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The Trump administration wants to roll back some Biden-era restrictions on smog-causing emissions from heavy-duty vehicles.

Recent technological advances have brought the president’s goals a bit closer to reality.

Britain expands heat alerts while estimates suggest June’s death toll could surpass 20,000 across continent

The UK is sweltering through the peak of its third heatwave of the year as countries around Europe struggle to recover from an early onslaught of baking summer heat.

Punishing temperatures pushed higher by fossil fuel pollution have broken records across the continent in recent weeks. Western Europe experienced its hottest June on record, scientists confirmed on Thursday, accompanied by high global ocean temperatures that could cause “mass-mortality events” for some species.

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Exclusive: ‘The preferred policy is, of course, a carbon price,’ Dr Huw McKay says, amid slowdown in BHP action on emissions

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A former chief economist at mining company BHP says stronger climate policy by governments is needed to “move the needle” and incentivise tough decarbonisation decisions at major resource companies.

Internal documents, leaked to Guardian Australia and the ABC earlier this year, showed BHP had delayed vast renewables projects in the Pilbara, scrapped a project that would have delivered significant cuts to global emissions, and war-gamed options to push the electrification of its polluting diesel truck and train fleets into the next two decades.

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Most cases used to be seen after exertion or being left in cars, but extreme heat has widened risk

Extreme temperatures are causing heatstroke in pets even when they are restricted to homes and gardens, vets have warned, as parts of the UK enter the third heatwave of the year.

Temperatures have reached 40C or more in recent weeks in countries including Germany, France and Spain, with western Europe experiencing its hottest June on record. While such events have been linked to hundreds of excess deaths in people, the rising mercury is also taking its toll on animals.

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In yet another year defined by record breaking weather events, attribution science can play an important role in articulating how climate change is both contributing to and worsening extremes. 

In broad strokes, attribution science identifies and quantifies human contributions to climate change and its related impacts. Attribution research has provided foundational understanding about climate change for over 30 years and has been a cornerstone of the United Nations’ Intergovernmental Panel on Climate Change (IPCC) assessments, which serve as the global authority on consensus climate change science. These studies are retrospective and distinct from climate impact time series because they isolate the role of climate change and address questions of causation. Similarly, they are separate from projection studies that model the impacts of climate change into the future. 

Attribution science includes four interrelated subfields—trend, source, impact, and extreme event—which provide different kinds of insight into the consequences of climate change. This blog, however, will focus specifically on what extreme event attribution can tell us about our world and discuss strategies to communicate both its findings and its limitations.

A brief history of extreme event attribution

Did climate change make this heatwave more likely?

Did climate change make this downpour more intense?

Extreme event attribution (EEA) answers research questions like these. Like so many scientific disciplines, attribution research has evolved over time, allowing scientists to answer new questions about the impacts of fossil-fueled climate change.

The first EEA study focused on a devastating heatwave that occurred in Europe in 2003, that led to 35,000 excess deaths and the creation of extreme heat warning programs in countries across Europe. The study, published by Peter Stott and colleagues in 2004, found that human influence had more than doubled the likelihood of this event. While attribution methods had previously shown how climate change had contributed to trends like rising global average surface temperatures, this study represented a huge methodological advance by isolating the role of climate change in an individual event for the first time.

Over the past 20+ years, the field has evolved rapidly, increasing our understanding of how climate change is driving extreme weather. This type of research has shown that during Hurricane Harvey, climate change tripled the likelihood of extreme rainfall and increased total rainfall by at least 19%, with a best estimate of 37%. Similarly, research on extreme heat has shown that climate change made the 2021 Pacific Northwest heatwave up to 3.6°F hotter.  

Sometimes this research finds that climate change did not play a role in a given extreme event. A study focused on May 2023 extreme rain in northern Italy, for instance, found that climate change didn’t affect the event’s likelihood or severity. Results like these affirm the rigor of this methodology, but are also rare given the fundamental changes to our atmosphere.

EEA studies have also become critical evidence in IPCC assessment reports, supporting key findings like:

“Human-caused climate change is already affecting many weather and climate extremes in every region across the globe” and “It is virtually certain that hot extremes (including heatwaves) have become more frequent and more intense across most land regions since the 1950s, with high confidence that human-induced climate change is the main driver of these changes.”

Each statement and figure included in the Summary for Policymakers section of IPCC reports (like those quoted above) are approved by every country that participates in the IPCC in collaboration with the report’s scientific authors. As a result, the inclusion of EEA research in IPCC reports and the Summaries for Policymakers underscores the robust methodology that underlies these studies as well as their role in shaping the consensus understanding of climate change.   

Innovative studies moved the field of EEA forward in 2025, with two high profile studies that addressed research questions about the contributions of emissions from the Carbon Majors, the largest fossil fuel producers and cement manufacturers in the world, to extreme heatwaves.

One study attributed the economic costs of several extreme heatwaves to the emissions of the Carbon Majors, finding that the emissions of single emitter, Chevron, have led to between $791 billion to $3.6 trillion USD in heat related losses over a 31 year period.

Another study systematically attributed 231 heatwaves to emissions from the Carbon Majors, finding that their emissions contributed to half of the increase in heatwave intensity over the last 120 years, and that between 16 and 53 of these heatwaves would not have occurred without emissions traced to these entities. Like the Stott study in 2004, these studies highlight major developments in extreme event attribution and foreshadow the exciting research on the horizon.

Ease of attributing the role of climate change depends on event type and geography

Extreme event attribution research builds on decades of peer-reviewed science. The available data and methodology, however, mean that scientists can attribute some types of events with higher confidence and that the geographic spread of these studies skews heavily towards events in the Global North.

The events that can be attributed with the most confidence are those that are most closely tied to temperature increases, like heatwaves. Isolating the contribution of climate change can be more complicated for more complex events,  like convective storms that involve more complex processes. This translates to different levels of confidence in the attribution of certain types of events, which is reflected in the published literature about these topics. The IPCC is very clear about this while also affirming the confidence and rigor of studies and event types where scientists have stronger confidence in their conclusions.

Extreme event attribution research is also not well distributed geographically, with lots of studies focused on events in the Global North and far fewer studies on events in the Global South. Systemic issues can make bridging this gap difficult. For example, long term data sets required to establish a baseline in this type of research are often more readily available the Global North, which carries important equity implications as attribution science becomes important in the accountability and litigation spaces.

EEA research is one important tool among many for understanding climate change. However, remaining cognizant of its limitations and working to overcome them will be key as the field continues to develop.

Communicating about climate change and extreme events

Attribution science is a broad field of research, but EEA research has become its poster child, in part, due to the work of World Weather Attribution which conducts rapid attribution studies using peer reviewed methods, often resulting in broad media coverage. While these studies have increased awareness of fossil fueled extreme events, they have also led to confusion about what types of questions attribution science can and can’t answer. answer.

Attribution science answers questions like: did climate change make this event more frequent or intense?

It does not answer the question: was climate change the sole contributor to this event?  

Similarly, we’re never going to have an attribution study for every event. But even without one, climate science—particularly trend attribution research—can inform our thinking about how climate change may have played a role.

For example, hurricanes are super complex events, and tropical cyclone formation is notoriously hard to model. As a result, I’m not aware of any EEA studies that demonstrate how climate change contributed to the formation of a specific hurricane. As discussed above, much research has established the connection between climate change extreme precipitation associated with hurricanes.

However, we also have robust trend attribution research that shows the key role of climate change in rising sea surface temperatures, which can allow storms to rapidly intensify. Similarly, sea level rise attributed to climate change can exacerbate flooding from hurricanes. When talking about hurricanes in the absence of an EEA study, highlighting these key pieces of information is key in contextualizing how climate change may be contributing to these events. This distinction matters because scientific integrity requires us to be clear about what we know and what we don’t. We can state with confidence that climate change is warming oceans and raising sea levels (both of which worsen hurricane impacts) while acknowledging that other aspects remain less certain. Being precise about this strengthens, rather than weakens, the science.

Wildfires represent another example of this. As individual events, they are incredibly difficult to attribute to climate change due to the range of factors that play a role like historical banning of cultural burning practices by Indigenous communities, forest management, and ignition source. But we have amazing trend attribution science that can allow us to say a lot about the role of climate change in these events. A 2016 study, for example, showed that climate change via increased dryness nearly doubled burned area in forests of western North America between 1986 and 2015. This study looked at many wildfires in aggregate to understand the role of climate change.

Following the devastating January 2025 wildfires in Los Angeles, one rapid attribution study found that climate change made the observed extreme fire weather—that drove the rapid spread of wildfires in the region—35% more likely. Together, this research shows that while event attribution studies allow us to quantify the specific contribution of climate change to a given event, we have a wide range of other science we can rely on to show how climate change is impacting our communities and ecosystems.

Moving forward: Five things to keep in mind when talking about attribution science

As attribution science continues to grow and find new applications—from IPCC assessments to courtroom evidence to help with city planning—how we talk about it matters. Here are key considerations for communicating about EEA and attribution science more broadly:

1. Be precise about the questions EEA can answer. Extreme event attribution tells us how climate change influenced an event’s likelihood or intensity, not whether climate change was the sole driver of an event. This distinction matters when framing EEA as answering “did climate change make this more likely or severe?” rather than “did climate change cause this?” and avoids overclaiming while still conveying meaningful information about climate change’s role.

2. Acknowledge varying confidence levels without undermining the science Confidence in attribution findings varies by event type. Heatwaves, which tie closely to temperature increases, can be attributed with high confidence. More complex events like extreme precipitation or hurricanes involve additional factors that complicate isolation of climate change’s contribution. Attribution science still has a lot to say about most event types, but communicating these differences transparently strengthens credibility while still affirming the robust methodology underlying the research. These methodological constraints represent opportunities for the research to further develop.

3. Absence of an attribution study doesn’t mean absence of a climate connection. Not every event will have a dedicated attribution study, and that’s okay. Trend attribution research can inform our understanding even when event-specific studies don’t exist. For hurricane formation and intensification, for example, we can point to robust science on rising sea surface temperatures and sea level rise to contextualize climate change’s role without needing a specific EEA study for each storm.

4. Extreme event attribution exists within the broader attribution science research field. Extreme event attribution is one of four interrelated subfields,alongside trend, source, and impact attribution. Communicating EEA as part of this broader toolkit helps highlight that multiple lines of evidence can inform conclusions about climate change’s contributions, even when one type of study isn’t available.

5. Attribution science is robust and continues to evolve. From the first 2004 European heatwave study to 2025 Carbon Majors research attributing economic costs and heatwave occurrence to specific emitters, EEA has rapidly expanded the questions it can answer. Pointing to these advances signals that attribution science is dynamic and continues to develop new tools for understanding climate impacts.

Attribution science has come a long way in two decades and continues to develop. By communicating its findings and its boundaries clearly and constructively, we can help ensure this research continues to inform the decisions, policies, and accountability efforts that shape our climate future.

Temperatures across ravaged region 3C above average as scientists warn of risks for people, ecosystems and infrastructure

• Record wildfires in Europe show failure to adapt carries a mounting cost

Western Europe has been scorched by its hottest June on record, scientists have said, as the UK enters its third heatwave of the year and wildfires ravage France and Spain.

Inflamed by carbon pollution, the deadly June heatwave helped push surface air temperatures for the region 3.06C above their average from recent decades, according to the EU’s Copernicus climate monitoring service.

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An unusually early heat wave smashed records across France, Britain and Spain. Temperatures in some areas are starting to soar again.

Our July 4 bash was troubled, and America may go the way of the Ghaznavid Empire. But here are reasons to be more positive.

Scientists are increasingly able to determine how human-caused emissions have increased the risks of particular events and the harms they produce—advances that are critical as communities experience ever more costly and dangerous extreme weather. This work is known as attribution science: a robust and growing field that examines the role fossil-fueled climate change plays in specific weather events, long-term climate trends, and their real-world consequences.

As my colleague Dr. Delta Merner explains, attribution science includes several connected areas of research. The first, “event attribution,” asks whether climate change made a particular weather event more likely or more intense. The second, “source attribution,” traces climate change and associated hazards back to emissions sources or sectors. And third, “impact attribution” examines the resulting harms, including damage to homes and infrastructure, lost livelihoods, health impacts, and deaths.

Attribution science utilizes a suite of tools to understand these connections: earth observations, statistical methods, emissions data, and climate models. Climate models are a central tool of attribution science through their ability to develop modeled counterfactuals—that is, simulations of what our world might have been without human-induced warming.

Climate models and attribution science have both advanced rapidly over recent decades, making both critical tools for understanding how climate change is progressing and fossil fuel companies’ responsibility for its worsening effects.

So, how exactly are climate models used in attribution science, and why can we have confidence in the conclusions they help produce?

What is a climate model, and why does it matter for attribution?

Climate models are among the main tools scientists use to simulate how Earth will respond to increasing concentrations of heat-trapping pollutants in the atmosphere. When scientists refer to climate models, they generally talk about a general circulation model, or GCM. These models simulate how the atmosphere, oceans, land, and cryosphere respond to changes in internal climate dynamics, such as the El Niño-Southern Oscillation (ENSO) and Atlantic Multidecadal Oscillation, and external drivers, including greenhouse gas emissions.

Climate models are some of the most reliable tools for understanding our earth-climate system because they have been improved, tested, and updated for decades. 

Modern climate models are made up of connected component models for the atmosphere, ocean, land surface, and cryosphere. An atmospheric model, for example, simulates circulation, radiation, clouds, and aerosols. Ocean models simulate circulation and heat uptake. Land models represent processes such as soil moisture, vegetation, snow cover, evapotranspiration, and carbon storage.

When these components are connected, or coupled, they exchange information with one another, allowing models to represent the feedbacks and interactions that shape the real-world climate system. These coupled models are often compared through coordinated international efforts such as the Coupled Model Intercomparison Project, or CMIP, which allows scientists to evaluate results across many models, institutions, and experimental designs.

CMIP simulations are also a major source of evidence for national and international climate assessments, including reports from the Intergovernmental Panel on Climate Change (IPCC), where they help scientists assess past climate change, project future risks, and evaluate confidence across different concentration scenarios and model results.

At their core, climate models use well-established physical laws to calculate how energy, momentum, water, and other properties move through the climate system. They divide the planet into a three-dimensional grid and calculate how conditions such as temperature, moisture, winds, and rainfall change over time and from place to place.

Attribution science: Comparing what is with what could’ve been

For attribution science, knowing how each of these factors contributes to our climate matters enormously. Event attribution compares the climate in which an event occurred (usually today’s climate) with a counterfactual climate that is identical except for the added influence of human-caused warming. By running climate model simulations with—and without—observed human influences, researchers can quantify how greenhouse gas emissions changed the probability or intensity of an event.

For example, a heatwave may have occurred because of a particular weather pattern, but human-caused warming can raise the baseline temperature on which that weather pattern acts, making an extreme heat event more likely, hotter, longer lasting, or all three. The 2021 Pacific Northwest heatwave illustrates this clearly: the region has already warmed by 1°-1.5°C, and event-specific attribution studies found that the heatwave would have been virtually impossible without human-caused climate change and was about 1°C hotter because of it. The relevant question is therefore how much climate change shifted the odds, intensity, or consequences of any given event.  

Climate models have a strong track record for simulating global warming

Climate models are some of the most reliable tools for understanding our earth-climate system because they have been improved, tested, and updated for decades. Their development spans generations of scientists and computational advances, and they continue to improve.

In fact, a recent study found that climate models that were developed over 50 years ago have correctly predicted the Earth’s warming. The fact that models developed decades ago broadly projected the warming trajectory we are now living through is strong evidence that they capture the core physics of global warming.

Furthermore, climate models have evolved in both scale and resolution, improving our ability to understand regional and localized changes to our earth-system. While global climate models are essential for understanding large-scale warming and circulation patterns, regional models can provide more detailed information about how those changes interact with local geography, land surfaces, coastlines, mountains, cities, and weather systems. This is especially useful when studying events such as convective storms, storm surge, flooding, and wildfires, where local and regional processes can strongly influence the severity of an event.

The advances by climate models and their proven record for simulating our earth system are important in the attribution of science. Climate models allow scientists to translate that physical understanding into quantitative estimates of how human-caused warming has changed the likelihood, intensity, or impacts of specific weather extremes.

Climate models address scientific uncertainty

Attribution scientists use multiple robust methods to test, constrain, and quantify uncertainty. One of the most important methods is the use of climate-model ensembles, which help scientists distinguish the role of natural variability from the influence of human-caused warming when assessing extreme weather events and their impacts.

First, scientists use initial-condition ensembles to understand internal climate variability. In these experiments, researchers run the same climate model many times with nearly identical conditions, changing only very small differences in the initial state of the atmosphere or ocean. Because the climate system is complex and chaotic, these tiny differences can lead to different weather patterns and different sequences of natural variability over time.

This allows attribution scientists to simulate the range of outcomes that could occur under the same external conditions. When researchers compare a world with human-caused emissions to a counterfactual world without them across many simulations for each scenario, they can see whether the climate-change signal consistently shifts the likelihood or severity of an event beyond the range expected from natural variability alone.

Second, scientists use multi-model ensembles to evaluate structural uncertainty, which originates in the scientific choices made by developers of each model. Different modeling centers make different scientific and technical choices about numerical schemes, parameterizations, spatial resolution, and how to represent processes such as clouds, aerosols, land-atmosphere interactions, and ocean circulation because the climate system is complex and no single model can perfectly capture every process at every scale. Comparing results across models helps scientists determine whether a finding is robust across multiple plausible representations of the climate system.

That said, some models can be similar in their representation of certain interactions in the climate system, mainly due to the fact that a few were developed using the same computer code and parameterizations. Regardless of the choice, researchers use methods that account for both model performance and model interdependence, giving less weight to structurally similar models or models that perform less well against observations.

The purpose of ensembles is to understand and constrain uncertainty in a transparent way. And what is clear is that, with both types of ensembles, there is greater confidence in the climate-change signals on a variety of weather extremes and impacts.

Bottom line: Climate models are important tools for attribution science

Climate models are essential tools for attribution science because they are grounded in well-established physics, tested against observations, and used alongside multiple lines of evidence. Attribution science brings together physical understanding, observations, statistical analysis, emissions data, and climate-model experiments to test how human-caused warming is changing the risks people face today. The use of multiple datasets, models and methods is what makes the field robust, allowing scientists to compare the world as it exists now to a counterfactual world without human-caused warming, quantify uncertainty, and assess how much climate change has shifted the likelihood, intensity, or impacts of specific events.

Higher sea temperatures have followed scorching weather across Europe, prompting Britain’s weather service to declare a “severe” marine heat wave.

Hotter temperatures and harsher droughts could cause Indigenous societies to lose many of the species they have used for medicine, rituals and more, scientists found.

They suck up energy and water, and blast out heat. Just who is better off from all this investment – aside from tech bros?

The two great existential threats of our time – the climate crisis and AI – come hurtling together in the explosion of datacentres across Australia and around the world.

You can hardly avoid hearing about them these days, either with awed reverence of the promised benefits to humankind or with fear and anger given the implications for the climate, inflation, jobs and even housing affordability.

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Experts warn that some marine species are at risk of ‘mass mortality events’ in ever-warming oceans

UK waters are being hit with an “extreme” marine heatwave, the Met Office has said, as scientists warn that high ocean temperatures globally could result in “mass-mortality events” for some species.

The forecasters said these elevated temperatures have developed rapidly because of last month’s heat dome, during which most of Europe sweltered in its worst ever heatwave that scientists said would have been impossible without the climate crisis.

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Climate crisis prompts calls for workplace temperature limits and rights to heat breaks and adjusted working hours

As Europe’s sweltering summer continues, trades unions are mounting a push for new laws to counter deadly heat stress that is linked to an estimated 230 workplace deaths a year.

This year’s toll may be even higher, with 1,300 excess European deaths already connected to the June heatwave by the World Health Organization, and other estimates running as high as 20,000.

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Estonia, Luxembourg and UK are the top three in biennial Yale University index in tackling pollution and other issues

Much of the world has made encouraging strides in reducing toxic problems such as water and air pollution that have long plagued communities. But there is still a widespread lack of progress among countries in dealing with the climate crisis, according to the latest edition of an influential environmental scorecard.

The biennial Yale University index again ranks Estonia as the best-performing of 177 assessed countries, after strong recent efforts to reduce its greenhouse gas emissions and protect its ecosystems. Luxembourg is second, and the UK is third, having moved up from fifth place in the 2024 index.

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