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Business Standard
10-07-2025
- Climate
- Business Standard
Life-threatening heat domes challenge forecasters amid climate change
Record-breaking temperatures seared the eastern US last month, leading to power emergencies across the region. The cause: an enormous ridge of high pressure that settled on the region, known as a heat dome. This phenomenon has also already struck Europe and China this summer, leading to the temporary closure of the Eiffel Tower and worries about wilting rice crops, respectively. But while heat domes are easy to identify once they strike, they remain difficult to forecast — a problematic prospect in a warming world. 'There is a world of difference between normal summer heat and record or near-record breaking extreme heat,'' said Scott Handel, lead forecaster at the US Climate Prediction Center. 'While normal summer heat can be dangerous, extreme heat can be particularly life threatening.' Heat dome is used to describe extreme heat waves to the general public that captures their menace, said Zach Zobel, a scientist at the Woodwell Climate Research Center. They occur when a large high pressure system settles over a specific area, baking it under stagnant air and the sun's unrelenting energy. That locks in more heat and can intensify the area of high pressure, creating a self-reinforcing cycle. Heat domes can occur at any time of year, but they're particularly dangerous during summer, with wide-ranging societal and economic impacts in the billions. Wildfires and droughts are often the byproduct of extreme heat and have caused some of the largest climate-related disasters in the US. From 1980 to 2024, 23 wildfires caused $147.9 billion in damage and killed 537 people while 32 droughts extracting a toll of $367.6 billion and killed 4,658, according to a database of billion-dollar disasters that was updated until this year by the US Centers for Environmental Information. Between 1979 and 2022, more than 14,000 Americans died directly from heat-related causes according to death certificates, the US Environmental Protection Agency said. In the summer of 2022, an estimated 61,672 people died from heat related causes, according to a July 2023 paper published in the journal of Nature Medicine. A prolonged heat dome can stress crops, particularly heavily traded corn and soybeans. Electricity prices and demand soar when temperatures rise and stay elevated for prolonged periods, said Anthony Chipriano, a forecaster at Vaisala. The dead, hot air under these massive systems can limit the tonnage carried by airliners, kink railroad tracks and crimp the output of wind turbines. For these reasons, meteorologists are opening their toolboxes to try and figure out where and when heat domes will strike. 'I don't have the same ability to predict heat domes like cold air outbreaks, but there are some trends,'' said Judah Cohen, director of seasonal forecasting at Atmospheric and Environmental Research Inc. Meteorologists know, for example, the jet stream — a river of fast-flowing air girdling the globe — naturally migrates northward in summer and they can measure how fast it moves. That metric is known as the Global Atmospheric Angular Momentum, and it's among the best predictors for heat domes, said Matt Rogers, president of the Commodity Weather Group. When the value is low, as it is two weeks ago, 'it can be a leading indicator of widespread, middle latitude heat ridges,'' he said. The latest indication from GLAAM is the return of relatively cooler weather, Rogers said. July is tracking warmer than the 30-year average but cooler than the mean of the last 10 years and the least hot since 2021, he said. Some weather phenomenon like the polar vortex can be spotted several weeks in advance while others like El Nino can be predicted months ahead of time. But heat domes have a much shorter lead time. The US National Weather Service studies probable outcomes of emerging weather patterns, said Handel of Climate Prediction Center, which is what allowed the agency to start issuing heat warnings ahead of the dome that gripped the East Coast even as the region experienced relatively cool weather. The service issued a moderate risk of extreme heat on June 13, when the high temperature in New York's Central Park was still just 78F. Ten days later, the temperature reached 96F, and it hit 99F the day after, both daily records. Federal forecasters also rely on statistical analysis of past patterns compared to what computer models are projecting as well as measures like soil moisture since drier land means higher temperatures to put their heat forecast together. Climate change has warmed the planet, particularly the high latitudes. That influences heat domes in two ways. The first is their northward migration. That phenomenon played out in 2023 as a large ridge of high pressure parked across western-to-central Canada and kicked off a record wildfire season. The second is changes to the jet stream. The temperature gradient between the poles and the tropics helps keep the jet stream taut, allowing it to push weather patterns along after a few days, Zobel said. But as the Arctic warms faster than the rest of the planet, that gradient weakens and is akin to loosening the grip on a rope. The resulting slack can cause the jet stream to kink, bend and buckle. The river of air can also sometimes split, creating a 'kind of a no-man's land' that holds heat domes in place, Cohen said. Still, Arctic warming's exact impact on the jet stream is an area of active research, Simpson said. Some papers haven't been able to show the impacts that adherents of the weakening theory suggest, and others have come up with opposite results. What is clear is that temperatures are rising everywhere, said Karen McKinnon, an associate professor at the Institute of the Environment and Sustainability at the University of California Los Angeles, and it doesn't take that much of an increase on the hottest days to 'make summers feel substantially more extreme.' With more heat trapped in the system and weather patterns that can lock it in place over specific locations, that makes the need for more accurate forecasts with longer lead times all the more important. 'The weather event that kills more than anybody else on the planet is heat and that is certainly true in the United States,' Zobel said. 'It is silently a big human health impact.'
Yahoo
08-07-2025
- Climate
- Yahoo
The science behind Texas' catastrophic floods
Rescue crews are scrambling to find survivors of catastrophic flooding that tore through Central Texas on the Fourth of July. It's already one of the deadliest flood events in modern American history, leaving at least 95 people dead, 27 of whom were girls and counselors at a Christian summer camp in Kerr County, which was inundated when the nearby Guadalupe River surged 26 feet in just 45 minutes. 'It's the worst-case scenario for a very extreme, very sudden, literal wall of water,' said Daniel Swain, a climate scientist at the University of California, Los Angeles, during a livestream Monday morning. 'I don't think that's an exaggeration in this case, based on the eyewitness accounts and the science involved.' It will take some time for scientists to do proper 'attribution' studies here, to say for instance how much extra rain they can blame on climate change. But generally speaking, this disaster has climate change's marks all over it — a perfect storm of conspiring phenomena, both in the atmosphere and on the ground. 'To people who are still skeptical that the climate crisis is real, there's such a clear signal and fingerprint of climate change in this type of event,' said Jennifer Francis, senior scientist at the Woodwell Climate Research Center. This tragedy actually started hundreds of miles to the southeast, out at sea. As the planet has warmed, the gulf has gotten several degrees Fahrenheit hotter. That's turned it into a giant puddle of fuel for hurricanes barreling toward the Gulf Coast, since those storms feed on warm seawater. Even when a hurricane isn't brewing, the gulf is sending more moisture into the atmosphere — think about how your bathroom mirror fogs up when you draw a hot bath. This pushes wet, unstable air higher and higher into the atmosphere, condensing into clouds. As these systems release heat, they grow even more unstable, creating a towering thundercloud that can drop extreme amounts of rainfall. Indeed, preceding the floods, the amount of moisture above Texas was at or above the all-time record for July, according to Swain. 'That is fairly extraordinary, in the sense that this is a place that experiences very moist air this time of year,' Swain said. That meant the system both had the requisite moisture for torrential rainfall, plus the instability that creates the thunderstorms that make that rain fall very quickly. This storm was dumping 2 to 4 inches of rain an hour, and it was moving very slowly, so it essentially stalled over the landscape — a gigantic atmospheric fire hose soaking Central Texas. Making matters worse, the ground in this part of Texas is loaded with limestone, which doesn't readily absorb rainwater compared to places with thick layers of soil at the surface. Rainwater rapidly flowed down hills and valleys and gathered in rivers, which is why the Guadalupe rose so fast. 'That means that not very much of the rain is going to soak into the ground, partly because the soil is shallow and partly because there's steep slopes in the terrain, so that water is able to run off fairly quickly,' said John Nielsen-Gammon, Texas' state climatologist and director of the Southern Regional Climate Center at Texas A&M University. This is exactly the kind of precipitation event that's increasing fastest in a warming climate, Swain added. In California, for instance, alternating periods of extremely wet conditions and extremely dry ones are creating 'weather whiplash.' As the world's bodies of water heat up, more moisture can evaporate into the atmosphere. And due to some basic physics, the warmer it gets, the more moisture the atmosphere can hold, so there's more potential for heavier rainfall. 'The Gulf of Mexico has been going through several marine heat waves recently, and so it's just adding that much more heat to the atmosphere, loading it up for more extreme rainfall events,' said Brett Anderson, senior meteorologist at AccuWeather. 'A lot of these places, 1-in-100-year floods may be becoming more like 1-in-50, even 1-in-10.' AccuWeather's preliminary estimate puts the economic damage of the flooding at between $18 billion and $22 billion. The Trump administration did make deep staffing cuts to the National Oceanic and Atmospheric Administration earlier this year, but it's too early to tell why some people didn't get warnings in time. The National Weather Service did indeed provide multiple flood warnings, and some people are reporting they got alerts on their cell phones, prompting them to escape. Still, with so many people dead or missing, they either didn't get the alerts or didn't adequately understand the danger they were in. Officials in Kerr County previously considered a more robust warning system for Guadalupe River floods, but rejected it as too expensive. For the girls and staff at the summer camp, the deluge arrived at the worst possible time, in the early hours of the morning while they slept. 'In my view — and this seems to be the consensus view of meteorologists — this is not really a failure of meteorology here,' Swain said. 'To my eye, the Weather Service predictions, they certainly weren't perfect, but they were as good as could have been expected given the state of the science.' Swain warns that if the administration follows through on its promises of further more cuts to NOAA, forecasts of flooding could well suffer. 'That really could be catastrophic,' he said. 'That will 100 percent be responsible for costing lives.' Grist has a comprehensive guide to help you stay ready and informed before, during, and after a disaster. Are you affected by the flooding in Texas and North Carolina? Learn how to navigate disaster relief and response. Get prepared. Learn how to be ready for a disaster before you're affected. Explore the full Disaster 101 resource guide for more on your rights and options when disaster hits. This story was originally published by Grist with the headline The science behind Texas' catastrophic floods on Jul 7, 2025.
Yahoo
07-07-2025
- Climate
- Yahoo
The Key Weather Ingredients That Fueled Texas' Deadly Floods
(Bloomberg) -- In Kerrville, Texas, it only rained five times in June, and July started off with just a couple of showers. In fact, the surrounding county was 100% in drought at the start of July. Are Tourists Ruining Europe? How Locals Are Pushing Back Foreign Buyers Swoop on Cape Town Homes, Pricing Out Locals Trump's Gilded Design Style May Be Gaudy. But Don't Call it 'Rococo.' Denver City Hall Takes a Page From NASA In California, Pro-Housing 'Abundance' Fans Rewrite an Environmental Landmark Ironically, that drought helped beget the deadly floods that swept through the region on Friday. It's one of a number of factors, including the abnormally hot Gulf of Mexico, that fueled a storm that killed 27 campers and counselors at Camp Mystic as well as dozens more across Texas. More than a foot of rain fell on Friday, sending the Guadalupe River and other waterways surging over their banks. While researchers haven't analyzed the storm that spawned the floods, extreme precipitation is becoming increasingly common as the planet warms. 'One of the clearest fingerprints of the climate crisis is the uptick in heavy rain events, like the one responsible for the tragedy in Texas this week,' said Jennifer Francis, a climate scientist at the Woodwell Climate Research Center. 'Texas is particularly flood-prone because the fever-hot Gulf of Mexico is right next door, providing plenty of tropical moisture to fuel storms when they come along.' As climate change warms the world, the atmosphere can hold more moisture. For every 1.8F (1C) increase in temperature, the air can carry about 7% more moisture. The mechanics are so well-studied, the formula for it has a name: the Clausius-Clapeyron equation, used to calculate the saturation of water vapor pressure to temperature, said Ryan Truchelut, president of commercial forecaster WeatherTiger. 'The carrying capacity increases faster and faster as the temperature increases,' he said. But that isn't the only issue fueling the mechanics of drought and flood. Warmer temperatures lead to more evaporation, particularly over the ocean. 'Human-caused increases in heat-trapping greenhouse gases have warmed oceans, which evaporate more moisture into the warmer air,' Francis said. 'Not only does this moisture increase rainfall, but it also fuels stronger storms.' The floods also got a boost from moisture flowing north from the remnants of Tropical Storm Barry, which had made landfall on Mexico's east coast a week ago, according to the National Weather Service. In Texas, the situation was also made worse by the drought because dry soils are less able to absorb water when it falls as rain, Truchelut said. Nearly 90% of Kerr County was in either extreme or exceptional drought — the two highest categories on the Drought Monitor's five-step scale — prior to the storm. 'Nothing is going into the parched dirt,' Truchelut said. Soil in that area of Texas isn't known for its water-absorbing qualities even in the best of times, said Tyler Roys, a meteorologist with AccuWeather Inc. When multiple inches of rain fall in an hour, as it did during the storm, 'the ground is going to absorb less,' he said. While the atmosphere is able to carry 7% more water vapor per 1.8F degree, that translates to a 2% to 3% increase in global average rain and snow, according to a review paper co-authored earlier this year by Daniel Swain, a climate scientist at the University of California at Los Angeles. This means a decrease in the number of light-to-moderate rainy days and an uptick in 'the overall number of dry days,' Swain wrote. But at the other end of the spectrum, days with the heaviest rainfall have increased. 'In other words: there's growing evidence not only that precipitation extremes will increase (in general) due to climate change – but also that the most intense, rarest & most dangerous rain events will increase faster than more 'moderate' extremes,' Swain wrote in a post on BlueSky. While there are signs that climate change may have contributed to the extreme rainfall in Texas, larger weather patterns that are typical for summer appear to have added to the volatility. High pressure across the US West and Great Plains led to a dearth of winds aloft to move thunderstorms across Texas, Roys said. That essentially allowed storms to park over the central part of the state, unloading rain over a relatively small geographic area. The storms — which continued into Monday — were part of a larger pattern that started to draw in moisture from the Gulf as well as all around the region, Truchelut said. This became a large rotating system of storms called a mesoscale convective storm complex, which fed off the warm, moist air. In the hours before the flood struck, the US Weather Prediction Center sent a series of mesoscale alerts warning rain could fall at rates of 3 inches (7.6 centimeters) per hour or more in the regions west of Interstate 35, which cuts through the heart of Austin. While natural patterns added to the dangers, Francis noted that cutting emissions would at least lower the risk of human-caused climate change. 'The horrific flooding in Texas is yet another glimpse into our future of more extreme weather, unless we kick our addiction to fossil fuels and stop deforestation,' she said. SNAP Cuts in Big Tax Bill Will Hit a Lot of Trump Voters Too For Brazil's Criminals, Coffee Beans Are the Target 'Telecom Is the New Tequila': Behind the Celebrity Wireless Boom Sperm Freezing Is a New Hot Market for Startups Pistachios Are Everywhere Right Now, Not Just in Dubai Chocolate ©2025 Bloomberg L.P. Error in retrieving data Sign in to access your portfolio Error in retrieving data Error in retrieving data Error in retrieving data Error in retrieving data
Time of India
07-07-2025
- Science
- Time of India
The mysterious black dust speeding up Arctic ice melt: What's behind it?
The Arctic, already warming nearly four times faster than the rest of the planet, faces a new and urgent threat: soot from Canada's record-breaking wildfires is darkening the region's ice and snow, potentially speeding up its melt at an alarming rate. This year, Canada has experienced one of its most severe wildfire seasons on record. According to the Canadian Interagency Forest Fire Centre , over 18 million hectares have burned so far in 2025, surpassing last year's devastating fires. The blazes have sent vast plumes of smoke and soot—known as black carbon—across North America and into the Arctic Circle. Why soot matters in the Arctic? Soot is a powerful climate forcer. When it settles on ice and snow, it reduces their reflectivity, or albedo, causing them to absorb more sunlight instead of reflecting it back into space. This leads to faster warming and melting—a process scientists call the 'albedo effect.' According to the National Snow and Ice Data Center, even a thin layer of black carbon can reduce snow's reflectivity by as much as 10%. Dr. Jennifer Francis, a senior scientist at the Woodwell Climate Research Center, explains: 'The Arctic is like the planet's air conditioner. When soot from wildfires lands on ice, it turbocharges melting. This creates a feedback loop: less ice means more warming, which means more fires and more soot.' Live Events Satellite imagery from NASA 's MODIS instrument shows a marked increase in darkened snow and ice surfaces across the Canadian Arctic Archipelago and Greenland's southern coast this summer. Preliminary data from the European Space Agency's Copernicus program indicate that concentrations of black carbon in the Arctic atmosphere have risen by over 30% compared to the 2010-2020 average. A recent study published in Nature Communications found that wildfire soot could account for up to 25% of the Arctic's recent sea ice loss, a figure that is likely to increase as wildfires become more frequent and intense. The consequences of accelerated Arctic melting are profound. Melting sea ice not only raises global sea levels but also disrupts weather patterns worldwide. The Intergovernmental Panel on Climate Change (IPCC) warns that rapid Arctic warming could destabilize the jet stream, leading to more extreme weather events across the Northern Hemisphere. Scientists are calling for urgent action to both curb greenhouse gas emissions and address the growing threat of wildfire soot. Enhanced monitoring, improved wildfire management, and international cooperation will be critical in protecting the Arctic's fragile climate system.
Japan Today
19-06-2025
- Science
- Japan Today
Study finds planetary waves linked to wild summer weather have tripled since 1950
By SETH BORENSTEIN Climate change has tripled the frequency of atmospheric wave events linked to extreme summer weather in the last 75 years and that may explain why long-range computer forecasts keep underestimating the surge in killer heat waves, droughts and floods, a new study says. In the 1950s, Earth averaged about one extreme weather-inducing planetary wave event a summer, but now it is getting about three per summer, according to a study in Proceedings of the National Academy of Sciences. Planetary waves are connected to 2021's deadly and unprecedented Pacific Northwest heat wave, the 2010 Russian heatwave and Pakistan flooding and the 2003 killer European heatwave, the study said. 'If you're trying to visualize the planetary waves in the northern hemisphere, the easiest way to visualize them is on the weather map to look at the waviness in the jet stream as depicted on the weather map,' said study co-author Michael Mann, a University of Pennsylvania climate scientist. Planetary waves flow across Earth all the time, but sometimes they get amplified, becoming stronger, and the jet stream gets wavier with bigger hills and valleys, Mann said. It's called quasi-resonant amplification or QRA. This essentially means the wave gets stuck for weeks on end, locked in place. As a result, some places get seemingly endless rain while others endure oppressive heat with no relief. 'A classic pattern would be like a high pressure out west (in the United States) and a low pressure back East and in summer 2018, that's exactly what we had,' Mann said. 'We had that configuration locked in place for like a month. So they (in the West) got the heat, the drought and the wildfires. We (in the East) got the excessive rainfall.' 'It's deep and it's persistent,' Mann said. 'You accumulate the rain for days on end or the ground is getting baked for days on end.' The study finds this is happening more often because of human-caused climate change, mostly from the burning of fossil fuels, specifically because the Arctic warms three to four times faster than the rest of the world. That means the temperature difference between the tropics and the Arctic is now much smaller than it used to be and that weakens the jet streams and the waves, making them more likely to get locked in place, Mann said. 'This study shines a light on yet another way human activities are disrupting the climate system that will come back to bite us all with more unprecedented and destructive summer weather events,' said Jennifer Francis, a climate scientist at the Woodwell Climate Research Center who wasn't involved in the research. 'Wave resonance does appear to be one reason for worsening summer extremes. On top of general warming and increased evaporation, it piles on an intermittent fluctuation in the jet stream that keeps weather systems from moving eastward as they normally would, making persistent heat, drought, and heavy rains more likely,' Francis said. This is different than Francis' research on the jet stream and the polar vortex that induces winter extremes, said Mann. There's also a natural connection. After an El Nino, a natural warming of the central Pacific that alters weather patterns worldwide, the next summer tends to be prone to more of these amplified QRA waves that become locked in place, Mann said. And since the summer of 2024 featured an El Nino, this summer will likely be more prone to this type of stuck jet stream, according to Mann. While scientists have long predicted that as the world warms there will be more extremes, the increase has been much higher than what was expected, especially by computer model simulations, Mann and Francis said. That's because the models 'are not capturing this one vital mechanism,' Mann said. Unless society stops pumping more greenhouse gases in the air, 'we can expect multiple factors to worsen summer extremes,' Francis said. 'Heat waves will last longer, grow larger and get hotter. Worsening droughts will destroy more agriculture.' © Copyright 2025 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.
