分类： science

This June, a historic, day-and-night heatwave has seared across Western and Southern Europe, bringing dangerous triple-digit temperatures and oppressive humidity to millions of people. A groundbreaking rapid attribution study released Friday by the international climate research collective World Weather Attribution (WWA) has delivered a definitive conclusion: this record-breaking extreme heat event could not have occurred without the influence of human-caused climate change.

The research, which analyzes the current heat dome-fueled heatwave that began spreading across the continent on June 18, draws stark comparisons between modern climate conditions and historical heat patterns. Scientists found that an identical heat event would have been virtually impossible to occur in the climate conditions that existed 50 years ago, in 1976. Compared to the baseline of just 20 years ago, this type of extreme heat is now 200 times more likely to occur.

To put these temperature shifts in context, the study team compared current temperatures to two major historic European heat events, 1976 and 2003, which were previously regarded as extreme benchmarks. Researchers estimate that a comparable heatwave in 1976’s cooler climate would have registered 3.5°C (6.3°F) lower during daytime hours and 2.4°C (4.3°F) lower at night. Even as recently as 2003, the same event would have been 2°C (3.6°F) cooler during the day and 1.3°C (2.3°F) cooler after sunset.

“The increase in temperatures was so dramatic that we would have expected to have never seen this event in the 1976 climate,” explained lead author Theodore Keeping, a climate scientist at Imperial College London’s Centre for Environmental Policy. “And it would also still have been very, very rare, even 23 years ago in 2003.”

WWA, a European-based collaborative network of climate scientists focused on linking extreme weather to climate change, has pioneered rapid event attribution studies since 2015. Their work examines how much of the increased risk of extreme events can be traced back to climate change driven by fossil fuel emissions. While the organization’s rapid studies have not completed full peer review, they rely exclusively on methodology that has already passed peer review, giving their findings broad scientific credibility. For this analysis, the team combined observed on-the-ground temperature data with weather forecast modeling to assess the full scope of the heatwave.

Beyond just air temperature, the study measured combined heat stress, a metric that accounts for both temperature and humidity and directly reflects dangerous strain on the human body. The analysis found that 45 percent of the 850 cities across 30 European countries included in the study have already broken, or are on track to break, all-time records for heat stress. Keeping noted that this combination of extreme heat and high moisture makes the current event far more dangerous than a dry heatwave, as it impairs the body’s ability to cool itself through sweating.

In the researchers’ assessment, this marks the most severe heatwave ever recorded in Northwestern Europe, and the most intense humid heat event ever documented in the region.

Europe is uniquely vulnerable to this type of extreme heat, due to its faster rate of warming compared to the global average. Data from the EU’s Copernicus Climate Change Service confirms that Europe has warmed at twice the global average rate since the 1980s, making it the fastest-warming continent on Earth. A 2023 WWA study found that roughly 1,500 excess deaths were tied to a climate change-fueled European heatwave last summer alone.

Much of the continent also lacks critical infrastructure to handle sustained extreme heat. Most residential and public buildings across Western Europe do not have widespread air conditioning, leaving millions without a reliable way to cool down after the sun sets. Unusually high overnight temperatures during this heatwave have prevented people from recovering from daytime heat exposure, amplifying health risks.

In response to the crisis, national weather agencies across France, Italy, Spain, the United Kingdom and other impacted countries have issued the highest-level red heat alerts. Major sporting events, school sessions, public transit operations and tourist attractions have been restricted or canceled to reduce heat-related risks. France, which has born the brunt of the current heatwave, recorded its hottest all-time national temperature this week, and has already reported 40 drowning deaths as people flocked to bodies of water to find relief from the heat.

Remarkably, researchers found that the current El Niño ocean warming cycle in the Pacific has had no measurable impact on this specific heat event. This June’s heat also follows on the heels of an unprecedented record-breaking heatwave that hit Europe in May 2024, marking an early start to the extreme heat season that typically does not arrive until July and August.

Some outside climate experts say the WWA study may actually understate the role of climate change in driving the extreme heat. Michael Mann, a prominent climate scientist at the University of Pennsylvania who was not involved in the research, noted that the study’s findings are reasonable, but similar attribution analyses have consistently underestimated how much climate change amplifies extreme heat events.
“If anything, this latest assessment — and all similar assessments — are actually underestimating the role that climate change is playing here,” Mann said, pointing to his own separate research on climate change-driven heat stress amplification in North America.

For Keeping and the WWA team, the findings of the study send a clear message to policymakers and communities: extreme heat events like this are no longer rare anomalies, and urgent action is needed both to adapt to unavoidable warming and cut the carbon emissions that are driving climate change.
“We need to expect them to happen. They’re only going to become more frequent in the near term,” Keeping said. “We also need to address the source of climate change as well. And that is very simply carbon emissions from burning fossil fuels.”

Archaeologists from Denmark’s Moesgaard Museum have uncovered an unprecedented large-scale Viking Age industrial site near the city of Aarhus, a discovery that upends long-held outdated stereotypes about Viking societal complexity. Dating back between 600 and 950 CE, spanning the late Iron Age and early Viking Age, the 100,000-square-meter settlement is located in Søften, just 10 kilometers north of Aarhus on the Jutland peninsula.

After a 10-month excavation led by senior archaeologist Liv Stidsing Reher-Langberg, the team confirmed the site’s clear specialization in large-scale textile manufacturing — a feature that sets it apart from all other known Viking-era settlements recorded to date. The dig uncovered over 30 semi-submerged pit houses, structures that served as both workshops and worker accommodations during the Viking period, alongside a dedicated zone for processing raw flax. Artifacts recovered from the site include spindle whorls, loom weights, silver trade coins, decorative glass beads, and domestic pottery, all of which confirm the site’s core function as a centralized production hub.

The layout of the settlement, which separates production areas from craft zones and includes a single distinct residential structure, indicates that the entire operation was overseen and controlled by a powerful authority figure who held centralized control over local resources and output. The discovery did not come as a complete surprise: amateur detectorists had been recovering silver coins from the area for 30 years, and a trial dig conducted 18 months prior, ahead of planned construction for a new highway and industrial park, confirmed the presence of significant ancient remains.

“When we opened the initial test trenches, we quickly realized the site extended far beyond our initial estimates, with pit houses and production features stretching across the entire area,” Reher-Langberg explained of the moment the team grasped the scale of their find.

Moesgaard Museum historian Kasper Andersen noted that the Søften site fills a critical gap in research into the economic, political and social structures of early Viking-era Jutland. At the time, Aarhus — then called Aros — was already a major hub for royal power and international trade, and just four kilometers from Søften, archaeologists uncovered a noble Viking settlement in Lisbjerg just last year. Andersen argues that outlying specialized production sites like Søften supplied goods that fed into Aros’ extensive international trade networks, connecting rural Danish production to markets across Europe and beyond.

“A settlement of this scale and specialization cannot be explained by local demand alone,” Andersen emphasized. “It has to be understood as a node in a much larger, interconnected international commercial network.”

The find directly challenges the pervasive outdated stereotype of Vikings as unorganized, barbaric raiders with no complex social or economic structure. “To create a centralized production site like Søften, you need a highly organized society with structured production lines and established trade outlets for output,” Andersen said. “These textiles were made for a market far larger than the immediate local area.”

Reher-Langberg plans to conduct further analysis, including carbon dating and pollen testing, to answer remaining open questions, such as what specific types of textiles were manufactured at the site and how long the hub operated continuously.

A landmark new study published in *Nature Climate Change* on Monday delivers stark, granular data confirming that decades of human-caused planetary warming have triggered a dramatic, widespread increase in dangerous heat stress across the globe. The research, which moves beyond standard temperature measurements to focus on “feels-like” temperatures that directly impact human health, finds that dozens of nations are now facing one to two additional months of heat stress annually compared to 60 years ago, with heat risk spreading even to regions that historically avoided such dangerous conditions.

Unlike prior climate research that has largely focused on raw air temperature increases, the study led by Rebecca Emerton, a senior scientist at the U.K.-based European Centre for Medium-Range Weather Forecasts, uses the Universal Thermal Climate Index to assess how combined environmental factors—temperature, humidity, wind speed, and more—affect the human body’s ability to regulate its internal heat. This approach provides a far more accurate picture of actual public health risk, because high humidity disrupts sweat evaporation, the human body’s primary natural cooling mechanism, making humid heat waves far more deadly than dry heat events of the same temperature.

The research categorized heat stress into three tiers of increasing risk: strong heat stress (index temperatures ≥ 32°C / 89.6°F), very strong heat stress (≥ 38°C / 100.4°F), and extreme heat stress (≥ 46°C / 114.8°F). Comparing modern data to baseline conditions from the 1970s, the team found that heat stress is intensifying in already warm regions and expanding into new geographic areas.

Hard-hit regions include parts of Southern and Eastern Africa (Namibia, Angola, Tanzania, Kenya, and Uganda), Mexico, and Central America, which could see up to 50 additional days of strong heat stress annually compared to the 1970s. Southern European nations including Southern Spain, Italy, Greece, and Turkey face up to 40 extra days of strong heat stress, with most of Southern Europe recording nearly a full month of additional heat stress days relative to 60 years ago. In the United States, most of the country experiences 15 or more extra days of strong heat stress annually, with southern states like Texas and Florida recording close to 25 or more additional days of very strong heat stress.

Beyond longer heat stress seasons, the study also found that overnight heat is warming faster than daytime heat: the 10 warmest annual nights have warmed by 0.32°C (0.58°F) per decade, compared to 0.27°C (0.49°F) per decade for the 10 warmest annual days. The rise in tropical nights—defined as nights with minimum temperatures of at least 20°C (68°F)—is particularly concerning, because it prevents people from cooling off and recovering from daytime heat exposure, raising the risk of heat-related illness and death. Overall, 1 billion more people around the world now experience at least one day of extreme heat stress annually than they did in the 1970s.

Emerton noted that the expansion of heat stress into previously unaffected regions was one of the study’s most striking findings. “It’s striking to see heat stress not only intensifying in those places that we already consider as being hot or used to experiencing heat waves … but also to see this, we call it, expanding footprint of heat stress expanding into regions where it’s historically been rare or non-existent,” she said.

Jennifer Francis, a climate scientist at the Woodwell Climate Research Center who was not involved in the study, emphasized that the new research adds critical granularity to existing understanding of climate change risks. “This study adds stark details about increasing dangers to billions of humans,” Francis said. “This analysis shows not only is temperature rising, but so is humidity, which makes high temperatures more deadly because our body’s air conditioning system — sweating — struggles to keep up.”

Lead researcher Emerton stressed that the severity of future heat stress increases depends entirely on near-term climate action. The study underscores the urgent need for aggressive cuts to fossil fuel emissions to mitigate future warming, alongside targeted investments in adaptation measures including heat health action plans, early warning systems, and updated climate risk assessments to protect vulnerable communities from rising heat risk.

Archaeologists have announced a groundbreaking discovery near England’s iconic Stonehenge: a 5,500-year-old wooden structure that researchers believe may have served as an early prototype for the famous prehistoric stone monument, predating it by roughly five centuries. The announcement was made Thursday, just days ahead of this year’s summer solstice, the annual event that draws tens of thousands of visitors to the Stonehenge site each year.

The find was made by a team from British archaeological firm Wessex Archaeology, led by veteran archaeologist Phil Harding, a household name in the UK from his decades of work on the popular Channel 4 television series *Time Team*. The dig site is located in Bulford, just 3.1 miles from the main Stonehenge circle on Salisbury Plain, and was carried out between 2015 and 2017 as part of pre-construction archaeology for the UK Ministry of Defense’s troop relocation program. The Ministry is moving thousands of service personnel back to the UK from Germany after decades of large British military presence there, and the Bulford area already hosts a major military barracks within one of the country’s largest training grounds, located near the Stonehenge World Heritage Site.

According to the team’s analysis, the ancient structure was made up of two massive wooden poles set 394 feet apart, positioned to align directly with the rising sun on the summer solstice and the setting sun on the winter solstice — matching the same solar alignment that defines the later Stonehenge stone circle. Along with the remains of the wooden structure, archaeologists uncovered a rich collection of prehistoric artifacts at the site, including Neolithic pottery, ancient animal bones, and a rare disc-shaped stone tool. Harding, 76, said the site was almost certainly a gathering place for large ceremonial religious events held by Neolithic communities 500 years before the iconic stone circle at Stonehenge was completed.

For Harding, a career archaeologist approaching the end of his decades-long fieldwork career, the discovery is a once-in-a-lifetime find. “Opportunities like this probably only come once in a career, in a lifetime,” he said. “I’m probably towards the end of my career now, but thank God I’m still in archaeology long enough to be part of this discovery, because it’s certainly the highlight of my career.”

After the initial excavation wrapped up in 2017, researchers spent years conducting detailed analysis, radiocarbon testing, and site mapping to confirm the structure’s age, alignment, and purpose before announcing their findings to the public. The timing of the announcement, just days before this year’s summer solstice on Sunday, puts a new perspective on the annual celebration that brings druids, pagans, and tourists from across the globe to Stonehenge to mark the longest day of the Northern Hemisphere.

Stonehenge, one of the United Kingdom’s most recognizable cultural symbols and top tourist attractions, is a UNESCO World Heritage Site constructed in stages beginning around 5,000 years ago, with its famous circular stone arrangement erected around 2500 BCE. For decades, scholars have debated the original purpose of the monument. The most widely accepted theory holds that it was a sacred temple intentionally aligned to track the sun’s movement through the annual solar cycle. Other competing theories put forward over the years range from claims it was a coronation site for early Danish kings, a prehistoric healing cult center, a druid ritual site, or even an early astronomical computer capable of predicting solar eclipses and other celestial events.

This new discovery sheds fresh light on the long history of solar ritual practice in the region, showing that Neolithic communities were marking the solstices at the same landscape long before Stonehenge took its current form. As thousands of visitors prepare to gather at Stonehenge to watch the summer solstice sunrise this Sunday, Harding noted that the tradition stretches back far further than many realize. “What few will realize is that 5,000 years ago on a nearby hillside overlooking modern day Bulford, people were doing the exact same thing — revering and celebrating the sunrise on Midsummer’s Day,” he said.

NEW YORK – A groundbreaking international study has pushed back the earliest confirmed evidence of human plague infection by more than 200 years, uncovering pathogen DNA in 5,500-year-old human remains recovered from ancient cemeteries near Siberia’s Lake Baikal. The discovery upends previous timelines for the origins of one of humanity’s deadliest diseases, which has shaped global population history for millennia. The team of genetic researchers published their findings Wednesday in the peer-reviewed journal *Nature*.