Contrary to what we may imagine about the impact of climate change in Europe, a colder future may be in store. In a new study, researchers from the University of Copenhagen’s Niels Bohr Institute and Department of Mathematical Sciences predict that the system of ocean currents which currently distributes cold and heat between the North Atlantic region and tropics will completely stop if we continue to emit the same levels of greenhouse gases as we do today.

Using advanced statistical tools and ocean temperature data from the last 150 years, the researchers calculated that the ocean current, known as the Thermohaline Circulation or the Atlantic Meridional Overturning Circulation (AMOC), will collapse — with 95 percent certainty — between 2025 and 2095. This will most likely occur in 34 years, in 2057, and could result in major challenges, particularly warming in the tropics and increased storminess in the North Atlantic region.

“Shutting down the AMOC can have very serious consequences for Earth’s climate, for example, by changing how heat and precipitation are distributed globally. While a cooling of Europe may seem less severe as the globe as a whole becomes warmer and heat waves occur more frequently, this shutdown will contribute to an increased warming of the tropics, where rising temperatures have already given rise to challenging living conditions,” says Professor Peter Ditlevsen from the Niels Bohr Institute.

“Our result underscores the importance of reducing global greenhouse gas emissions as soon as possible,” says the researcher.

The calculations, just published in the scientific journal, Nature Communications, contradict the message of the latest IPCC report, which, based on climate model simulations, considers an abrupt change in the thermohaline circulation very unlikely during this century.

Early warning signals present

The researchers’ prediction is based on observations of early warning signals that ocean currents exhibit as they become unstable. These Early Warning Signals for the Thermohaline Circulation have been reported previously, but only now has the development of advanced statistical methods made it possible to predict just when a collapse will occur.

The researchers analysed sea surface temperatures in a specific area of the North Atlantic from 1870 to present days. These sea surface temperatures are “fingerprints” testifying the strength of the AMOC, which has only been measured directly for the past 15 years.

“Using new and improved statistical tools, we’ve made calculations that provide a more robust estimate of when a collapse of the Thermohaline Circulation is most likely to occur, something we had not been able to do before,” explains Professor Susanne Ditlevsen of UCPH’s Department of Mathematical Sciences.

The thermohaline circulation has operated in its present mode since the last ice age, where the circulation was indeed collapsed. Abrupt climate jumps between the present state of the AMOC and the collapsed state has been observed to happen 25 times in connection with iceage climate. These are the famed Dansgaard-Oeschger events first observed in ice cores from the Greenlandic ice sheet. At those events climate changes were extreme with 10-15 degrees changes over a decade, while present days climate change is 1.5 degrees warming over a century.

Facts:

• The Atlantic Meridional Overturning Circulation (AMOC) is part of a global system of ocean currents. By far, it accounts for the most significant part of heat redistribution from the tropics to the northernmost regions of the Atlantic region — not least to Western Europe.
• At the northernmost latitudes, circulation ensures that surface water is converted into deep, southbound ocean currents. The transformation creates space for additional surface water to be moved northward from equatorial regions. As such, thermohaline circulation is critical for maintaining the relatively mild climate of the North Atlantic region.
• The work is supported by TiPES, a joint-European research collaboration focused on tipping points of the climate system. The TiPES project is an EU Horizon 2020 interdisciplinary climate research project focused on tipping points in the climate system.

In September 2019, Virginia Tech Transportation Institute (VTTI) began the first large-scale naturalistic driving study of electric scooter, also known as e-scooter, riders. Over the span of 18 months, 50 scooters, equipped with forward-facing cameras and other research equipment, collected over 9,000 miles of data from over 200,000 rides on Virginia Tech’s Blacksburg campus. Deployment of the scooters began in August 2019. After being removed from campus during the COVID-19 pandemic, they were redeployed in August 2021 through the academic year.

“The e-scooter deployment at Virginia Tech collected the largest naturalistic e-scooter data set known to date and quantified the safety risks associated with behavioral, infrastructure, and environmental factors,” said Elizabeth White, programs and business manager for VTTI. “This was a very exciting research program to be a part of, and our collaboration with many departments on campus was invaluable to ensuring a safe deployment.

White was the lead researcher of the team that included six other Virginia Tech researchers and other industry experts. The results were recently published in published in the Journal of Safety Research.

Utilizing VTTI’s proprietary data acquisition system (DAS), researchers found that infrastructure-related factors, the behaviors of e-scooter riders and other around them, and environmental factors all created risk for e-scooter users. They found loss of control related to infrastructure was the greatest contributor, to all crash- and near-crash events, equating to 47 percent. In total, infrastructure caused 67 percent of incidents, followed by the presence of other road users at 19 percent and rider behavior at 14 percent.

Transitions from surfaces, such as moving from gravel or dirt to grass, proved to be the riskiest. Those riders were almost 60 times more likely to have a crash or near-crash experience. This was supported by data showing that riding off a designated path, or off-road, made users nearly 25 times more likely to experience such issues compared to those who rode on a shared-use path.

uring the study, there were no crashes between an e-scooter and a moving vehicle captured. Conflicts with other road users were shown to be more avoidable through evasive maneuvers when compared to infrastructure-related events. Researchers believe this is likely caused by riders misjudging the terrain or infrastructure or a lack of skill in navigating those obstacles.

VTTI pioneered DAS in the 1990s and it is frequently used by researchers to provide an in-depth look at driver behaviors. These systems allowed rider behavior, interactions with other road users, and other valuable safety data to be recorded and analyzed for various trends. To date, it has been used on everything from e-scooters to semi-trucks. For the e-scooter study, devices did not film the rider, just the riding behavior in order to maintain rider privacy. Riders also were limited to the Blacksburg campus.

To improve safety for riders, the research team recommends all riders engage in an educational outreach program that discusses the significant risks associated with infrastructure, behavior, and environmental factors. Meanwhile, VTTI and its partners will continue to study ways to improve safety around Blacksburg and beyond.

“We are in continued conversations with campus stakeholders to determine the future of micromobility on the Virginia Tech campus,” said White.

The project was funded in part by the Safety Through Disruption, a grant from the U.S. Department of Transportation’s University Transportation Centers program. The research was conducted in partnership with Ford and Spin.

Ford later sold off Spin.

“This discovery is truly captivating as it marks the very first detection of clumps around a young star that have the potential to give rise to giant planets,” says Alice Zurlo, a researcher at the Universidad Diego Portales, Chile, involved in the observations.

The work is based on a mesmerising picture obtained with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument on ESO’s VLT that features fascinating detail of the material around the star V960 Mon. This young star is located over 5000 light-years away in the constellation Monoceros and attracted astronomers’ attention when it suddenly increased its brightness more than twenty times in 2014. SPHERE observations taken shortly after the onset of this brightness ‘outburst’ revealed that the material orbiting V960 Mon is assembling together in a series of intricate spiral arms extending over distances bigger than the entire Solar System.

This finding then motivated astronomers to analyse archive observations of the same system made with ALMA, in which ESO is a partner. The VLT observations probe the surface of the dusty material around the star, while ALMA can peer deeper into its structure. “With ALMA, it became apparent that the spiral arms are undergoing fragmentation, resulting in the formation of clumps with masses akin to those of planets,” says Zurlo.

Astronomers believe that giant planets form either by ‘core accretion’, when dust grains come together, or by ‘gravitational instability’, when large fragments of the material around a star contract and collapse. While researchers have previously found evidence for the first of these scenarios, support for the latter has been scant.

“No one had ever seen a real observation of gravitational instability happening at planetary scales — until now,” says Philipp Weber, a researcher at the University of Santiago, Chile, who led the study published today in The Astrophysical Journal Letters.

“Our group has been searching for signs of how planets form for over ten years, and we couldn’t be more thrilled about this incredible discovery,” says team-member Sebastián Pérez from the University of Santiago, Chile.

ESO instruments will help astronomers unveil more details of this captivating planetary system in the making, and ESO’s Extremely Large Telescope (ELT) will play a key role. Currently under construction in Chile’s Atacama Desert, the ELT will be able to observe the system in greater detail than ever before, collecting crucial information about it. “The ELT will enable the exploration of the chemical complexity surrounding these clumps, helping us find out more about the composition of the material from which potential planets are forming,” concludes Weber.

“Extreme temperature events are becoming more frequent, longer and more intense, and their adverse health effects have drawn growing concern. Another environmental issue worldwide is the presence of fine particulate matter in the air, which may interact synergistically with extreme temperatures to adversely affect cardiovascular health,” said senior author Yuewei Liu, M.D., Ph.D., an associate professor of epidemiology in the School of Public Health at Sun Yat-sen University in Guangzhou, China. “However, it remains unknown if and how co-exposure to extreme temperatures and fine particulate pollution might interact to trigger a greater risk of death from heart attack, which is an acute response potentially brought on by an acute scenario and a great public health challenge due to its substantial disease burden worldwide.”

To examine the impact of extreme temperatures with and without high levels of fine particulate pollution, the researchers analyzed 202,678 heart attack deaths between 2015-2020 that occurred in Jiangsu province, a region with four distinct seasons and a wide range of temperatures and fine particulate pollution levels. The deaths were among older adults with an average age of 77.6 years; 52% were older than age 80; and 52% were male. Particulate exposure on the day of each death and one day before death were included in the analysis.

Extreme temperatures were gauged according to the daily heat index (also referred to as apparent temperature) for an area, which captures the combined effect of both heat and humidity. Both the length and extremeness of heat waves and cold snaps were evaluated. Heart attack deaths, or case days, during these periods were compared with control days on the same day of the week in the same month — meaning that if a death occurred on a Wednesday, all other Wednesdays in the same month would be considered control days. Particulate levels were considered high on any day with an average level of fine particulate matter above 37.5 micrograms per cubic meter.

“Our findings provide evidence that reducing exposure to both extreme temperatures and fine particulate pollution may be useful to prevent premature deaths from heart attack, especially for women and older adults,” Liu said.

Compared with control days, the risk of a fatal heart attack was observed at the following levels:

• 18% higher during 2-day heat waves with heat indexes at or above the 90^th percentile (ranging from 82.6 to 97.9 degrees Fahrenheit), increasing with temperature and duration, and was 74% higher during 4-day heat waves with heat indexes at or above the 97.5^th percentile (ranging from 94.8 to 109.4 degrees Fahrenheit). For context, 6,417 (3.2%) of the 202,678 observed deaths from heart attack happened during heat waves with heat indexes at or above the 95^th percentile (ranging from 91.2 to 104.7 degrees Fahrenheit) for three or more days.
• 4% higher during 2-day cold snaps with temperatures at or below the 10^th percentile (ranging from 33.3 to 40.5 degrees Fahrenheit), increasing with lower temperatures and duration, and was 12% higher during 3-day cold snaps with temperatures at or below the 2.5^th percentile (ranging from 27.0 to 37.2 degrees Fahrenheit). For context, 6,331 (3.1%) of the 202,678 observed deaths from heart attack happened during cold spells with temperatures at or below the 5^th percentile (ranging from 30.0 to 38.5 degrees Fahrenheit) for 3 or more days.
• Twice as high during 4-day heat waves that had fine particulate pollution above 37.5 micrograms per cubic meter. Days with high levels of fine particulate pollution during cold snaps did not have an equivalent increase in the risk of heart attack death.
• Generally higher among women than men during heat waves.
• Higher among people ages 80 and older than in younger adults during heat waves, cold snaps or days with high levels of fine particulate pollution.
• The mean age of all individuals who died from a heart attack in Jiangsu from 2015-2020, including during non-extreme temperature events, was 77.6 years old; 52.1% of these individuals were over 80 years old.

The researchers estimated that up to 2.8% of heart attack deaths may be attributed to the combination of extreme temperatures and high levels of fine particulate pollution (> 37.5 micrograms per cubic meter), according to WHO targets.

“Strategies for individuals to avoid negative health effects from extreme temperatures include following weather forecasts, staying inside when temperatures are extreme, using fans and air conditioners during hot weather, dressing appropriately for the weather, proper hydration and installing window blinds to reduce indoor temperatures,” said Liu. “Using an air purifier in the house, wearing a mask outdoors, staying clear of busy highways when walking and choosing less-strenuous outdoor activities may also help to reduce exposure to air pollution on days with high levels of fine particulate pollution. To improve public health, it is important to take fine particulate pollution into consideration when providing extreme temperature warnings to the public.”

In a 2020 scientific statement and a 2020 policy statement, the American Heart Association details the latest science about air pollution exposure and the individual, industrial and policy measures to reduce the negative impact of poor air quality on cardiovascular health. Reducing exposure to air pollution and reversing the negative impact of poor air quality on cardiovascular health, including heart disease and stroke, is essential to reducing health inequities in Black and Hispanic communities, those that have been historically marginalized and under-resourced, and communities that have the highest levels of exposure to air pollution.

The investigators recommended additional research about the possible interactive effects of extreme weather events and fine particulate pollution on heart attack deaths in areas with different temperature and pollution ranges to confirm their findings. The study did not include adjustments for any adaptive behaviors taken by individuals, such as using air conditioning and staying indoors, when temperatures are extreme or pollution levels are high, which could cause misclassification of individuals’ exposure to weather and alter their risk patterns. These results also may not be generalizable to other regions in China or other countries due to potential variations of adaption capacity and temperature distribution.

Background:

• Fine particulates are less than 2.5 microns in size and may be inhaled deep into the lungs, where they can irritate the lungs and blood vessels around the heart. Most are associated with fuel combustion, such as particles from car exhaust, factory emissions or wildfires.
• Previous research has confirmed that exposure to particulate matter including fine particulates is linked to heart disease, stroke and other health issues.
• For context, the World Health Organization’s target for average annual exposure to fine particulate pollution level is no more than 5 micrograms per cubic meter and no more than 15 micrograms per cubic meter for more than 3-4 days per year.
• In this study, heat waves were defined as periods at or above the 90^th, 92.5^th, 95^th and 97.5^th percentiles of daily heat indexes (ranging from 82.6 to 109.4 degrees Fahrenheit across Jiangsu province, China) for at least 2, 3 or 4 consecutive days.
• Cold spells were defined as periods at or below the 10^th, 7.5^th, 5^th, 2.5^th percentiles of daily heat indexes (ranging from 27 to 40.5 degrees Fahrenheit) for at least 2, 3 or 4 consecutive days.