The work, led by scientists at the Department of Energy’s Pacific Northwest National Laboratory, published today in the journal Geophysical Research Letters.

Regulations put into effect in 2020 by the International Maritime Organization required a roughly 80 percent reduction in the sulfur content of shipping fuel used globally. That reduction meant fewer sulfur aerosols flowed into Earth’s atmosphere.

When ships burn fuel, sulfur dioxide flows into the atmosphere. Energized by sunlight, chemical intermingling in the atmosphere can spur the formation of sulfur aerosols. Sulfur emissions, a form of pollution, can cause acid rain. The change was made to improve air quality around ports.

In addition, water likes to condense on these tiny sulfate particles, ultimately forming linear clouds known as ship tracks, which tend to concentrate along maritime shipping routes. Sulfate can also contribute to forming other clouds after a ship has passed. Because of their brightness, these clouds are uniquely capable of cooling Earth’s surface by reflecting sunlight.

The authors used a machine learning approach to scan over a million satellite images and quantify the declining count of ship tracks, estimating a 25 to 50 percent reduction in visible tracks. Where the cloud count was down, the degree of warming was generally up.

Further work by the authors simulated the effects of the ship aerosols in three climate models and compared the cloud changes to observed cloud and temperature changes since 2020. Roughly half of the potential warming from the shipping emission changes materialized in just four years, according to the new work. In the near future, more warming is likely to follow as the climate response continues unfolding.

Many factors — from oscillating climate patterns to greenhouse gas concentrations — determine global temperature change. The authors note that changes in sulfur emissions aren’t the sole contributor to the record warming of 2023. The magnitude of warming is too significant to be attributed to the emissions change alone, according to their findings.

Due to their cooling properties, some aerosols mask a portion of the warming brought by greenhouse gas emissions. Though aerosols can travel great distances and impose a strong effect on Earth’s climate, they are much shorter-lived than greenhouse gasses.

When atmospheric aerosol concentrations suddenly dwindle, warming can spike. It’s difficult, however, to estimate just how much warming may come as a result. Aerosols are one of the most significant sources of uncertainty in climate projections.

“Cleaning up air quality faster than limiting greenhouse gas emissions may be accelerating climate change,” said Earth scientist Andrew Gettelman, who led the new work.

“As the world rapidly decarbonizes and dials down all anthropogenic emissions, sulfur included, it will become increasingly important to understand just what the magnitude of the climate response could be. Some changes could come quite quickly.”

The work also illustrates that real-world changes in temperature may result from changing ocean clouds, either incidentally with sulfur associated with ship exhaust, or with a deliberate climate intervention by adding aerosols back over the ocean. But lots of uncertainties remain. Better access to ship position and detailed emissions data, along with modeling that better captures potential feedback from the ocean, could help strengthen our understanding.

In addition to Gettelman, Earth scientist Matthew Christensen is also a PNNL author of the work. This work was funded in part by the National Oceanic and Atmospheric Administration.

The research team’s findings show that when decision makers quickly come to a conclusion, the decision is more influenced by their initial bias, or a tendency to err on the side of one of the choices presented. If decision makers wait to gather more information, the slower decision will be less biased. The work was published today in Physical Review E.

“The basic result might seem sort of intuitive, but the mathematics we had to employ to prove this was really non-trivial,” said co-author Bhargav Karamched, an assistant professor in the FSU Department of Mathematics and the Institute of Molecular Biophysics. “We saw that for the first decider in a group, the trajectory of their belief is almost a straight line. The last decider hovers around, going back and forth for a while before making a decision. Even though the underlying equation for each agent’s belief is the same except for their initial bias, the statistics and behavior of each individual is very different.”

The researchers built a mathematical model that represented a group of agents required to decide between two conclusions, one which was correct and one which was incorrect. The model assumed each actor within a group was acting rationally, that is, deciding based off their initial bias and the information they are presented, rather than being swayed by the decisions of individuals around them.

Even with evidence and assuming perfect rationality, bias toward a particular decision caused the earliest deciders in the model to make the wrong conclusion 50% of the time. The more information actors gathered, the more likely they were to behave as if they weren’t biased and to arrive at a correct conclusion.

Of course, in the real world, people are swayed by all sorts of inputs, such as their emotions, the decisions their friends made and other variables. This research offers a metric showing how individuals within a group should make decisions if they are acting rationally. Future research could compare real-world data against this metric to see where people are diverting from optimally rational choices and consider what might have caused their divergence.

The researchers’ model is known as a drift diffusion model, so called because it combines two concepts: individual actor’s tendency to “drift,” or move toward an outcome based on evidence, and the random “diffusion,” or variability of the information presented.

The work could be used, for example, to understand when people are being unduly swayed by early decisions or falling victim to groupthink. It even helps describe other complex scenarios with many individual actors, such as the immune system or the behavior of neurons.

“There is still a lot of work to do to understand decision making in more complicated situations, such as cases where more than two alternatives are presented as choices, but this is a good starting point,” Karamched said.

This research was a multi-institution collaboration involving doctoral candidate Samantha Linn and Associate Professor Sean D. Lawley of the University of Utah, Associate Professor Zachary P. Kilpatrick of the University of Colorado, and Professor Krešimir Josic of the University of Houston.

This research was supported by the National Science Foundation and the National Institutes of Health.

But while the American public quickly learned about the disease during the summer of 2022, as the number of cases declined and media attention waned, much of that knowledge appears to have been lost, according to new survey data from the Annenberg Public Policy Center of the University of Pennsylvania.

In a nationally representative survey of about 1,500 U.S. empaneled adults conducted in July 2024, the policy center finds that knowledge about mpox — which increased from July to August 2022 — has declined, along with fear of the disease (which was previously called monkeypox). This wave of the Annenberg Science and Public Health (ASAPH) knowledge survey finds that:

• Only 1 in 20 Americans (5%) are worried about contracting mpox in the next three months, down from 21% in August 2022. In addition, fewer than 1 in 10 (9%) are worried that they or their families will contract mpox.

• Fewer than 1 in 5 people (17%) know that mpox is less contagious than Covid-19, down from 41% in August 2022. Nearly two-thirds (63%) are not sure.

• Just a third of people (34%) know that men who have sex with men are at a higher risk of infection with mpox, down from nearly two-thirds (63%) in August 2022.

• Less than half (45%) know that a vaccine for mpox exists, down from 61% in August 2022.

• Fewer people (58%) know that it’s false to say that getting a Covid-19 vaccine increases your chances of getting mpox, down from 71%.

“The speed with which the public learned needed information about mpox in the summer of 2022 was a tribute to effective communication by the public health community,” said Kathleen Hall Jamieson, director of the Annenberg Public Policy Center (APPC) and director of the survey. “That same expertise should now be deployed to ensure that those at risk remember mpox’s symptoms, modes of transmission, and the protective power of vaccination.”

Mpox outbreaks in 2024 and 2022

Discovered in 1958, mpox is a rare disease caused by an orthopox virus, and is a less deadly member of the family of viruses that cause smallpox, according to the CDC. Mpox may cause fever, chills, headaches, muscle aches, swollen lymph nodes, and painful rashes, particularly on the hands, feet, face, chest, mouth, or near the genitals. According to the CDC, the disease can spread through contact with infected wild animals, close (including sexual) contact with an infected individual, including contact with scabs or body fluids, or contact with contaminated materials such as towels or bedding.

The current outbreak involves an mpox strain known as clade I, which is especially virulent and dangerous to infants and children under the age of 5, according to the World Health Organization (WHO), whose director general announced this week that he was convening a panel of experts to advise him whether the outbreak should be declared a global health emergency. (The WHO called an end to the 2022 mpox global health emergency in May 2023.) The WHO says there have been over 14,000 cases this year, with at least 511 deaths, according to STAT News. In the Democratic Republic of Congo (DRC), 62% of the deaths involved children under age 5. The current subtype appears to be spread through routine close contact between individuals, though in November 2023 the WHO confirmed that this strain was also being sexually transmitted.

This deadlier strain of monkeypox has not been reported outside central and east Africa, the CDC said.

A different strain of mpox in the 2022 outbreak, known as the clade II subtype, which spread across the United States, was less deadly and largely transmitted through sexual contact, and men who have sex with men were at higher risk of the disease. That earlier strain never disappeared entirely, though new cases are at a much lower level, according to the CDC. The majority of cases are in people who are not vaccinated against mpox or have received only one of the two recommended doses, the CDC reported.

Vaccination against mpox

While knowledge concerning mpox has declined significantly, there has been a less pronounced drop in people’s intentions to get vaccinated against the disease. The CDC has urged individuals to be vaccinated with two doses of the vaccine Jynneos four weeks apart — both for people who have been exposed to mpox virus to help prevent its spread and for people with risk factors for mpox, including men who have sex with men.

An earlier APPC survey, in October 2022, found that 76% of respondents said they were “very likely” or “somewhat likely” to get an mpox vaccine if they were exposed to mpox. The current survey, in July 2024, found a slight decline — 70% of respondents reported that they were either very/somewhat likely to get the vaccine (68%) or were already vaccinated against mpox (2%). However, 3 in 10 (30%) said they were “not too likely” or “not at all likely” to get vaccinated against mpox if exposed to the virus. In addition, 70% reported in July 2024 that they thought the benefits of vaccination against mpox outweighed the risks.

APPC’s ASAPH survey

The survey data come from the 20^th wave of a nationally representative panel of 1,496 U.S. adults, first empaneled in April 2021, conducted for the Annenberg Public Policy Center by SSRS, an independent market research company. This wave of the Annenberg Science and Public Health Knowledge (ASAPH) survey was fielded July 11-18, 2024, and has a margin of sampling error (MOE) of ± 3.6 percentage points at the 95% confidence level. All figures are rounded to the nearest whole number and may not add to 100%.

The researchers developed a method to measure three-dimensional shape changes and analyze how cells behave during this process. Using a physical model based on shape-programming, they found that the movements and rearrangements of cells play a key role in shaping the tissue. This study, published in Science Advances, shows that the shape programming method could be a common way to show how tissues form in animals.

Epithelial tissues are layers of tightly connected cells and make up the basic structure of many organs. To create functional organs, tissues change their shape in three dimensions. While some mechanisms for three-dimensional shapes have been explored, they are not sufficient to explain the diversity of animal tissue forms. For example, during a process in the development of a fruit fly called wing disc eversion, the wing transitions from a single layer of cells to a double layer. How the wing disc pouch undergoes this shape change from a radially symmetric dome into a curved fold shape is unknown.

The research groups of Carl Modes, group leader at the MPI-CBG and the CSBD, and Natalie Dye, group leader at PoL and previously affiliated with MPI-CBG, wanted to find out how this shape change occurs. “To explain this process, we drew inspiration from “shape-programmable” inanimate material sheets, such as thin hydrogels, that can transform into three-dimensional shapes through internal stresses when stimulated,” explains Natalie Dye, and continues: “These materials can change their internal structure across the sheet in a controlled way to create specific three-dimensional shapes. This concept has already helped us understand how plants grow. Animal tissues, however, are more dynamic, with cells that change shape, size, and position.”

To see if shape programming could be a mechanism to understand animal development, the researchers measured tissue shape changes and cell behaviors during the Drosophila wing disc eversion, when the dome shape transforms into a curved fold shape. “Using a physical model, we showed that collective, programmed cell behaviors are sufficient to create the shape changes seen in the wing disc pouch. This means that external forces from surrounding tissues are not needed, and cell rearrangements are the main driver of pouch shape change,” says Jana Fuhrmann, a postdoctoral fellow in the research group of Natalie Dye. To confirm that rearranged cells are the main reason for pouch eversion, the researchers tested this by reducing cell movement, which in turn caused problems with the tissue shaping process.

Abhijeet Krishna, a doctoral student in the group of Carl Modes at the time of the study, explains: “The new models for shape programmability that we developed are connected to different types of cell behaviors. These models include both uniform and direction-dependent effects. While there were previous models for shape programmability, they only looked at one type of effect at a time. Our models combine both types of effects and link them directly to cell behaviors.”

Natalie Dye and Carl Modes conclude: “We discovered that internal stress brought on by active cell behaviors is what shapes the Drosophila wing disc pouch during eversion. Using our new method and a theoretical framework derived from shape-programmable materials, we were able to measure cell patterns on any tissue surface. These tools help us understand how animal tissue transforms their shape and size in three dimensions. Overall, our work suggests that early mechanical signals help organize how cells behave, which later leads to changes in tissue shape. Our work illustrates principles that could be used more widely to better understand other tissue-shaping processes.”

Knowledge of cooling centers in the case of extreme heat

Although the locations of cooling centers, or indoor air-conditioned facilities such as libraries, community and senior centers, schools are publicized by city governments on hot days, many of those surveyed report being unaware of where to find one. Two-thirds of respondents (67%) say they do not know the location of a cooling center to which they could go to in case of extreme heat, a number statistically unchanged from last November. “Communities must do a better job of making the public, especially the most vulnerable, aware of these centers,” said Ken Winneg, managing director of survey research at APPC.

More today see link between extreme heat and climate change.

When compared with an APPC survey in November 2023, significantly more people now say that climate change is increasing the risk of heat-related illnesses, respiratory diseases, and insect-borne diseases. Two-thirds (67%) hold this view vs. just under 6 in 10 (58%) in November 2023.

More people indicate that heat waves in the United States are becoming more frequent and intense than in the past. About two-thirds (65%) believe heat waves are becoming more frequent and intense. Fifty-eight percent (58%) felt this way in November 2023, when we last asked the question. About a quarter (24%) believe heat waves are about as frequent and intense as they have always been, statistically unchanged from our earlier survey.

At the same time, the proportion of people who say extreme heat has often or frequently affected their typical daily activities in the past year has increased significantly. Forty-three percent (43%) say extreme outdoor heat has often (22%) or frequently (21%) affected their daily activities, an 8-point increase compared with November 2023 (35% in total said either “often” or “frequently”).

Signs of heat-related illnesses

Notably, most people also know three of the telltale signs of heat-related illnesses:

• Dizziness (89% compared to 86% in August 2022)
• Nausea (83% compared to 79% in August 2022)
• Hot, red, dry, or damp skin (72%, statistically unchanged from August 2022)
• Cold, pale, and clammy skin (42%, statistically unchanged from August 2022).

Public understands some extreme heat risks better than others

Thinking about the next 10 years, just under 6 in 10 (58%) think that people in their community will be more likely to experience heat stroke caused by extreme heat waves. This is significantly higher than in November 2023 when just over half (52%) said they thought people in their community would be more likely to experience heat stroke caused by extreme heat waves in the next 10 years.

However, only 3 in 10 (30%) know that a pregnant person in the U.S. who is exposed to extreme heat is more likely to deliver their baby early than a pregnant person who is not exposed to extreme heat. About a quarter (23%) incorrectly say that a pregnant person in the U.S. is either less or just as likely to deliver a baby early. Forty-seven percent (47%) are unsure which is correct.

Broad awareness that heat-related deaths are most common among seniors

Two-thirds (67%) know that heat-related deaths are most common among older adults, aged 65 or older, slightly but significantly higher than in August 2022 (62%).

Preventing heat-related illnesses

Nearly all (92%) know that drinking water is better to prevent heat-related illnesses than drinking sugary drinks.

APPC’s ASAPH survey

The survey data come from the 20^th wave of a nationally representative panel of 1,496 U.S. adults, first empaneled in April 2021, conducted for the Annenberg Public Policy Center by SSRS, an independent market research company. This wave of the Annenberg Science and Public Health Knowledge (ASAPH) survey was fielded July 11-18, 2024, and has a margin of sampling error (MOE) of ± 3.6 percentage points at the 95% confidence level. All figures are rounded to the nearest whole number and may not add to 100%. Combined subcategories may not add to totals in the topline and text due to rounding.

Ecological imbalance

Earth and environmental scientists at ETH Zurich led an international team of researchers from the University of Arizona, University of Leeds, CNRS Toulouse, and the Swiss Federal Institute for Forest Snow and Landscape Research (WSL) in a study on how vegetation responds and evolves in response to major climatic shifts and how such shifts affect Earth’s natural carbon-climate regulation system.

Drawing on geochemical analyses of isotopes in sediments, the research team compared the data with a specially designed model, which included a representation of vegetation and its role in regulating the geological climate system. They used the model to test how the Earth system responds to the intense release of carbon from volcanic activity in different scenarios. They studied three significant climatic shifts in geological history, including the Siberian Traps event that caused the Permian-Triassic mass extinction about 252 million years ago. ETH Zurich professor, Taras Gerya points out, “The Siberian Traps event released some 40,000 gigatons (Gt) of carbon over 200,000 years. The resulting increase in global average temperatures between 5 — 10°C caused Earth’s most severe extinction event in the geologic record.”

Move, adapt, or perish

“The recovery of vegetation from the Siberian Traps event took several millions of years and during this time Earth’s carbon-climate regulation system would have been weak and inefficient resulting in long-term climate warming,” explains lead author, Julian Rogger, ETH Zurich.

Researchers found that the severity of such events is determined by how fast emitted carbon can be returned to Earth’s interior — sequestered through silicate mineral weathering or organic carbon production, removing carbon from Earth’s atmosphere. They also found that the time it takes for the climate to reach a new state of equilibrium depended on how fast vegetation adapted to increasing temperatures. Some species adapted by evolving and others by migrating geographically to cooler regions. However, some geological events were so catastrophic that plant species simply did not have enough time to migrate or adapt to the sustained increase in temperature. The consequences of which left its geochemical mark on climate evolution for thousands, possibly millions, of years.

Today’s human-induced climate crisis

What does this mean for human induced climate change? The study found that a disruption of vegetation increased the duration and severity of climate warming in the geologic past. In some cases, it may have taken millions of years to reach a new stable climatic equilibrium due to a reduced capacity of vegetation to regulate Earth’s carbon cycle.

“Today, we find ourselves in a major global bioclimatic crisis,” comments Loïc Pellissier, Professor of Ecosystems and Landscape Evolution at ETH Zurich and WSL. “Our study demonstrates the role of a functioning of vegetation to recover from abrupt climatic changes. We are currently releasing greenhouse gases at a faster rate than any previous volcanic event. We are also the primary cause of global deforestation, which strongly reduces the ability of natural ecosystems to regulate the climate. This study, in my perspective, serves as ‘wake-up call’ for the global community.”