity, not just the balance sheets of the powerful.

The post Broken debt system must be fixed to confront future climate shocks appeared first on Climate Home News.

Broken debt system must be fixed to confront future climate shocks

Climate Change

Join Greenpeace to save Scott Reef from Woodside’s dirty gas

Published

11 hours ago

April 14, 2026

Alice Rush

Greenpeace and allies will be protesting outside Woodside’s Annual General Meeting to show the WA and federal governments strong community opposition to Woodside’s proposal to drill for gas at Scott Reef.

What: Protest outside Woodside Energy’s Annual General Meeting

When: 8am Thursday 23rd April 2026Where: Kagoshima Park (on the corner of Great Eastern Highway and Bolton Avenue)

RSVP now and join the protest

What’s at stake

Scott Reef is a pristine ocean ecosystem off the north-west coast of Australia.

It is home to endangered and endemic species, including pygmy blue whales and the dusky sea snake, and a nesting ground for green sea turtles. Scott Reef is a place of extraordinary natural beauty, and a vital marine environment that supports a wide range of marine life.

What Woodside is proposing

Dirty fossil fuel corporation, Woodside Energy, is seeking approval to drill more than 50 gas wells underneath and around Scott Reef as part of its Browse project.

The gas would be extracted and transported to the Burrup Hub, the most polluting fossil fuel project in Australia. This proposal would industrialise the doorstep of Australia’s largest freestanding oceanic reef system – threatening the marine life that relies on it and the climate.

Why this can’t go ahead

The WA Environmental Protection Authority has already identified the risks of this project as “unacceptable”, issuing a preliminary rejection.

Serious concerns include:

The risk of an oil spill
Impacts on pygmy blue whales
Damage to green sea turtle nesting grounds

These risks are severe, and potentially irreversible. But the decision hasn’t been made yet. The project is still being assessed.

The Federal Environment Minister is approaching a decision that will determine whether Scott Reef is protected – or vulnerable to decades of industrial gas destruction.

This is a defining moment.