Extreme weather is becoming more destructive as the world warms, but how can we say that climate change intensified the fires in Los Angeles, typhoons in the Philippines, or flooding in Spain?
That question was once difficult question to answer. But thanks to the pioneering field of attribution science, experts can quickly examine the possible influence of global warming on a specific weather event.
The fast-growing field began two decades ago and is now firmly established, but it is still sometimes hampered by a lack of data.
Real-world impact
After disaster strikes, an attribution study can quickly help tell governments, industry and ordinary people if climate change played a role.
"It's important for citizens, for decision-makers, and it's also very important for scientists, because with each case study, we learn new things about our models, our observations and the problems we encounter with them," said Robert Vautard, a leading scientist with the U.N.'s climate expert panel, who has supported the development of attribution studies.
In the future, these studies could also play a growing role in legal disputes.
Already a 2021 scientific study was used by a Peruvian farmer in his battle against German electricity giant RWE, which he accused of playing a role in the melting of a glacier.
That research found the glacier's retreat was "entirely attributable" to global warming.
Different approaches
The main questions attribution studies seek to answer are: did the warmer climate make a flood, heatwave, fire or storm more likely, and did it increase its ferocity?
Several groups have developed methods that have been independently validated by other researchers.
The most active and influential group of researchers is World Weather Attribution (WWA), whose work is often reported in the media.
Using computer models, scientists can compare a simulation of a particular weather event against a world in which warming caused by the burning of fossil fuels and other human activities was not present.
In their most recent study, WWA researchers found that climate change increased the risk of the Los Angeles wildfires, which have killed at least 29 people and destroyed more than 10,000 homes since igniting on January 7.
Tinderbox conditions fuelling the blazes were approximately 35 percent more likely due to global warming caused by burning fossil fuels, they found, reducing rainfall, drying out vegetation and extending the overlap between flammable drought conditions and powerful Santa Ana winds.
Other organisations running attribution studies include Britain's Met Office, which also compares today's climate with simulations of a world with a climate more like the one before the Industrial Revolution.
Yet others use more broad-brush techniques, including ClimaMeter, which describes itself as "an experimental rapid framework for understanding extreme weather events".
The group uses historical observational data, rather than more complex computer models, as well as news reports and AI tools like ChatGPT, although it admits that its method is less effective at analyzing very unusual events.
No single cause
Scientists stress that climate change should not be considered the sole cause of an extreme event and its impacts.
"For instance, if a heavy smoker develops lung cancer, we would not say the cigarettes caused the cancer -- but we might say the damage caused by the cigarettes made it more likely," WWA explains on its website.
Researchers also look at political or social factors that make a weather disaster more deadly or destructive -- poor quality construction, for example, or badly maintained infrastructure.
Some types of extremes have a well-established link with climate change, such as heatwaves or heavy rainfall.
"More and more, we're starting to have events that we can clearly say would have had a near-zero probability without our influence on the climate," said Sonia Seneviratne, a climate scientist who has worked with WWA.
"Events are now becoming so extreme that it's easier to detect this influence," she notes.
Other phenomena like droughts, snowstorms, tropical storms and forest fires can result from a combination of factors and are more complex.
Search for data
Another limitation that worries researchers is the scarcity of observational data and measurements in certain parts of the world, particularly in Africa.
That dearth makes it harder to study impacts, leading to inconsistency between different analyses.
"The lack of observed data is penalising in certain regions. There is also a lack of model data, i.e. high-resolution climate simulations," said Aurelien Ribes, a climate scientist at the French meteorological research agency CNRM.
He stressed the need for consistency and said that "any future use of this data in legal or compensation proceedings will have to be based on more systematic approaches".
© 2025 AFP
24 Comments
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iknowall
The California fires easily could have been prevented with proper forestry control.
Desert Tortoise
This statement right here is the crux of the problem. There was no forest where the fires burned. I grew up very close to where the fires burned and know that terrain well from hiking and biking it. The vegetation is dry grass, scrub oak and chaparral. You have to get much higher up in the mountains, a thousand meters more altitude to start seeing anything that resembles a forest, and even that is pretty sparse. The trees are short and far apart because the region is arid.
What you saw was the result of there having been no rain is around 300 days. December was dry, which is very unusual. January was dry until a few days ago. You also had winds gusting to 160 kmh. From experience living there when you have any kind of fire driven by winds like that all you can do is get out of the way. Aircraft cannot fly in such winds. LA County Fire indeed tried and almost lost a helicopter caught in a down draft as the winds tumble off mountain peaks at high velocity. One helicopter reported showing an airspeed of 80 knots while at the same time they observed their helicopter was moving backwards over the ground. You can't drop water in conditions like that.
The vegetation that burned has to burn to regrow. The seeds those plants deposit lay dormant under ground until the heat from a fire causes them to germinate. This is how the chaparral regenerates itself. However the new plants need 5-6 years of growth before they begin to drop seeds. If you burn them off too early there are no seeds in the ground to germinate and regenerate the chaparral. A problem the region faces is that non native grasses grow very quickly on the burned out areas. These grasses dry out quickly and fuel new fires. But remember the new growth chaparral needs 5-6 years before they drop new seeds. Non native grasses and their frequent fires are killing off the chaparral and increasing the fire danger.
But again, this is not a matter for "forestry control" There is no forest. And obtw, fully half the forested land in California are on Federal lands where Federal laws and forest management applies. The state of California has no authority to do anything on Federal lands. The state and local fire departments cannot even legally enter a National Forest to fight a fire in one unless they are invited to do so by the Federal Government. Some years back after the USFS let a fire in Angeles National Forest get away from them and burn a thousand homes after telling LA City and County Fire helicopters to stand down ( ! ) both LA City and County threatened to ignore the Federal authorities and fight fires in the national forest anyway. That has not happened and since them agencies cooperate better. That fire was also the seed that led to all the helicopters using night vision goggles and fighting fires at night. Previously on LA County Fire helicopter pilots used NVGs and flew into fires at night. LA City Fire would occasionally also fly at night but they didn't have NVGs and relied on the Mk-1/Mod-0 eyeball.
iknowall
False.
Forestry does not just mean "forest". As you wrote, there was scrub oak, which is a tree, which is part of forestry. In addition to other trees, and dried grasses and vegetation, which was not controlled. Times changed in the area from where you grew up 50 years ago.
This point is not disputed as to what made the fires so extreme. Trump had been warning NEwsom for 8 years about the risks of not controlling the forestry, and we saw the result.
TaiwanIsNotChina
Even more important than the shrubs was the 100 mph winds. No sense in covering for the idiocy that comes out of the Trump.
iknowall
Winds don't cause a fire. It's the burning shrubs and other tinder.
Trump is doing phenomenal as president, and shows he cares about the people.
Newsom on the other hand has been a disaster for California.
The California governor pledged in 2019 to reform California's approach to wildfire prevention, but a 2021 NPR investigation reported the governor overstated the efforts.
*"The investigation found Newsom overstated, by an astounding 690%, the number of acres treated with fuel breaks and prescribed burns in the very forestry projects he said needed to be prioritized to protect the state’s most vulnerable communities,"*
Desert Tortoise
The state has no authority on Federal lands. Angeles National Forest is federal land. The state of California controls a whopping 3% of the forested land in California. The Federal government owns over half and the rest is private property. Again, your uninformed comments make the problem worse, not better.
Again wrong. There are problems with forestry in the US but again those problems begin and end with the Federal government and their policy of clear cut logging of Federal forests. The land that burned was emphatically not forest. It is chaparral, an entirely different form of vegetation that is at most two meters tall and much drier and lower altitude than a forest in that part of the country.
You know nothing of the land I call my home. Not one thing and making blanket statements out of ignorance are what are causing the problems. The state of California with its measly 3% of the forested land in the state spends more on wild fire prevention and controlled burns than the Federal government does with over 50% of the forested land. Your argument is based on falsehoods.
iknowall
It was part of the forestry left neglected by Newsom.
This is not even an issue in dispute.
Desert Tortoise
More BS. Ever fan a camp fire with a newspaper of piece of cardboard to fan the flames and make the fire burn hotter? This is my home and where I grew up. Those winds feed the fire and drive it. Without the winds the fires are manageable. But you cannot stop a fire pushed by 100 mph ( 160 kph ) winds. The firefighting aircraft could not fly in those winds much less drop water or retardant. Example, an LA County Fire Dept helo was showing 80 knots airspeed but the crew observed the helicopter was traveling backwards over the fire. Take the winds away and you can fight a fire with air assets and get ahead of it. LA County had aircraft in the air from the beginning but had to retreat after almost losing one to a down draft.
What you also ignore is that kind of brush has to burn periodically to regrow. The seeds do not germinate unless there is a fire. Only then, after a hot fire will new chaparral sprout. But if you burn it too often the new plants do not have enough years to deposit the seeds necessary to rejuvenate themselves afterwards. Fire is necessary but it can't be too often.
None of this would be a problem if developers didn't build homes into high fire danger areas with counties and cities too often accommodating them. I grew up near these very same foothills that just burned. That is my home and I know those mountains well from hiking and biking them. They have burned over and over again. It is a normal part of the cycle of life and necessary. What isn't necessary are all those homes tucked into the canyons or on pads graded into the ridge tops. They should never have been allowed but it is too late to take it back. The fires are not going to go away. Thinking you can somehow prevent them is a fools errand. They are required for a healthy ecosystem. Get the homes and business out of the way instead.
iknowall
What started the camp fire in the first place? Wind?
Simple, elementary, basic science.
virusrex
The intensity and dispersal of the fire has been scientifically proved to be affected by climate change, that includes the wind but also the changes in precipitation.
Pretending the scientists on the field have not declared climate change as one of the factors affecting the fires reveals antiscientific bias, it is even simpler and more elementary than any science to simply listen to the experts.
Desert Tortoise
Poor maintenance of power lines by PG&E. But the arcing would not have occurred had there not been wind blowing the power lines into adjacent trees.
And who is responsible for trimming those trees? PG&E, not the state. PG&E owns the rights of way.
Desert Tortoise
The state has no authority to conduct controlled burns in Angeles National Forest or on any Federal lands. The state spends more money on controlled burns and fire prevention on their tiny 3% of the state's forests than the Federal Government spends on the roughly 50% of the states forests they own (National Parks, National Forests and BLM land). And from experience their controlled burns in the Sierra Nevada often go out of control. I have seen that happen year after year. Nonetheless the state spends more money and puts more effort into fire prevention than the Federal Government even though the Federal Government owns most of the forests in the state. Nothing the state of California can do about that. It is up to Congress to manage those forests including Angeles National Forest.
iknowall
False.
I never mentioned "controlled burns".
The State of California (i) knew these winds were coming for 20 years, (ii) neglected to maintain safely forestry. and also (iii( failed to implement laws for homeowners to keep areas near their houses clear of brush and tinder-like substances.
Newsom dropped the ball big time, as he had been warned almost 10 years ago, and instead, he and California literally were burned.
virusrex
Which would explain why your argument does not hold water, this is a well characterized measure that the federal government could have used to control the risk, but did not. Avoiding to mention this do not make the argument less valid, it just makes it clear you tried to hide it because it refutes your claims.
I'veSeenFootage
Completely obvious to anyone with a working brain. But of course after the next catastrophe MAGA fans will continue blaming DEI, the democrats, the socialists, the marxists, the immigrants, the trans...
iknowall
You don't understand the issue.
The State of California could have used controlled burns, but they did not even though Trump advised Newsom to do so almost 10 years ago.
It's not an argument unless it is an issue.
But in fact, it supports my claims even more, if you understood federal law and the responsibilities of the State of California regarding fire suppression areas.
Thank you for mentioning it!
virusrex
Proven false in many comments that you refuse to address, therefore remain valid. The federal government was the one that could have taken action, not the State of California, repeating this false claim without being able to argue how California could have acted on Federal territory do nothing to demonstrate it could have done anything, it just makes it clear this argument completely defeat your point so you are trying to ignore it instead of refuting it.
The artument remains valid, you trying to ignore it do not make the issue disappear, it just makes you unable to accept it without any rational argument to support this position.
Both refute your arguments, easy to see the moment you refuse to address the arguments and just claim (without basis) they support your misunderstanding.
Desert Tortoise
Again, for the upteenth time, there were no forests burning. It is sage, scrub oak and chaparral. Forest management doesn't apply. No trees, nothing even remotely resembling a forest.
Los Angeles County has an ordinance requiring brush clearance and other fire safety measures.
http://lacounty-ca.elaws.us/code/coor_title32_sec325.2.1
Likewise the City of Los Angeles has its own brush clearance ordinance
https://issuu.com/lafd/docs/ordinance_no_185789__mayor_signatur?e=0
You are arguing with someone who grew up and lived most of their life adjacent these very same mountains. You know nothing about them.
The state has never conducted controlled burns on Federal lands. They have no authority to do so. Federal forestry employees have conducted controlled burns on Federal lands but they have lost control of many. i live near where some of these "controlled burns" got away and became major fires.
The state only owns 3% of the forested land in California, and those are state parks. The state spends more on controlled burns and other fire prevention measures than the Federal Government does. They provide grants to cities and counties to clear brush within their jurisdictions.
iknowall
That's what I said from the beginning.
Welcome to the discussion.
Right, Except in this case Newsom refused to do so even though he was warned by Trump almost 10 years ago of the risks.
Are you purposely posting to the wrong article and the wrong discussion??
Desert Tortoise
Federal law imposes no requirements on states to conduct controlled burns. You don't even understand how our government works. In California roughly half the forested land is owned by the Federal Government. They and only they are responsible for fire safety on those lands. The states have no authority to operate or do anything on Federal land. LA County Fire cannot enter a National Forest and fight a fire there unless the US Forest Service grants them access. They are not permitted to conduct controlled burns in the National Forest. Federal law does not give them any authority to do so.
Counties and cities do brush management locally often with help from the state in the form of grants. Private land owners are on the hook to accomplish brush clearance for their properties. As a tax payer I don't feel obligated to pay for their brush clearance. Most of these residents in Palisades make more in a year than I will make in ten years. They can afford brush clearance. Shame on them if they didn't do it. Don't blame that on the state. It is not their responsibility. I resent my tax money being spent that way.
virusrex
You made claims that you could not support, that were easily contradicted by arguments you are unable to even address, the article and discussion here is where this is happening.
You only repeat the false claims that were refuted and expect this to somehow make them less debunked, this is what is irrational and not something people would do on purpose.
Except of course if you already know your position can't be defended logically so you opt for empty repetition instead of arguments.
iknowall
That is what I said in the beginning.
Newsom received billions from the federal government to be used for managing forestry, yet we see the result.
Especially with the Pacific Palisades fires, much of which included state parkland that were ignored by State officials in the implementation of forestry management to reduce fire intensity.
A major failure by California's governor.
virusrex
For this argument to have value you would need to demonstrate California had power over federal forests, you have provided no such evidence.
If your argument is that the federal government was the one that failed by not allowing California authority over federal forests then you would have a point, but pretending this was the case when there is nothing to prove it only makes your point valueless.
Not to count that you abandoned your original argument that the climate change related factors did not contribute to the fires (the actual topic of the article). Experts have clearly said this is the case and you have not been able to argue against them.
Zaphod
The name of that science is "propaganda". And yes, we see these scientist at work all over the legacy media.