Hundreds of scientists in dozens of institutions are embarking on the next phase of the world’s largest coordinated climate-modelling effort.
Climate-modelling groups use supercomputers to run climate models that simulate the physics, chemistry and biology of the Earth’s atmosphere, land and oceans.
These models play a crucial role in helping scientists understand how the climate is responding as greenhouse gases build up in the atmosphere.
For four decades, the Coupled Model Intercomparison Project (CMIP) has guided the work of the climate-modelling community by providing a framework that allows for millions of results to be collected together and compared.
The resulting projections are used extensively in climate science and policy and underpin the landmark reports of the Intergovernmental Panel on Climate Change (IPCC).
Now, the seventh phase of CMIP – CMIP7 – is underway, with more than 30 climate-modelling centres expected to contribute more than five million gigabytes of data – so much that downloading it using a fast internet connection would take two and a half years.
Here, we look at what is new for CMIP7, including its model experiments, updated emissions scenarios and “assessment fast track” process.
What is CMIP?
Around the world, climate models are developed by different institutions and groups, known as modelling centres.
Each model is built differently and, therefore, produces slightly different results.
To better understand these differences, CMIP coordinates a common set of climate-model experiments.
These are simulations that use the same inputs and conditions, allowing scientists to compare the results and see where models agree or differ.
The figure below shows the countries that have either produced or published CMIP simulations.
During this time, scientists use new and improved models to run experiments from previous CMIP phases for consistency, as well as new experiments to investigate fresh scientific questions.
These simulations produce a trove of data, in the form of variables – such as temperature, rainfall, winds, sea ice extent and ocean currents. This information helps scientists study past, present and future climate change.
As scientific understanding and technical capabilities improve, models are refined. As a result, each CMIP phase incorporates higher spatial resolutions, larger ensembles, improved representations of key processes and more efficient model designs.
CMIP7 objectives
Each CMIP phase has an “experimental design” that outlines which climate-model experiments should be run and their technical specifications, including the time period the models should simulate.
The CMIP7 experimental design has several components.
As in CMIP6, for a modelling centre to contribute, they are asked to produce a suite of experiments that maintain continuity across past and future CMIP phases.
This suite of experiments is known as the “diagnostic, evaluation and characterisation of klima” (DECK) and is used to understand how their model “behaves” under simple, standard conditions. These experiments are designed and requested directly by CMIP’s scientific governing panel.
Alongside the DECK, CMIP also incorporates experiments developed by model intercomparison projects (MIPs) run by different research communities. For example, experiments exploring what the climate could look like under different levels of emissions or those that explore how sea ice might have changed between the last two ice-ages.
Currently, CMIP is working with 40 MIPs. These groups investigate specific scientific questions at their own pace, rather than on timelines prescribed by CMIP.
Running a large number of simulations can take modelling centres a long time. To speed up the process, CMIP7 has launched the “assessment fast track”.
This is a small subset of CMIP7 experiments, drawn from past and present community MIPs, identified through community consultation as being critical for scientific and policy assessments.
Data from the assessment fast track will be used in the reports that will together form the seventh assessment (AR7) of the IPCC.
It will also be used as an input by other groups that create climate information, including organisations involved in regional downscaling and modelling climate impacts and ice-sheet changes.
The figure below shows the different components of CMIP7. It shows how a subset of CMIP7 experiments will be delivered on an accelerated timeline, while the majority of experiments will be led by MIPs.
CMIP7 experiments
There are three categories of experiments set to take place in CMIP7:
- Historical experiments, which are designed to improve scientific understanding of past climates. Model runs exploring the recent historical period also allow scientists to evaluate the performance of models by checking how well they replicate real-world observations.
- Prediction and projection experiments, which allow scientists to analyse what different climates could look like under varying levels of greenhouse gas emissions, as well as near-term (10-year) prediction experiments.
- Process understanding experiments, which are designed to better understand specific processes and isolate cause-and-effect relationships. For example, a set of experiments might change the emissions of one greenhouse gas at a time to see how much each pollutant contributes to warming or cooling the climate.
Modelling centres typically produce and publish their data for the historical and projection experiments first.
CMIP expects the first datasets to be available by this summer, with broader publication recommended by the end of the year, in time to be assessed by IPCC AR7 authors.
Drafting of the reports of AR7 is currently underway. However, countries are yet to agree on the timeline for when they will be published. This presents a challenge for the climate-modelling community, given the difficulties of working with a moving deadline.
(For more on the ongoing standoff between countries around the timing of publication of the reports, read Carbon Brief’s explainer.)
New emissions scenarios
Scientists use emissions scenarios to simulate the future climate according to how global energy systems and land use might change over the next century.
Crucially, these scenarios – also known as “pathways” – are not forecasts or predictions of the future.
The group tasked with designing the scenarios for CMIP phases, as well as producing the “input files” for climate models, is the “scenario model intercomparison project”, or ScenarioMIP.
In a new paper, the group has set out the new set of scenarios for CMIP7:
- High (H): Emissions grow to as high as deemed plausibly possible, consistent with a rollback of current climate policies. This scenario will result in strong warming.
- High-to-low (HL): Emissions rise as in the high scenario at first, but are cut sharply in the second half of the century to reach net-zero by 2100.
- Medium (M): Emissions consistent with current policies, frozen as of 2025, leading to a moderate level of warming.
- Medium-to-low (ML): Emissions are slowly reduced, eventually reaching net-zero emissions by the end of the century.
- Low (L): Emissions consistent with likely keeping warming below 2C and not returning to 1.5C before the end of the century.
- Very low (VL): Emissions are cut to keep temperatures “as low as plausible”, according to the paper. This scenario limits warming to close to 1.5C by the end of the century, with limited overshoot beforehand.
- Low-to-negative (LN): Emissions fall slightly slower than in the VL scenario, with temperatures just rising above 1.5C. Emissions then rapidly drop to negative to bring warming back down.
The figures below show the emissions (left) and the estimated global temperature changes (right) under the seven new scenarios for CMIP7, from the low-to-negative emissions scenario (turquoise) to a high-emissions scenario (brown).
As a set, the ScenarioMIP scenarios “cover plausible outcomes ranging from a high level of climate change (in the case of policy failure) to low levels of climate change resulting from stringent policies”, the paper says.
Compared to the scenarios in CMIP6, the range in future emissions they cover is now narrower, the authors say:
“On the high-end of the range, the CMIP6 high emission levels (quantified by SSP5-8.5) have become implausible, based on trends in the costs of renewables, the emergence of climate policy and recent emission trends…At the low end, many CMIP6 emission trajectories have become inconsistent with observed trends during the 2020-30 period.”
Put simply, progress on climate policies and cheaper renewable technologies means that scenarios of very high emissions have now been ruled out.
However, this progress has not been sufficient to keep society on track for the Paris Agreement’s 1.5C goal. The paper notes that, “at this point of time, some overshoot of the 1.5C seems unavoidable”.
The change to the high end of the scenarios has sparked misleading commentary in the media and on social media – even from US president Donald Trump. A Carbon Brief factcheck unpacks the debate.
Also notable in the new scenarios is the “low-to-negative” pathway, which has the explicit feature of emissions becoming “net-negative”. In other words, through carbon dioxide removal (CDR) techniques, society reaches the point at which more carbon is being taken out of the atmosphere than is being added through greenhouse gas emissions.
Reaching net-negative emissions is fundamental to “overshoot scenarios”, where global warming passes a target and then is brought back down by large-scale CDR.
Overshoot scenarios allow scientists and policymakers to investigate the impacts of a delay to emissions reductions and better understand how the world might respond to passing a warming target. This includes the question of whether some impacts of climate change, such as ice sheet melt, are reversible.
CMIP has encouraged modelling centres to run simulations using the “high” and “very low” scenarios first to ensure downstream users of the data – including groups working on regional climate projections (CORDEX), climate impacts modelling (ISIMIP) and ice-sheet modelling (ISMIP) – have enough time to produce their data for IPCC reports.
These two scenarios were selected as they sit at opposite ends of the spectrum of climate outcomes. The high scenario will demonstrate how models behave under high emissions, while the very low scenario will demonstrate how models behave when emissions are rapidly reduced.
CMIP has recommended that modelling centres then run the “medium” and “high-to-low” scenarios. The remaining scenarios should then follow and no official recommendation has been made yet on their production order.
Other new features
In addition to the assessment fast track and new scenarios, CMIP7 has a number of other new developments.
Updated data for simulations
Climate models use input datasets to define the set of external drivers – or “forcings” – that have caused the global warming observed so far. These drivers include greenhouse gases, changes to incoming solar radiation and volcanic eruptions.
CMIP recommends modelling groups use the same input datasets, as this makes it easier to compare model results.
In CMIP7, the historical forcing datasets available for modelling groups to use have been improved to better represent real-world changes and extended closer to the present day. The historical simulations will be able to simulate the past climate from 1850 through to the end of 2021, whereas CMIP6 only simulated the past climate through to 2014.
CMIP is also planning to extend these historical datasets through to 2025 and maybe further throughout the course of CMIP7.
Emissions-driven simulations
CMIP7 introduces a new focus on CO2 emissions-driven simulations, providing a more realistic representation of how the climate responds to changes in emissions.
In older generations of climate models, atmospheric levels of CO2 and other greenhouse gas concentrations have been needed as an input to the model. These levels would be produced by running scenarios of CO2 emissions through separate carbon cycle models. The resulting climate-model runs were known as “concentration-driven simulations”.
However, many of the latest generation of models are now able to run in “emissions-driven mode”. This means that they receive CO2 emissions as an input and the model itself simulates the carbon cycle and the resulting levels of CO2 in the atmosphere.
This development is important, as climate policies are typically defined in terms of emissions, rather than overall atmospheric concentrations.
This new development in modelling will enable a more realistic representation of the carbon cycle and a better understanding of how it might change under different levels of warming.
Enhanced model documentation and evaluation
All CMIP7 models will be required to supply standardised model documentation that ensures consistency across model descriptions and makes it easier for end users to understand the data.
Additionally, CMIP scientists have developed a new open-access tool that dramatically speeds up the evaluation of climate models.
This “rapid evaluation framework” allows researchers to compare model outputs with real-world observations, providing immediate insight into model performance.
The post Guest post: How CMIP7 will shape the next wave of climate science appeared first on Carbon Brief.
Guest post: How CMIP7 will shape the next wave of climate science
Australia’s network of marine parks is the largest in the world, covering more than half (52%) of Australia’s Commonwealth waters. You could be forgiven for assuming that a marine park is much like a national park on land: a highly protected place where people can enjoy nature while conservation efforts help habitats recover and wildlife thrive. You wouldn’t expect someone to bulldoze a national park, so why should they be allowed to bottom trawl in a marine park?
The reality is that not all marine parks are equally protected. Australia’s Marine Parks Network is divided into different zoning categories, with each zone determining which activities are permitted and the level of protection provided.
More than half of the Commonwealth Marine Parks Network allows industrial activities like oil and gas mining, and industrial fishing.
Our survival, and the survival of our planet, depends on the ocean. The ocean produces more oxygen than all of our forests combined, sustains communities and regulates the earth’s temperature. It’s home to wondrous wildlife and important ecosystems like coral reefs and kelp forests.
We love our big blue backyard
Australia’s ocean is teeming with life that is found nowhere else on earth. Schools of colourful fish, vibrant coral reefs, endemic shark nurseries, pods of dolphins, families of whales, playful seal pups and threatened Jurassic-era turtles call Australian waters home.
Since time began, from the turquoise waves to the deep blue, the ocean has connected our shorelines and communities, fed us, guided us and grounded us. We are intrinsically connected to our big blue backyard – more than 85% of us live within 50km of the shoreline. For tens of thousands of years, people have lived in harmony with the ocean and the wildlife within it, caring for and being sustained by its rich waters. Australia’s waters are some of the most unique and abundant places on Earth but our Marine Parks Network is falling short to properly protect them.
Australia’s marine parks aren’t living up to their name
The Australian Commonwealth Marine Parks Network covers commonwealth waters 5.5km from the coast. The network is divided into 7 regional management areas, overall the network contains 60 marine parks. Zoning types determine what activities are allowed in each area. Over half of the network allows industrial activities, risking our most precious and threatened ocean wildlife.
Within many of our marine parks, destructive industries are allowed to fish, trawl, dig and mine using barbaric and cruel methods. Here are some of the zones explained:
- Bottom Trawling: Special Purpose (trawl) zones allow bottom trawling. This covers 10 marine parks totalling almost 13 million hectares. Bottom trawlers bulldoze the seafloor with weighted nets, deforesting our underwater forests; a cruel, indiscriminate and inefficient way to fish.
- Other Industrial Fishing: Includes “Habitat Protection Zones, ““Multi Use Zones” and “Special Purpose Zones.” Fishing methods vary from park to park but many marine parks in these zones allow industrial fishing like longlining. Longlining involves setting lines that can be 100km long, bristling with deadly hooks designed to catch a specific fish species. But longlining is not a selective method of fishing – significant numbers of sharks, rays, turtles, dolphins and seabirds can be harmed or killed as bycatch in the process.
- Oil and Gas Mining: Many “Special Purpose” and “Multi Use” zones allow seismic blasting and oil and gas mining. 30 marine parks or 65 million hectares of Australia’s highest conservation value areas for ocean wildlife are open for mining and exploration of oil and gas.
- Ocean Sanctuaries: National Park and Sanctuary zones are fully and highly protected marine parks designed to conserve wildlife and their habitat, where fishing, mining, and other industrial activities are not allowed.
Industrial fishing is one of the biggest threats to the ocean
In May, Greenpeace Australia Pacific sailed our campaigning vessel Oceania through some of Australia’s most beautiful and threatened marine parks. Our crew visited Jervis and Hunter marine parks to document their beauty, showcase what’s at risk and aim to expose the industrial fishing activities in these protected waters. Both of these marine parks allow bottom trawling and longlining methods of industrial fishing.
Industrial fishing is ripping the ocean apart across the planet. Longlining, also known as longline fishing, is an industrial fishing method that involves the use of a fishing line with thousands of baited hooks. These fishing lines can stretch over 100 kilometers in length and are set to capture a fish species, often tuna or billfish species. But it is not a selective method of fishing and often results in significant bycatch. This includes a range of non-target species like sharks, rays, sea turtles, marine mammals, and seabirds which are often injured or killed as bycatch.
Bottom trawling involves dragging heavy weighted nets along the ocean floor. This fishing method is popular with commercial fishing companies, because it makes it easy to catch large quantities of fish in one go. But it also damages the seafloor, releasing carbon and can kill or injure non-target ocean life like coral, fur seals, dolphins and seabirds. You may have watched the reality of bottom trawling (and the benefits of ocean sanctuaries) in Ocean with David Attenborough, if not, add it to your watch list!
Fully protected ocean sanctuaries that ban industrial fishing and mining can protect ocean wildlife and underwater wonderlands for generations to come. Vast, robust sanctuaries create blue havens where ocean wildlife are safe from nets and hooks, and can truly rest, recover, thrive and replenish out into the surrounding waters. Ocean sanctuaries ensure a healthy ocean full of life.
A once-in-a-decade chance to fix what’s falling short
We have a unique opportunity to turn the tide.
The Australian Government is asking for your feedback on how our Commonwealth Marine Parks Network is managed. This is our once-in-a-decade chance to protect ocean wildlife, ban industrial fishing and create more ocean sanctuaries.
As part of the review the Government is asking for submissions from the public to hear from you on what improvements are needed to better protect our vast network of marine parks. Writing a submission is a powerful way to influence government decisions and create real change.
This is the moment to ban industrial activities like bottom trawling and oil and gas mining. But only if they hear from YOU. Add your name!
Greenpeace is calling on the Australian government to:
1. Ban industrial activities from Australia’s Marine Parks Network: Ban industrial activities, such as industrial fishing, seismic blasting and oil and gas mining, from Australia’s marine parks.
2. Create more ocean sanctuaries: Increase fully protected sanctuaries in Australia’s marine parks based on science principles.
3. Connect Australia’s Marine Parks Network to the High Seas: mCreate seascape connectivity by linking Australian marine parks to new high seas ocean sanctuaries.
References
Substantiation that more than half of the Marine Parks Network permits industrial activity comes from a peer-reviewed systematic literature review (Phillips et al. 2025, PLOS One, https://doi.org/10.1371/journal.pone.0307324). The study found that within the Commonwealth Marine Parks Network specifically, “all zones are considered partially protected areas, meaning areas where extractive activities are permitted, except ‘Pink zones’ (Preservation Zones; IUCN Ia) and ‘Green Zones’ (IUCN II).” In other words, every Commonwealth marine park zone type other than the network’s strict no-take sanctuary and national park zones (IUCN Ia and II) permits some form of extractive industrial activity. Since no-take zones are the minority zone type across the network by area, this supports the conclusion that the majority of the network’s area is zoned to permit industrial activity.
DCCEEW Australian Marine Parks spatial dataset (https://fed.dcceew.gov.au/datasets/erin::australian-marine-parks/explore), filtered by zone type. This confirms that 38.43% of the network’s area is zoned as Sanctuary or National Park zones (IUCN Ia and II). These are the no-take categories excluded from the peer-reviewed study’s definition of partially protected/industrial-permitting zones. The remaining 61.57% of the network falls within the zone categories the study classifies as permitting industrial activity (per The MPA Guide definition of “industrial” applied in Phillips et al. 2025), directly corroborating the peer-reviewed finding with current Commonwealth-specific spatial data.
For further information on activities permitted within the Marine Parks Network Zoning, you can refer to the Management Plans zoning and rules for each Marine Parks Network area, for example: Temperate East, Coral Sea, North.
A new report from Greenpeace Australia Pacific advocates for the closure of bottom trawling in Australia’s Commonwealth Marine Parks Network. Bottom trawling continues to be a pervasive threat to ocean life in Australia, with 10 marine parks totalling almost 13 million hectares, allowing bottom trawling.
Australia’s network of marine parks, which is the biggest in the world, covers more than half (52%) of Australia’s Commonwealth domestic waters, but not all parks are created equal. Australia’s Marine Parks Network is divided into different zoning categories, with each zone determining which activities are permitted and the level of protection provided. More than half of the Marine Parks Network allow industrial activities like industrial fishing and oil and gas mining. This includes zoning types that allow destructive fishing by longliners and bottom trawlers, who pillage underwater wonderlands, rip up coral and indiscriminately and violently catch any animal in their path, including turtles, seals and dolphins, all within areas labelled a marine park.
The Federal government has commenced a review into the majority of Australia’s Commonwealth Marine Parks Network management plans. This presents an opportunity to ban industrial activities from our marine parks and create more ocean sanctuaries.
© Harriet Spark / Grumpy Turtle Film / Greenpeace
The banner drop is a distinctive part of the Greenpeace repertoire.
The moment of the unfolding is intrinsically dramatic. It is the reveal; when the moral and scientific truth of a situation is unveiled to the world. The wrong is being labelled—not through a written submission, or a social media post, or a statement in a meeting—but in words emblazoned in real physical space, chosen and occupied with precision, for all to see. There is jeopardy and transgression. And there are consequences—for the activists and for Greenpeace, as well as for the target of the communication. One of the reasons the banner remains such an effective tool in our toolbox is because of its undeniable clarity in cutting through, driving change and accountability in a way that few other tactics can. It is naming the wrong: in giant, clear letters.
We’ve hung these massive messages at environmental crime scenes, corporate headquarters, and iconic landmarks; on government buildings, ships and planes—in locations all around the world, for years.
My own memories unfurl even as I write this, but because the campaign to stop Woodside at Scott Reef is so pressing, what immediately springs to mind are two of our banners in that campaign: one on a crane outside their Perth HQ, and another on some of their corroding industrial junk at sea. What about you? Is there a particular banner that you picture when you think of Greenpeace?
The banners can attract global attention, but they have quiet beginnings. Each one is made by hand, often by volunteers. It is the invisible labour behind each spectacular public moment. One of the key pieces of equipment in our workshop at Rainbow Warrior House is the sewing machine. Sometimes our workshop is full of people and noise; at others it is quiet, the only sound being the gentle, purposeful, whir and buzz of a banner being sewn. It is usually our warehouse manager, Kieran Holmes, on the tools, head over the machine, carefully pouring over the raw canvas or tarp as the banner takes shape. Kieran’s one of those people who seems to be able to turn his hand to almost anything, but you wouldn’t know it because he’s old-school modest. In addition to being incredibly skilled, Kieran’s an all-round beaut human to have in the heart of our headquarters; never too busy to take the time to show a newcomer, or curious visitor, around his domain.
Once the banner is sewn up, the lettering needs to be outlined. This is done on a magnetic wall—a fit-for-purpose feature at Rainbow Warrior House, where the banner is held up with magnets, and the edges of the letters neatly traced from a projection.
Next comes the painting. It usually starts late in the afternoon, sometimes going into evenings and weekends, with volunteers, staff, mates crowded around, brushes in hand. It is a calming meditative feeling of shared purpose, giving each letter its visual heft, the colour building power and presence with each stroke.
Then you stand back, stretch, and look at the message, now ready.
S A V E S C O T T R E E F
Throughout history, every great push for social change has required some form of invisible labour; preparation in the form of quiet things seldom seen, but vital. It is the enabling work of love instantiated in action. And of course, so much of the time it has been women who have done this labour, so that the men could get the chance to make the speeches and stand on the podiums. The inaugural Greenpeace voyage to stop nuclear testing in 1971 had a male-only crew, but wouldn’t have happened without the ideas and work of women behind the scenes.
It is what we do together, after all, that changes the world. Sometimes that work happens on a stage, a ship on the wild seas, or up the side of a building. But mostly, it is the hidden diligence of those who care and contribute to all the enabling work that makes a change once thought impossible, inevitable. It is Kieran at his sewing machine. It was Dorothy Stowe doing the administrative work of the ‘Don’t Make A Wave Committee’ that became Greenpeace.
When we think of social change, it is the sturm and drang that we remember. The drop of the banner, the chant of the crowd, the raising of the new flag. But look behind the curtain, and there’ll be a crew of people who are taking responsibility for the administration, the sewing and the painting, making the food, checking the bus timetables, getting stuff done. And behind them are even more handsinvisibly donating time and trust; the financial, material and expert resources that make it all possible. There’s love, camaraderie and know-how at every stage.
We are social and cooperative creatures by nature. And we human beings have been stitching for millenia, sewing the possibilities of our common future. Political and corporate bullies and algorithmically manipulative platforms would have us forget this, and abandon who we are. But we should be in no doubt that the brighter prospects for ourselves and life on earth continue to be stitched and painted; collaboratively and with love, by the diligent hands of millions of people who care, each day, in every community and city across the world.
With Love,
David
Q & A
I always get great questions when interviewing prospective new team members. One that came up again recently was: “Is Greenpeace actually one organisation?”
Around the world, people know Greenpeace by our one global name, united by a shared mission: securing an Earth capable of nurturing life in all its magnificent diversity, with a particular focus on climate and biodiversity. Behind the scenes, though, we’re organised as a network of 25 legally autonomous national and regional offices, including Greenpeace Australia Pacific, working alongside Greenpeace International.
That structure gives us the best of both worlds: we work together leveraging the power of a global network on the issues that matter most, while each office remains legally independent and deeply connected to the communities, cultures and political realities where we’re embedded. Local knowledge informs global action, and global collaboration strengthens and supports local campaigns.
It’s a model that has enabled Greenpeace to take on some of the world’s biggest challenges for over five decades–while withstanding challenges and attacks from governments and corporations. Global enough to tackle global problems, local enough to understand our communities and the natural places we love.
If you’re curious to learn more, you can read about the Greenpeace Global Network structure here.
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