WASHINGTON (AP) — Human-caused climate change increased the likelihood and intensity of the hot, dry and windy conditions that fanned the flames of the recent devastating Southern California wildfires, a scientific study found.
But the myriad of causes that go into the still smoldering fires are complex, so the level of global warming's fingerprints on weeks of burning appears relatively small compared to previous studies of killer heat waves, floods and droughts by the international team at World Weather Attribution. Tuesday's report, too rapid for peer-review yet, found global warming boosted the likelihood of high fire weather conditions in this month's fires by 35% and its intensity by 6%.
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FILE - Smoke from a wildfire is seen from the Venice Beach section of Los Angeles, Jan. 7, 2025. (AP Photo/Jae C. Hong, File)
FILE - The Eaton Fire destroys a structure, Jan. 7, 2025, in Altadena, Calif. (AP Photo/Ethan Swope, File)
FILE - A firefighter monitors flames caused by the Hughes Fire along Castaic Lake in Castaic, Calif., Jan. 22, 2025. (AP Photo/Jae C. Hong, File)
FILE - Trees sway in high winds as the Eaton Fire burns structures Jan. 8, 2025, in Altadena, Calif. (AP Photo/Ethan Swope, File)
FILE - Fire crews monitor the Palisades Fire in Mandeville Canyon, Jan. 11, 2025, in Los Angeles. (AP Photo/Jae C. Hong, File)
Once-in-a-decade super strong Santa Ana winds, a dry autumn that followed two very wet years that caused rapid growth in flammable chapparal and grass, hot weather, dry air and vulnerable houses in fire-prone areas all were factors in the fast-moving fires that destroyed thousands of homes and killed at least 29 people, study authors said. But the climate attribution team was only able to quantify issues that dealt with the fire weather index, which are the meteorological conditions that add up to fire danger.
The fire weather index — which includes measurements of past rainfall, humidity and wind speed — is where the team looked and found markers of climate change that they could quantify.
The team used observations of past weather and computer simulations that compared what happened this month to a what-if world without the 1.3 degrees Celsius (2.3 degrees Celsius) of human-caused climate change that Earth has had since industrial times. That allowed them to come up with a calculation for warming's contribution to the disaster. It's a method that the National Academy of Sciences says is valid. Even though these rapid studies aren't yet peer-reviewed, nearly all of them are published later in peer-reviewed journals without significant changes, said World Weather Attribution co-lead scientist Friederike Otto.
“The number (35%) doesn't sound like much” because unlike dozens of its past studies, the team looked at a small area and a complex meteorological measurement in the fire weather index that would generally mean there would be large uncertainties, said Otto, a climate scientist at Imperial College London. But in this case the climate change fingerprint is big enough that it stands out, she said.
Those conditions are part of what makes California attractive to 25 million residents, said study co-author John Abatzoglou, a climate and fire scientist at the University of California Merced.
Southern California has “some of the best climate, best weather on the planet — except when you get a combination of conditions that occurred here," Abatzoglou said. “You get the trifecta of dry windy and warm conditions. Those three things, in combination with dry fuels and ignitions, are the perfect recipe for fire disasters.”
Abatzoglou said it's like a bunch of switches — dryness, fuels, high temperatures, wind and ignition — that all need to be turned on “for conditions to really take off.” Think of it as switches for a light bulb to illuminate — “and so you can think about the artificial warming due to human-caused climate change making the light brighter,” added co-author Park Williams, a UCLA fire and climate scientist.
The study also found California's dry season has increased by 23 days and the lack of rain in October, November and December was more than twice as likely now than in pre-industrial times, but because of limitations on the data, researchers couldn't statistically pinpoint these to both climate change and the specific fires this month, Otto said. But she said “the rains are decreasing — that is because of human-induced climate change.”
Then add in strong winds to whip and spread flames.
Mike Flannigan, a Canadian fire scientist who wasn’t part of the research, said one key to him is the fire season extending longer and “increasing the chance a fire will start during peak Santa Ana winds.”
The research couldn’t specifically quantify how much, if any, climate change affected the Santa Ana winds.
Craig Clements, a climate scientist and director of wildfire study at San Jose State University, said the rapid study makes sense and fits with past research about other fires.
“It's hard to attribute climate change to every fire event as many do,” said Clements, who wasn't part of the research. “If we can state with confidence that the drought is caused by climate change then that is the fingerprint.”
If the world warms another 1.3 degrees Celsius from now, the study said people should expect the type of weather conditions that led to these fires to happen another 35% more often.
Otto said this is not an issue of politics, but science.
“It's not something where you can say that this was because California did something very wrong. They did a lot of things right. They did some things that they could do better,” Otto said. “But what makes these ever more dangerous, these fires, and what is something that the government of California alone can definitely not do anything about is human-induced climate change. And drill, baby drill will make this much, much worse.”
Read more of AP’s climate coverage at http://www.apnews.com/climate-and-environment
Follow Seth Borenstein on X at @borenbears
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FILE - Smoke from a wildfire is seen from the Venice Beach section of Los Angeles, Jan. 7, 2025. (AP Photo/Jae C. Hong, File)
FILE - The Eaton Fire destroys a structure, Jan. 7, 2025, in Altadena, Calif. (AP Photo/Ethan Swope, File)
FILE - A firefighter monitors flames caused by the Hughes Fire along Castaic Lake in Castaic, Calif., Jan. 22, 2025. (AP Photo/Jae C. Hong, File)
FILE - Trees sway in high winds as the Eaton Fire burns structures Jan. 8, 2025, in Altadena, Calif. (AP Photo/Ethan Swope, File)
FILE - Fire crews monitor the Palisades Fire in Mandeville Canyon, Jan. 11, 2025, in Los Angeles. (AP Photo/Jae C. Hong, File)
TORONTO (AP) — Canada’s prime minister and Mexico’s president ordered retaliatory tariffs on goods from the U.S, following through with their threats after U.S. Donald Trump sparked a trade war by imposing sweeping tariffs on imports from Canada, Mexico and China.
Canada had been proactively saying for months that it would respond to any tariffs on Washington's North American allies, while Mexico followed a more cautious approach. But in the end both nations did what they had anticipated: retaliate.
Prime Minister Justin Trudeau and Mexican President Claudia Sheinbaum spoke by phone Saturday after Trump's administration imposed sweeping tariffs — 25% on goods from Canada and Mexico, and 10% on imports from China — although there is still no indication the two countries are coordinating responses or will act in concert in the coming days.
Trudeau's office released a statement about the call with Sheinbaum in which they agreed “to enhance the strong bilateral relations” between Canada and Mexico.
Unlike Mexico, whose president only announced it will impose retaliatory tariffs without mentioning any rate nor products, Trudeau announced Canada will respond with 25% tariffs against $155 billion worth of American goods, including alcohol, furniture and orange juice, and he even suggested Canadians should not buy U.S. products or vacation in the U.S.
“Now is the time to chose products made right here in Canada,” Trudeau posted on X on Sunday.
Canada and Mexico ordered the tariffs late Saturday despite Trump’s further threat to increase the duties charged if retaliatory levies are placed on American goods.
“We’re certainly not looking to escalate but we will stand up for Canada," Trudeau said late Saturday.
At the local level, some authorities in provinces like Ontario, British Columbia and Nova Scotia will remove American liquor brands from government store shelves. Ontario Premier Doug Ford said Sunday the Liquor Control Board of Ontario sells nearly $1 billion worth of American wine, beer, spirits and seltzers every year.
“Not anymore,” Ford said in a statement. “Starting Tuesday, we're removing American products from LCBO shelves. As the only wholesaler of alcohol in the province, LCBO will also remove American products from its catalogue so other Ontario-based restaurants and retailers can't order or restock U.S. products.”
And besides the official responses, people are already thinking on their own ways to face Trump's decision, and one of the initial reactions has been to share in social media lists with alternatives to American products.
Trudeau, in fact, addressed Americans directly, saying they the tariffs “will have real consequences for you.”
Trump responded Sunday, critcizing Canada’s trade surplus with the United States and contending that without that surplus, “Canada ceases to exist as a viable Country. Harsh but true! Therefore, Canada should become our Cherished 51st State. Much lower taxes, and far better military protection for the people of Canada — AND NO TARIFFS!”
Canadians are feeling an undeniable sense of betrayal from their one-time closest allies and friends. Trudeau reminded Americans that Canadian troops fought alongside them in Afghanistan and helped respond to myriad crises from wildfires in California to Hurricane Katrina.
Canadian hockey fans booed the American national anthem at two National Hockey League games on Saturday night.
In Mexico, the official public approach to Trump’s tariff threat has been different , limiting public statements to saying the government was prepared for whatever was coming and that it would ensure the country was respected.
Recalling how in 2019 Mexico was ultimately able to avoid Trump’s tariff threat by adding immigration control to the responsibilities of its newly formed National Guard, Mexico was hoping to dodge the tariffs again or at least find a way to get them lifted quickly.
But the accusation of criminal alliances with Sheinbaum’s administration pushed her to punch back. She called on the U.S. to clean up its own problems with drugs and guns and keep its nose out of Mexico. Trump said he was imposing the tariffs to stop the flow of illegal immigrants and drugs across both the southern and northern U.S. borders.
Beyond the tariffs, academics and diplomats in Mexico harshly criticized the “retaliation clause” Trump included that threatened to raise tariff levels even higher if the targets hit back.
Martha Bárcena, former Mexico ambassador to the U.S. during Trump’s first term, said it’s “very delicate because there has never been such a harsh official statement by the United States government against the Mexican government.”
“It indicates not only a lack of trust, but the consideration of the Mexican government as a national security threat to the United States with all of its implications,” Bárcena said.
Gabriela Siller, director of economic analysis at the Mexican financial group Banco Base, said that the tariffs could trigger an “economic crisis” in Mexico, resulting in a blow for key industries, rising unemployment and price hikes.
In the short term, Sheinbaum’s government would likely have to “apply a countercyclical fiscal policy in Mexico so that there would not be a crash” and take on mounting debt, Siller said.
In the long term, the government would need to seek out new trade agreements, but over-dependence on trade ties with the U.S. will make it hard for Mexico to quickly diversify exports, she said.
After Trump won the election in November, Canadian leaders openly said Mexico was the problem on trade and the border, not Canada. And some have continued to say so.
“I can assure you what President Trump underestimates -- the resilience of the Canadian people, the strength of the Canadian people. No matter what political stripe, we come from Canada, we’re united," Ontario Premier Doug Ford said. “I can tell the American people, Canada is not the problem. The problem is the Mexican border and China. That’s where the problem is.”
The trade war comes as Canada is entering an election cycle. Trudeau's Liberal Party will announce a new leader on March 9 and a spring election is expected.
“Canada will not bow down to a bully," said Mark Carney, considered the frontrunner to replace Trudeau.
Verza contributed from Mexico City. AP writers Megan Janetsky and Fabiola Sánchez also contributed from Mexico City.
President Claudia Sheinbaum waves as she arrives for a Housing for Wellbeing event, a government-funded home improvement program, in Mexico City, Saturday, Feb. 1, 2025. (AP Photo/Marco Ugarte)
FILE - President Claudia Sheinbaum speaks to the crowd during an event marking her first 100 days in office, at the Zócalo, Mexico City's main square, in Mexico City, Sunday, Jan. 12, 2025. (AP Photo/Fernando Llano, File)
FILE - Shelves display bottles of bourbons for sale at a Pennsylvania fine wine and spirits store, Saturday, Jan. 22, 2022, in Harmony, Pa. (AP Photo/Keith Srakocic, File)
FILE - National flags representing the United States, Canada, and Mexico fly in the breeze in New Orleans where leaders of the North American Free Trade Agreement met on April 21, 2008. (AP Photo/Judi Bottoni, File)
Avocados from Mexico are displayed for sale at a Target store in White Plains, N.Y., on Friday, Jan. 31, 2025. (AP Photo/Donald King)
Avocados from Mexico are displayed for sale at a Target store in White Plains, N.Y., on Friday, Jan. 31, 2025. (AP Photo/Donald King)
The flags of Canada and the United States fly outside a hotel in downtown Ottawa, on Saturday, Feb. 1, 2025. (Justin Tang/The Canadian Press via AP)
Canada's Prime Minister Justin Trudeau arrives to address media following the imposition of a raft of tariffs by U.S. President Donald Trump against Canada, Mexico and China, in Ottawa, Saturday, Feb. 1, 2025. (Justin Tang/The Canadian Press via AP)
Canadian Prime Minister Justin Trudeau addresses media members after U.S. President Donald Trump signed an order to impose stiff tariffs on imports from Mexico, Canada and China, in Ottawa, Canada, Saturday, Feb. 1, 2025. (Justin Tang/The Canadian Press via AP)
Canadian Prime Minister Justin Trudeau addresses media members after U.S. President Donald Trump signed an order to impose stiff tariffs on imports from Mexico, Canada and China, in Ottawa, Canada, Saturday, Feb. 1, 2025. (Justin Tang/The Canadian Press via AP)