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For the past two decades, low-level cloud cover has been declining, increasing the amount of sunlight absorbed by Earth and amplifying global warming.

As global temperatures have reached record highs in recent years, there has been concern that the decline in cloudiness may be enhancing warming more than previously expected.

In a new study, published in Atmospheric Chemistry and Physics Letters, we investigate how the decline in global cloudiness affects the Earth’s “energy imbalance” – the difference between absorbed solar energy and heat radiated into space that results in global warming.

This imbalance has more than doubled over the past 20 years, as greenhouse gases have trapped more heat in the atmosphere.

We find that, since 2003, the decrease of cloudiness has been responsible for half of the increase of Earth’s energy imbalance.

Analysing the drivers of global changes to cloud cover, we find that the decrease in cloudiness over the past two decades has been primarily driven by humans, rather than being caused by natural variations in Earth’s climate.

Taken together, our findings mean that scientists can even more confidently attribute recent warming to human activities.

Low-level clouds and warming

Low-level clouds are those that have a base below 6,500 feet (2,000 metres) above Earth and include stratus, stratocumulus and cumulus. They are typically found over large areas of the global ocean, where there is a large moisture supply from evaporation.

These clouds have a powerful impact on the Earth’s climate because they reflect a substantial fraction of incoming sunlight back into space.

By acting as the Earth’s “sunscreen”, they keep the climate cooler than it would otherwise be.

Satellite observations reveal a global decline in these low-level clouds since the turn of the millennium. This is shown in the chart below, where the black line represents the average percentage of the Earth covered by low-level clouds and the dashed line the downward trend.

Low-level cloud amount (in percent of the globe) from July 2003 to June 2024, based on the CERES-FBCT satellite product. Adapted from Ceppi et al (2026).

Our research shows that the decline in cloudiness over the past 20 years has played a major role in increasing the Earth’s energy imbalance and, therefore, warming.

The Earth’s energy imbalance is the difference between the amount of energy arriving at the Earth from the sun and what is reflected and radiated back to space.

Rising greenhouse gas emissions from human activity are upsetting this balance by trapping more energy in the atmosphere, leading to warming.

A less cloudy atmosphere also helps supercharge the energy imbalance, because it means more sunlight reaches the Earth.

In our research, we use a simple model to assess how changes in low-level clouds between July 2003 and June 2024 contributed to the Earth’s energy imbalance.

We find that, averaged globally, changes in low-level cloudiness caused an extra 0.22 watts per metre squared (W/m2) per decade of absorbed sunlight. This amounts to exactly half of the concurrent increase in Earth’s energy imbalance over the same time period.

This is shown in the chart below, where the green line represents the increase in the Earth’s energy imbalance over 2003-24 and the black line shows the contribution of low-level clouds to that trend.

Anomalies in global energy imbalance (green, from CERES-EBAF satellite observations) and contribution of low-level cloudiness changes (black, from CERES-FBCT satellite observations) from July 2003 to June 2024. Adapted from Ceppi et al (2026).
Anomalies in global energy imbalance (green, from CERES-EBAF satellite observations) and contribution of low-level cloudiness changes (black, from CERES-FBCT satellite observations) from July 2003 to June 2024. Adapted from Ceppi et al (2026).

Why is cloudiness changing?

Scientists have attributed declining cloud cover in the 21st century to three main causes.

The first is a decrease in human-caused aerosol emissions over recent decades. Aerosols – tiny, light‑scattering particles produced mainly by burning fossil fuels – influence the formation of clouds, by acting as “seeds” for cloud droplets to form.

In recent years, aerosol emissions have been reduced due to efforts to clean up air pollution, such as cleaner shipping fuel regulations. Cleaner air has resulted in a decline in cloudiness.

Second, increasing concentration of greenhouse gases in the atmosphere has led to a warmer and drier atmosphere, which also helps to dissipate clouds.

Although a warmer atmosphere generally holds more water vapour in absolute terms, what matters for clouds is the “relative humidity” of the air, which has been declining in many places. This is a measure of how “saturated” the air is, or how much water vapour the air contains compared to the maximum it could hold.

Finally, cloud cover decreases have also been linked to ocean surface warming, which affects atmospheric humidity and, thus, cloudiness. Reduced cloudiness leads to more sunlight being absorbed at the ocean surface – and more warming. This amplifying loop is known as a “cloud feedback”.

However, the exact strength of these three effects on cloud cover is still unclear.

In fact, cloud feedbacks are among the main uncertainties in climate model projections of global warming.

Attributing low-cloud cover changes

In the next step of our study, we explore how the three human-caused factors mentioned above – aerosols, greenhouse gases and cloud feedback – contributed to recent low-level cloud changes.

We also look at the extent to which cloud changes could be explained by natural climate variability, which causes substantial year-to-year fluctuations in cloudiness and energy imbalance.

To do this, we use a statistical technique known as “cloud-controlling factor analysis”.

This analysis involves calculating the sensitivity of clouds to their “controlling factors”, including meteorological variables, such as temperature, humidity and winds, as well as aerosol concentrations.

To calculate how each factor contributed to the bigger picture of declining cloud cover, we combine sensitivity calculations with observed trends in meteorology and aerosol emissions.

This analysis allows us to attribute trends in cloud cover to known physical drivers: either natural climate variability, or human activities linked to aerosols, greenhouse gases and cloud feedback.

Our research finds that about 40% of the low-level cloud decrease since 2003 was driven by warming of the ocean surface – in other words, the cloud feedback process. This is followed by the effects of greenhouse gases (21%) and aerosols (14%).

Natural climate variability accounts for just 3% of the low-level cloud trend.

(The remaining 23% of the trend cannot be explained by our statistical method. This could be due to the limitations of cloud, temperature, humidity and aerosol concentration observations.)

The chart below shows how human-driven factors – the sum of aerosol effects (red), greenhouse gas emissions (pink) and cloud feedback (burgundy) – were responsible for almost three quarters of the decrease in low-level cloudiness over 2003-24. Natural climate variability (blue), on the other hand, played a minor role.

Contributions to the decrease in global low-level cloudiness between July 2003 and June 2024, in percent of the total observed trend, from: cloud feedback (40%, burgundy), aerosols (14%, red), greenhouse gases (20%, pink), their sum (“human-driven”, 74%), and natural climate variability (blue, 3%). The remaining 23% of the cloud decrease is unexplained by our statistical method. Thin black bars denote 67% confidence ranges. Adapted from Ceppi et al (2026).
Contributions to the decrease in global low-level cloudiness between July 2003 and June 2024, in percent of the total observed trend, from: cloud feedback (40%, burgundy), aerosols (14%, red), greenhouse gases (20%, pink), their sum (“human-driven”, 74%), and natural climate variability (blue, 3%). The remaining 23% of the cloud decrease is unexplained by our statistical method. Thin black bars denote 67% confidence ranges. Adapted from Ceppi et al (2026).

Thus, our analysis indicates that, at global scales, the observed cloud decrease is primarily driven by humans, rather than being caused by natural variations in Earth’s climate.

And, since low-level clouds contribute to half of the energy imbalance increase over the same period, it follows that a significant part of recent rises in energy imbalance can also be attributed to humans.

Clouds in climate models

So, should we be concerned that this cloudiness decrease means the Earth could see more warming than already anticipated?

To answer this, we looked at whether the climate models used by scientists to project future global warming accurately simulate recent declines in low-cloud cover.

While the models produce a wide range of outcomes, we found that, on average, the simulated changes in low-level cloudiness changes are in close agreement with real-world trends.

This is reassuring, as it means the effects of low-cloud cover are already accounted for in existing warming projections.

However, questions still remain around what is driving recent increases to the Earth’s energy imbalance, which have outpaced projections made by climate models.

Our findings rule out declines in low-level clouds as the reason that climate models have been underestimating the Earth’s energy imbalance, and, as a result, warming. But it is still possible that models are underrepresenting future global warming to some extent.

Low-level clouds are just one of several drivers of changes in energy imbalance. Future work will therefore need to assess other observed and simulated drivers of energy imbalance changes: for example, the impact of upper-level clouds, or changes in water vapour or sea ice.

Finally, it is important to stress that, while our findings are reassuring, they should certainly not make us complacent about the current global warming trend. The impacts of climate change are serious enough as they are – even if there is no evidence of a missing amplifying feedback in our projections.

The post Guest post: How declining cloudiness is accelerating global warming appeared first on Carbon Brief.

Guest post: How declining cloudiness is accelerating global warming

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Climate Change

New Zealand moves to protect business with law curtailing climate litigation

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New Zealand’s parliament has adopted a controversial new law blocking a whole avenue of climate litigation and shutting down its most advanced corporate lawsuit, which has been blamed by the government for shaking business confidence and investment.

The Climate Change Response (Tort Liability) Amendment Bill, expected to take effect in the coming days after it is formally signed by the Governor-General, prevents all current and future civil claims for climate loss or harm under tort law.

Justice minister Paul Goldsmith said last week that the aim was to give businesses “certainty around their climate change obligations”, noting it would not alter the government’s responsibilities under the Climate Change Response Act 2002 nor business obligations under the Emissions Trading Scheme.

“Our response to climate change is best managed by the Government at a national level and not through piece-meal litigation in the courts,” he added in a statement.

Such litigation, he said, “risks developing a new regime that contradicts the framework Parliament has already enacted” to tackle climate change.

    Goldsmith singled out a key domestic climate lawsuit brought by Northland iwi leader and activist Mike Smith against six big companies: dairy firms Fonterra and Dairy Holdings, energy firms Genesis Energy and Z Energy, New Zealand Steel and coal mining firm BT Mining. A seventh original defendant, Channel Infrastructure, was dropped after it permanently decommissioned its Marsden Point oil refinery.

    Smith argued that these companies had caused him harm under public nuisance and negligence law, as well as a third breach of a duty to cease contributing to climate change that has yet to be tested domestically. He did not seek financial compensation, instead asking for the companies to immediately stop emitting or contributing to net greenhouse gas emissions.

    In one of the most advanced corporate climate accountability lawsuits in the world, a trial had been scheduled for April 2027 after the Supreme Court unanimously allowed the case to continue.

    Corporate lobbying in the shadows

    Smith described the passing of the bill as “deeply concerning”, particularly as it coincided with the Supreme Court hearing another of his climate lawsuits. In that case, Smith v Attorney-General, he argues that the government’s response to climate change and its impacts on Māori communities in particular breaches rights to life and culture.

    “That timing raises profound questions about the separation of powers and the rule of law,” said Smith. “Whatever one’s view of the merits of these cases, it is deeply troubling when parliament intervenes to remove a legal pathway while the courts are actively considering fundamental questions about climate responsibility, rights and the crown’s obligations.”

    The bill – which says that no person (including the government) can be found liable in tort for emissions-related climate change effects – followed major lobbying efforts by the companies defending themselves in Smith’s lawsuit. They outlined a proposed legal amendment in a briefing note to the government in 2024.

    The centre-right government has been fiercely criticised over its lack of transparency in relation to this lobbying activity. The national ombudsman recently found that the Prime Minister’s Office effectively withheld information requested by the Environmental Law Initiative about meetings, discussions and conversations regarding Smith’s case.

    Green groups fail to stop bill

    The bill sparked huge concern among environmental campaigners in New Zealand and elsewhere. Greenpeace Aotearoa called it a “shocking abuse of executive power” and the vast majority of submissions to a parliamentary inquiry said it should be rejected.

    But in the end, it was adopted with little resistance, moving relatively smoothly through parliament, passing its third reading by 67 votes to 53. Sam Bookman, climate law lecturer at Melbourne Law School, told Climate Home News he was not surprised by this, given that the coalition government has a secure majority.

    A complaint has been made to the UN special rapporteur on climate change and human rights by Smith, the National Iwi Chairs Forum Pou Tikanga and youth coalition Climate Clinic Aotearoa over what they see as the government’s heavy-handed approach. Smith is also challenging the new law in yet another lawsuit.

    “Pathetic”: New Zealand plans to barely cut emissions between 2030 and 2035

    Bookman thinks it “very unlikely” that such a challenge will succeed, noting that New Zealand’s constitution is firmly anchored in parliamentary sovereignty.

    But the expert in climate law does not see the bill as the end of legal action in the country, noting that New Zealand has a “sophisticated climate litigation landscape with a growing number of specialist and experienced lawyers and NGOs”.

    The country is also approaching its next general election in November, and some opposition parties have pledged to restore access to the courts if elected.

    Amanda Larsson, global project lead on agriculture for Greenpeace International, said: “This law deserves to be tested, and I strongly encourage the international climate litigation community to unite and help defend New Zealanders’ fundamental right to hold polluters accountable before this becomes a global blueprint.”

    Copycat legislation on the rise

    New Zealand’s move is part of a small but growing legislative effort to shut down climate litigation around the world.

    In the US, Republican politicians introduced legislation in the House and Senate in April that would shield fossil fuel firms from climate liability lawsuits. Similar laws have already been passed at state level in Tennessee, Utah, Iowa and Louisiana.

    The German state of Bavaria has put forward a similar proposal to the Federal Council, aiming to block private climate claims as well as the recognition and enforcement of foreign judgments imposing such liability. There are also proposals to limit available remedies and actions in the Netherlands and Belgium.

    UN General Assembly backs “climate obligations” set by world’s top court

    Bookman said he expects more efforts to counter climate damages litigation and advised plaintiffs to think about how to respond, including drawing on broader support in opposing them.

    “Even though it’s very hard for plaintiffs to win these types of cases, companies are very eager to avoid the expense, embarrassment and political accountability that come even with unsuccessful lawsuits,” he said.

    The post New Zealand moves to protect business with law curtailing climate litigation appeared first on Climate Home News.

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    Indonesia’s nickel production cuts are not enough to create a sustainable industry 

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    Bhima Yudhistira Adhinegara is the Executive Director of the Center of Economic and Law Studies (CELIOS), an Indonesia-based economic think tank. Muhammad Zulfikar Rakhmat is the Director of the China-Indonesia desk at CELIOS. 

    Indonesia produces around 60% of the world’s nickel, a metal used to manufacture batteries for electric vehicles (EVs) – more than any other country in the world. But in 2026, the government sharply reduced how much of its nickel can be extracted from the ground.

    Production quotas were reduced by around 40% this year compared to 2025. Weda Bay, the largest nickel mine on Earth, had its allowance cut by more than 70% and exhausted its full-year quota by the end of May, halting mining entirely; it cannot resume large-scale extraction until next year unless regulators grant an extension.

    The policy has sparked a vivid debate in Indonesian policy circles: how can the country shift its strategy from a decade of mining vast quantities of cheap nickel to producing a high-value and low-carbon material that the rest of the world wants for EV batteries.

    The cuts aren’t a silver bullet to clean up Indonesia’s nickel industry, whose smelters are powered by coal – the most polluting fossil fuels. But alongside stricter enforcement of environmental rules, it is one side of efforts to produce more sustainable nickel for a premium.

    Restricting Indonesia’s nickel output

    Production quotas were introduced to stop the collapse of nickel prices because of oversupply in the market. Prices had fallen more than 40% in 2023 alone and kept sliding as Indonesian supply kept growing, hitting a four-year low of around $13,900 a ton in late 2025.

    Critics called the recent tightening of production quotas proof that Indonesia’s nickel strategy has failed, arguing that the industry shouldn’t need to throttle its own output to survive. But when assessed against what the policy was supposed to do – push up nickel prices – it has worked. Prices jumped to $20,000 a ton in May, the highest since 2024.

      Chinese industry groups representing companies that have invested billions to mine and refine the country’s nickel were furious, warning Indonesia’s president Prabowo Subianto that the cuts put $50 billion worth of investment at risk. But much of that Chinese capital is sunk into smelters and processing plants built specifically to run on Indonesian ore, and cannot simply be moved elsewhere. That gives Jakarta more room to hold its ground than the warning suggests.

      Stronger environmental enforcement

      Since the start of the year, Indonesia’s forestry task force has seized more than four million hectares of land from mines and plantations operating illegally in protected forests, collecting over two trillion rupiah ($113 million) in fines.

      This included 148 hectares seized from Weda Bay for lacking a forestry permit. The share of nickel produced from illegal small-scale mining also fell from about a quarter in 2022 to roughly 10% by 2024.

      The crackdown responds to serious environmental damages in the nickel industry. On Obi Island, a waste pond collapsed after heavy rain in June 2025, flooding three villages and killing a resident. Internal company tests found chromium-6 – a carcinogen – in the water, in quantities far above the legal limit. The footprint of another mine near Raja Ampat, which is home to some of the world’s richest coral reefs, grew 60-fold in just eight years.

      A coastal village is wedged between the sea and a large nickel mine in Indonesia
      The fishing villages of Tapunggaya in Sulawesi, Indonesia, are squeezed between the sea and an expanding nickel mine (Photo by Garry Lotulung/NurPhoto)

      The market is responding to early cleanup efforts. Low-carbon nickel now sells for a real premium, roughly $18,800 to $19,300 a ton compared with $17,900 to $18,300 otherwise, as carmakers seek to source cleaner materials to comply with the European Union’s new emissions rules for imports.

      In turn, this is incentivising the industry to do more to green its operations. Vale Indonesia’s smelter in South Sulawesi now runs almost entirely on hydropower, for example.

      None of this addresses coal use, however. Major Indonesian nickel producers still emitted an estimated 15 million metric tons of greenhouse gases in 2023. Indonesia may be cracking down on illegal mining and rewarding cleaner producers but it is still running its mines on the dirtiest fuel available.

      Unequal benefits

      For Indonesia to truly benefit from producing cleaner and high-value nickel, it needs to reap the economic benefits too. Although the industry has boosted the country’s economic growth, the reality on the ground tells a different story.

      Konawe in Southeast Sulawesi is home to a major smelting complex. Growth in the district jumped from 6% to 22% between 2015 and 2023, driven almost entirely by the nickel industry, according to a study by the Lowy Institute study. At the same time, poverty levels increased slightly and unemployment remained unchanged.

        In Halmahera, another epicentre of the nickel industry, spending by the poorest fifth grew just 5% between 2019 and 2022, compared with 28% for the wealthiest fifth, according to a separate study.

        Part of the reason for this inequality is the system for transferring mining royalties to district authorities where the mines are located. In theory, they are entitled to the largest share. But in practice, payments are delayed, companies routinely dispute what they owe and royalties are pooled and distributed across a larger area.

        The Natural Resource Governance Institute has found that decentralisation handed local governments power to approve new mines faster than they could build their capacity to manage them. Higher output raises national income on paper, but local governments remain constrained by fiscal rules and infrastructure costs that scale with mining.

        None of this makes the 2026 quota cuts a mistake. Indonesia has every right to defend its pricing power over a resource it controls. But limiting extraction isn’t going to fix underlying issues around environmental enforcement and revenue-sharing. That requires rules that are consistently enforced, royalties that reach communities living by the mines, and a plan to wean smelters off coal.

        The post Indonesia’s nickel production cuts are not enough to create a sustainable industry  appeared first on Climate Home News.

        Indonesia’s nickel production cuts are not enough to create a sustainable industry 

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        Risk of “catastrophic” oil spill reaching Kimberley coast found in Woodside’s Scott Reef gas drilling plans

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        SYDNEY, Monday 24 August 2026 – New analysis of Woodside modelling released by Greenpeace Australia Pacific and Environs Kimberley has revealed the oil and gas corporation’s plans to drill at Scott Reef could cause an oil spill up to 30 times bigger than the 2009 Montara disaster, impacting the Kimberley coastline and reaching as far as Indonesia.

        The new analysis details the “catastrophic” oil spill risk put to environmental regulators for approval by Woodside in its Browse to North West Shelf Project (Browse) plans, the worst-case scenario being a blowout directly below Scott Reef, polluting whale migratory pathways and covering isolated turtle nesting ground with oil condensate.

        An FOI application (F348) revealed the federal environment department (DCCEEW) asked offshore oil and gas regulator NOPSEMA to look into the oil spill risk in 2025. NOPSEMA’s response to the application refused access to its report, and one document shows DCCEEW sought further advice this year.

        Greenpeace and Environs Kimberley are calling on the Federal Government to publicly release the NOPSEMA report given the risk of an uncontrolled release of oil condensate from directly below Scott Reef.

        Hannah Schuch, Senior Campaigner at Greenpeace Australia Pacific, said: “Woodside is aware that drilling at Scott Reef risks a massive oil spill that would have severe, far-reaching consequences. It appears environmental regulators are aware too.

        “The state and federal governments need to take this risk from Woodside’s drilling plans seriously, as they could end up allowing the worst oil spill in Australian history.

        “The pygmy blue whales that migrate up and down the WA coast with their newborns each year could be swimming and feeding in toxic, oil-slicked water. Woodside’s proposal to drill at Scott Reef is an environmental disaster waiting to happen, and the WA and federal governments have one surefire way to prevent catastrophe — reject Browse.”

        Martin Prichard, Executive Director at Environs Kimberley, said: “A catastrophic oil spill by Woodside would be disastrous not just for marine life in the area but also for the Kimberley’s $500 million tourism industry.

        “The state and federal governments will see five marine parks on the Kimberley coast included in the risk area of a catastrophic Woodside oil spill.

        “The Montara oil spill was disastrous for West Timor with the toxic oil destroying seaweed farmers’ livelihoods. The Kimberley dodged a bullet with Montara, we were lucky the spill didn’t head our way. Myself and a crew flew over the Montara oil spill and followed it as far as we could. It was like a scene from a disaster movie.”

        After the WA Environmental Protection Authority deemed Browse “unacceptable” due, in part, to oil spill risk, Woodside submitted a mitigation plan based on technology that has never been used “in anger”, a weakness stated in an independent expert review of the plan.

        Professor Richard Steiner, independent oil spill expert, said: “A large offshore spill is impossible to effectively contain or recover. Historically, only 2-6% of total spill volume is recovered and the ecological injury from the release of toxic hydrocarbons in the sea can be severe, extensive, and long-term.

        “Here in Alaska, government research concludes that several marine populations injured by the 1989 Exxon Valdez oil spill, including whales, fish, and seabirds, are still not recovering today, 37 years later. We should expect similar long-term ecological impacts in Western Australia if there were to be a major oil spill. The only sure way to avoid the risk of a catastrophic marine oil spill is to not develop oil and gas projects in marine environments.”

        -ENDS-

        Media contact

        Emma Sangalli on emma.sangalli@greenpeace.org or 0431 513 465

        Risk of “catastrophic” oil spill reaching Kimberley coast found in Woodside’s Scott Reef gas drilling plans

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