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Wildfires in Canada — forcing mass evacuations in Manitoba and prompting urgent calls for assistance from First Nations leaders in Saskatchewan — have intensified as heat, drought, and atmospheric conditions collide, during the last week of May 2025.
Climate change is fueling this early-season heat, making high temperatures in parts of central Canada at least five times more likely than they would be in a world without climate change.
Note: This event may continue beyond May 30. Use the Global Climate Shift Index map to stay updated on heat in your region.
Dr. Kristina Dahl, VP of Science at Climate Central, said:
"When temperatures reach a CSI level 5 across such a large area, it’s not just unusual—it means this kind of heat would be incredibly unlikely without climate change," said Dr. Kristina Dahl, VP of Science at Climate Central. "These conditions, which set the stage for dangerous wildfires, will only become more frequent and more severe if we continue burning fossil fuels."
Kaitlyn Trudeau, senior research associate for climate science and wildfire expert at Climate Central, said:
"Climate change-driven heat dries out vegetation and sets the stage for wildfires. Combine that with persistent drought and a locked-in high-pressure system, and you have a perfect storm—one that’s becoming more common as we continue to burn fossil fuels and heat the planet."
To request an interview with a Climate Central scientist, please contact Abbie Veitch at aveitch@climatecentral.org.
The Climate Shift Index uses peer-reviewed methodology and real-time data to estimate how climate change has increased the likelihood of a particular daily temperature.
When we emit carbon dioxide (CO2) into the atmosphere, most of it stays there for centuries or millennia. This means that CO2 emitted even a century ago has contributed to the rising temperatures we see today.
In other words, how much the climate warms depends on how much cumulative CO2 is emitted over time.
The chart shows the ten countries with the largest share of the world’s historical emissions, based on cumulative emissions from fossil fuels and industry since 1750.
The United States has contributed the most, accounting for almost one quarter. This is followed by China and Russia.
As 2023 came to a close, scientists had hoped that a stretch of record heat that emerged across the planet might finally begin to subside this year. It seemed likely that temporary conditions, including an El Niño climate pattern that has always been known to boost average global temperatures, would give way to let Earth cool down.
That didn’t happen.
Instead, global temperatures remain at near-record levels. After 2023 ended up the warmest year in human history by far, 2024 is almost certain to be even warmer. Now, some scientists say this could indicate that fundamental changes are happening to the global climate that are raising temperatures faster than anticipated.
“This shifts the odds towards probably more warming in the pipeline,” said Helge Goessling, a climate physicist at the Alfred Wegener Institute in Germany.
One or two years of such heat, however extraordinary, doesn’t alone mean that the warming trajectory is hastening. Scientists are exploring a number of theories for why the heat has been so persistent.
The biggest factor, they agree, is that the world’s oceans remain extraordinarily warm, far beyond what is usual — warmth that drives the temperature on land up, as well. This could prove to be a temporary phenomenon, just an unlucky two years, and could reverse.
“Temperatures could start plummeting in the next few months and we’d say it was just internal variability. I don’t think we can rule that out yet,” said Zeke Hausfather, a climate scientist at Berkeley Earth. But he added, “I think signs are certainly pointing toward fairly persistent warmth.”
But some scientists are worried the oceans have become so warm that they won’t cool down as much as they historically have, perhaps contributing to a feedback loop that will accelerate climate change.
“The global ocean is warming relentlessly year after year and is the best single indicator that the planet is warming,” said Kevin Trenberth, a distinguished scholar with the National Center for Atmospheric Research.
Other factors are temporary, even if they leave the world a bit hotter. One important one, scientists say, is that years of efforts to clean up air pollutants are having an unintended consequence — removing a layer in the atmosphere that was reflecting some of the sun’s heat back into space.
Whatever the mix of factors or how long they last, scientists say the lack of clear explanation lowers their confidence that climate change will follow the established pattern that models have predicted.
“We can’t rule out eventually much bigger changes,” Hausfather said. “The more we research climate change, the more we learn that uncertainty isn’t our friend.”
Experts had been counting on the end of El Niño to help reverse the trend. The routine global climate pattern, driven by a pool of warmer-than-normal waters across the Pacific, peaked last winter. Usually about five months after El Niño peaks, global average temperatures start to cool down.
Often, that’s because El Niño is quickly replaced with La Niña. Under this pattern, the same strip of Pacific waters become colder than normal, creating a larger cooling effect on the planet. But La Niña hasn’t materialized as scientists predicted it would, either.
That leaves the world waiting for relief as it confronts what is forecast to be its first year above a long-feared threshold of planetary warming: average global temperatures 1.5 degrees Celsius warmer than they were two centuries ago, before humans started burning vast amounts of fossil fuels. (Formally crossing this threshold requires at least several years above it.)
The year 2023 is the current warmest year on record at 1.48 degrees Celsius above the preindustrial average. However, 2024 is expected to be at least 1.55 degrees, breaking the record set the year before. Last year’s record was further above the expected track of global warming than scientists had ever seen, by a margin of more than three tenths of a degree. This year, that margin is expected to be even larger.
While changes in temperatures of a degree or less may seem small, they can have large effects, Trenberth said.
Like “the straw that breaks the camel’s back,” he said.
That includes increasing heat and humidity extremes that are life-threatening, changing ocean heat patterns that could alter critical fisheries, and melting glaciers whose freshwater resources are key to energy generation. And scientists say if the temperature benchmarks are passed for multiple years at time, storms, floods and droughts will increase in intensity, too, with a host of domino effects.
Compared with past years when El Niño has faded, the current conditions are unlike any seen before.
A look at sea surface temperatures following three major El Niño years — 2024, 1998 and 1983 — reveal that a La Niña-like pattern was evident in all three years, with a patch of cooler-than-average conditions emerging in the equatorial Pacific Ocean.
But in 2024, the patch was narrow, unimpressive and dwarfed by warmer-than-average seas that cover most of the planet, including parts of every ocean basin.
Known as marine heat waves, these expansive blobs of unusual oceanic heat are typically defined as seas being much warmer than average, in the highest 10 percent of historical observations, across a wide area for a prolonged period. Strong to severe marine heat waves are occurring in the Atlantic, much of the Pacific, the western and eastern Indian Ocean, and in the Mediterranean Sea.
In October, ocean temperatures at that high threshold covered more than a third of the planet. On the other end, less than 1 percent of the planet had ocean temperatures in the lowest 10 percent of historical values.
Warm and cold ocean temperature extremes should more closely offset each other. But what’s happening is a clear demonstration that oceans, where heat accumulates fastest, are absorbing most of Earth’s energy imbalance. Warm extremes are greatly exceeding cold ones.
That’s a problem because what happens in the ocean doesn’t stay in the ocean.
Because ocean water covers more than 70 percent of Earth, what happens there is critically important to temperatures and humidity on land, with coastal heat waves sometimes fueling terrestrial ones. Weather systems can sometimes linger, producing persistent sunny and wind-free days and bringing ideal conditions for marine heat wave development. These systems can sometimes straddle the land and the ocean, leading to a connected heat wave and transporting humidity.
Trenberth said increasing heat in the oceans, particularly the upper 1,000 feet, is a major factor in the relentless increases in average surface temperatures around the world.
And changes in ocean heat content can affect not just air temperatures, but sea ice, the energy available to storms and water cycles across the planet.
Research has begun to unpack what else may be triggering such changes in global heat.
One recent study found that a reduction in air pollution over the world’s oceans may have contributed to 20 to 30 percent of the warming seen over the North Atlantic and North Pacific, said Andrew Gettelman, a scientist at the Pacific Northwest National Laboratory and the study’s lead author.
Restrictions on sulfur content in the fuels used by shipping liners, put in place in 2020, have dramatically reduced concentrations of sulfur dioxide particles that tend to encourage cloud formation. Though it means lower pollution levels, with fewer clouds, more solar radiation is hitting the oceans and warming them.
A study released Tuesday found that a decline in cloud cover likely contributed to perhaps 0.2 degrees Celsius in previously unexplained warming that hit the planet last year. Goessling and colleagues think that was the product of cleaner shipping emissions, as well as a positive feedback loop in which warming close to Earth’s surface leads to reduced cloud cover, which leads to even more warming.
The study found that in 2023, planetary albedo — the amount of sunlight reflected back into space by light-colored surfaces including clouds, snow and ice cover — may have been at its lowest since at least 1940.
There have also been questions about the roles other factors may be playing, such as an increase in stratospheric water vapor after a 2022 volcanic eruption.
But Earth’s systems are so complex that it’s been impossible to parse what exactly is happening to allow the surge in global temperatures to persist for so long.
“Is this just a blip, or is this actually an acceleration of the warming?” Gettelman said. “That’s the thing everyone is trying to understand right now.”
This year is widely expected to be the warmest year on record, driven largely by the huge stores of ocean heat.
And for now, seasonal model guidance keeps the foot on the accelerator into early 2025, as far as widespread warmer-than-average seas go.
Because of record ocean heat and global temperatures, atmospheric circulation patterns, jet streams and storm tracks across the planet will change. Temperature records will continue to be set.
How big these changes are partly depends on how much warming occurs in the year ahead. But that is unclear because the cooling that usually follows El Niño still hasn’t arrived.
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It’s possible that normal planetary variations are playing a bigger role than scientists expect and that temperatures could soon begin to drop, said Hausfather, who also works for the payments company Stripe.
Even without the cooling influence of a La Niña, a stretch under neutral conditions, with neither a La Niña nor an El Niño, should mean some decline in global average temperatures, he said.
At the same time, if this year’s unusual planetary warmth doesn’t slow down into 2025, there would be nothing to prevent the next El Niño from sending global temperatures soaring — the starting point for the next El Niño would be that much higher. Whether that happens later in 2025 remains to be seen.
But the lack of clarity isn’t a promising sign when some of the most plausible explanations allow for the most extreme global warming scenarios, Hausfather said.
“The fact that we don’t know the answer here is not necessarily comforting to us,” he said.
NATURAL GAS: Federal regulators reinstate their approval of a natural gas pipeline expansion in Maryland, New Jersey, and Pennsylvania, declining to assess the possible impact of the greenhouse gas emissions associated with the project. (Utility Dive)
OFFSHORE WIND: President Trump’s anti-wind executive order will likely pause three of the four offshore wind developments in progress off the coast of New Jersey, experts say. (New Jersey Monitor)
TRANSMISSION:
ELECTRIC VEHICLES: Vermont is the latest state to impose a fee on owners of electric vehicles to make up for lost gas tax revenue, an approach that has been implemented in at least 39 states. (New York Times)
GRID: Public utility regulators in Pennsylvania gather ideas for how to stabilize the state’s “precarious” electric supply as the grid faces rising demand from data centers and growing risks from extreme weather. (Philadelphia Inquirer)
NUCLEAR: New Hampshire’s Seabrook Station nuclear power plant was not damaged in an earthquake that shook New England yesterday. (InDepthNH)
RENEWABLES: Plans are moving forward for a renewable energy generation project on a former Maryland dairy farm owned by the U.S. Navy, though some neighbors are concerned about the possible disturbance of agricultural land. (Capital Gazette, subscription)
HYDRO: A judge’s ruling does nothing to answer questions about the environmental violations an aging hydropower dam in Maine must resolve before it can receive needed permits to continue operations. (Maine Public)
TRANSIT: New York City launches a program allowing food delivery workers to trade in gas mopeds and e-bikes that are not certified for fire safety for new certified e-bikes, as part of an attempt to reduce the fire risks posed by uncertified batteries. (NBC New York)
ELECTRIFICATION:
COMMENTARY:
Second update of the “Indicators of Global Climate Change” research initiative with contributions from MCC. The 1.5-degree Celsius threshold is all but breached.
05.06.2024
Global heating caused by humans is advancing at 0.26 degrees Celsius (°C) per decade – the highest rate since records began, according to research by over 50 leading international scientists. They find that in 2023, global surface temperatures were 1.43°C above their pre-industrial levels, with human activity accounting for 1.3°C of that figure. The “Indicators of Global Climate Change” research initiative is being led by the University of Leeds, and supported by the Berlin-based climate research institute MCC (Mercator Research Institute on Global Commons and Climate Change). The indicator report has now been published in the renowned journal Earth System Science Data.
The report finds that the high rate of heating is driven by consistently high greenhouse gas emissions, equivalent to 53 billion tonnes of CO2 per year. On the other hand, the certain degree of human-caused cooling from particles in the atmosphere is decreasing due to improvements in air quality. High greenhouse gas emission levels are also affecting Earth’s energy balance: ocean buoys and satellites are tracking unprecedented flows of heat into oceans, ice caps, soils and the atmosphere. This flow of heat is 50 percent higher than its long-term average.
“The analysis comes as climate experts meet in Bonn to prepare the ground for the COP29 climate conference in Azerbaijan,” highlights Jan Minx, head of the MCC working group Applied Sustainability Science, and a co-author of the study. “By providing this second data update, we aim to help close the information gap, particularly when climate indicators are changing rapidly.” The authoritative source of scientific information on the state of the climate is the UN’s Intergovernmental Panel on Climate Change (IPCC), but its next major assessment will not happen until around 2027.
According to the new report, the 1.5°C threshold noted in the Paris world climate agreement is all but breached. The central estimate for the remaining carbon budget – how much carbon can be released into the atmosphere to give a 50 percent chance of keeping global temperature rise within 1.5°C – is 200 gigatonnes of CO2 by the start of 2024. This is 60 percent less than 2020, when the IPCC had calculated it at around 500 gigatonnes. (Note: these figures are not comparable with those used in the MCC Carbon Clock, where the annual emission rate is for CO2 only, and the contribution of other greenhouse gases to global heating is subtracted before calculating the remaining carbon budget. Furthermore, the budget is calculated with reference to a 67 rather than 50 percent probability of complying with the temperature limit.)
Piers Forster, Director of the Priestley Centre for Climate Futures Leeds and lead author of the study, says: “Even though climate action has slowed the rise in greenhouse gas emissions, global temperatures are still heading in the wrong direction and faster than ever before. Our analysis is designed to track the long-term trends caused by human activities. Last year, when observed temperature records were broken, natural factors were temporarily adding around 10 percent to the long-term warming.” William Lamb, researcher at MCC and lead author of the study’s emissions section, says: “Until we dramatically reduce deforestation and the combustion of coal, oil and gas, greenhouse gases will continue to accumulate in the atmosphere and drive climate impacts.”
The indicator report is accompanied by an open-data, open-science “Climate Change Tracker” platform. The tracker provides easy access to the key climate indicators.
Further information:
CLIMATE: Earth saw its hottest year on record in 2024, exceeding the previous year’s record and prompting a “red flag” warning from climate scientists as the planet surpassed the Paris Agreement’s 1.5°C warming threshold for the first time. (Associated Press)
SOLAR: Texas and California led the way on the record-breaking additions of 34 GW of new solar and 13 GW in battery storage across the U.S. last year, as 96% of all new generation capacity in 2024 was carbon-free. (Canary Media)
POLITICS:
GRID:
ELECTRIC VEHICLES: Analysts expect electric vehicle sales to jump 30% this year, even though the incoming Trump administration and its threat of tariffs and rolling back the EV tax credit and other incentives could slow the industry’s growth. (Associated Press)
OIL & GAS: Colorado regulators adopt first-in-the-nation rules requiring natural gas gathering and compression facilities to cut greenhouse gas emissions, but advocates say they lack enforcement parameters. (Colorado Sun)
COMMENTARY: Clean fuel standards can make states more independent from the federal government and generate revenue to fund electric vehicle charging infrastructure, the head of a Michigan business group writes. (Utility Dive)
EMISSIONS: Maine has become the latest state to sue major oil and gas companies, alleging they withheld information about the environmental impact of fossil fuels in order to pursue profit. (New York Times)
OFFSHORE WIND: A French energy company has paused its plans to build an offshore wind farm off New York and New Jersey for at least four years, citing President-elect Donald Trump’s opposition to wind as a major factor. (New York Post)
NUCLEAR:
FOSSIL FUELS
CLIMATE
TRANSMISSION:
ELECTRIC VEHICLES: A Vermont aviation company successfully completes a flight of its first electric plane, while the airport in nearby Plattsburgh, New York has been selected as the site for a test flight of the largest fully electric aircraft ever to take to the skies. (VTDigger, NBC5)
GRID: Advocates ask federal regulators to require a private equity firm planning to buy four power plants in PJM territory to disclose whether it plans to sell the energy to data centers, amid concerns the purchase could lead to “unreasonable rates” for customers. (Utility Dive)
COAL: Research out of Johns Hopkins confirms the presence of coal dust in a Baltimore neighborhood near a coal terminal, backing up residents claims that the particles coat their homes and cause health problems. (Baltimore Sun, subscription)
EFFICIENCY: A Michigan-based startup fabricating vacuum-insulated glass for highly efficient windows has opened a new manufacturing plant and secured nearly $83 million in capital and grants to scale up. (Canary Media)
TRANSPORTATION: Environmental advocates and health professionals call on Illinois regulators to adopt stricter tailpipe emission rules for cars and trucks that are modeled off of California’s and exceed national standards. (Chicago Tribune)
ELECTRIC VEHICLES:
SOLAR:
CARBON CAPTURE: A $2 billion carbon capture project at a North Dakota coal plant has been delayed after a key sponsor backs out and financing remains unclear. (E&E News, subscription)
UTILITIES: Investor-owned utilities in Indiana are seeking significant rate increases the “likes of which we’ve never seen,” consumer advocates say, to pay for clean energy and grid infrastructure upgrades. (Post-Tribune)
UTILITIES: Xcel Energy tells Colorado regulators that climate change, wildfire risk and litigation have prompted insurers to increase the utility’s premiums by nearly 400% over last year. (CPR)
ALSO: Wyoming lawmakers look to craft policies to attract more energy-intensive data centers to the state and help utilities deal with associated power demand increases. (WyoFile)
ELECTRIFICATION: A public-private partnership launches a project aimed at decarbonizing a Colorado manufactured-home community by replacing gas appliances with electric ones, bringing in solar power and making other efficiency upgrades. (Utility Dive)
ELECTRIC VEHICLES:
LITHIUM:
POLLUTION: Colorado advocates urge federal regulators to classify the state’s heavily populated Front Range as an “extreme” ozone violator following an abnormally smoggy summer. (CPR)
SOLAR:
CLIMATE:
POLITICS: U.S. Sen. Martin Heinrich, a New Mexico Democrat, touts his support for the SunZia transmission project in a campaign ad, signaling the party’s potential shift toward pushing clean energy infrastructure. (HuffPost)
CLEAN ENERGY: Advocates call on Alaska to tap into its largely unrealized clean energy potential after a report finds the state acquires 2.6% of its electricity from solar, wind and geothermal sources. (Renewable Energy World)
UTILITIES: A new Sierra Club evaluation finds for the fourth year in a row that major U.S. utilities are off track to meet the Biden administration’s emissions reduction goals, and many are in a worse position than last year due to rising demand. (Canary Media)
CLEAN ENERGY:
NUCLEAR: A U.S. Department of Energy report suggests a new serialized approach for designing and building nuclear reactors that would lower upfront costs and meet rising power demand. (Utility Dive)
GRID:
CLIMATE:
ELECTRIC VEHICLES:
OIL & GAS: Natural gas accounted for nearly half of the nation’s energy generation over the summer while coal fell to just 16%, leaving even West Virginia utilities considering a shift to gas. (West Virginia Public Broadcasting)
ELECTRIFICATION: California launches an $80 million program aimed at electrifying low and moderate-income households with rebates for heat pumps, appliances and efficiency upgrades. (Sacramento Bee)
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