Latest news with #UniversityofExeter
Nahar Net
3 days ago
- Science
- Nahar Net
What would happen if the Amazon rainforest dried out?
by Naharnet Newsdesk 30 May 2025, 16:34 A short walk beneath the dense Amazon canopy, the forest abruptly opens up. Fallen logs are rotting, the trees grow sparser and the temperature rises in places sunlight hits the ground. This is what 24 years of severe drought looks like in the world's largest rainforest. But this patch of degraded forest, about the size of a soccer field, is a scientific experiment. Launched in 2000 by Brazilian and British scientists, Esecaflor — short for "Forest Drought Study Project" in Portuguese— set out to simulate a future in which the changing climate could deplete the Amazon of rainfall. It is the longest-running project of its kind in the world, and has become a source for dozens of academic articles in fields ranging from meteorology to ecology and physiology. Understanding how drought can affect the Amazon, an area twice the size of India that crosses into several South American nations, has implications far beyond the region. The rainforest stores a massive amount of carbon dioxide, a greenhouse gas that is the main driver of climate change. According to one study, the Amazon stores the equivalent of two years of global carbon emissions, which mainly come from the burning of coal, oil and gasoline. When trees are cut, or wither and die from drought, they release into the atmosphere the carbon they were storing, which accelerates global warming. Creating drought conditions and observing the results To mimic stress from drought, the project, located in the Caxiuana National Forest, assembled about 6,000 transparent plastic rectangular panels across one hectare (2.5 acres), diverting around 50% of the rainfall from the forest floor. They were set 1 meter above ground (3.3 ft) on the sides to 4 meters (13.1 ft) above ground in the center. The water was funneled into gutters and channeled through trenches dug around the plot's perimeter. Next to it, an identical plot was left untouched to serve as a control. In both areas, instruments were attached to trees, placed on the ground and buried to measure soil moisture, air temperature, tree growth, sap flow and root development, among other data. Two metal towers sit above each plot. In each tower, NASA radars measure how much water is in the plants, which helps researchers understand overall forest stress. The data is sent to the space agency's Jet Propulsion Laboratory in California, where it is processed. "The forest initially appeared to be resistant to the drought," said Lucy Rowland, an ecology professor at the University of Exeter. That began to change about 8 years in, however. "We saw a really big decline in biomass, big losses and mortality of the largest trees," said Rowland. This resulted in the loss of approximately 40% of the total weight of the vegetation and the carbon stored within it from the plot. The main findings were detailed in a study published in May in the journal Nature Ecology & Evolution. It shows that during the years of vegetation loss, the rainforest shifted from a carbon sink, that is, a storer of carbon dioxide, to a carbon emitter, before eventually stabilizing. There was one piece of good news: the decades-long drought didn't turn the rainforest into a savanna, or large grassy plain, as earlier model-based studies had predicted. Next steps include measuring forest recovery In November, most of the 6,000 transparent plastic covers were removed, and now scientists are observing how the forest changes. There is currently no end date for the project. "The forest has already adapted. Now we want to understand what happens next," said meteorologist João de Athaydes, vice coordinator of Esecaflor, a professor at the Federal University of Para and coauthor of the Nature study. "The idea is to see whether the forest can regenerate and return to the baseline from when we started the project." During a visit in April, Athaydes guided Associated Press journalists through the site, which had many researchers. The area was so remote that most researchers had endured a full-day boat trip from the city of Belem, which will host the next annual U.N. climate talks later this year. During the days in the field, the scientists stayed at the Ferreira Penna Scientific Base of the Emilio Goeldi Museum, a few hundred yards (meters) from the plots. Four teams were at work. One collected soil samples to measure root growth in the top layer. Another gathered weather data and tracking soil temperature and moisture. A third was measured vegetation moisture and sap flow. The fourt focused on plant physiology. "We know very little about how drought influences soil processes," said ecologist Rachel Selman, researcher at the University of Edinburgh and one of the co-authors of the Nature study, during a break. Esecaflor's drought simulation draws some parallels with the past two years, when much of the Amazon rainforest, under the influence of El Nino and the impact of climate change, endured its most severe dry spells on record. The devastating consequences ranged from the death of dozens of river dolphins due to warming and receding waters to vast wildfires in old-growth areas. Rowland explained that the recent El Nino brought short-term, intense impacts to the Amazon, not just through reduced rainfall but also with spikes in temperature and vapor pressure deficit, a measure of how dry the air is. In contrast, the Esecaflor experiment focused only on manipulating soil moisture to study the effects of long-term shifts in rainfall. "But in both cases, we're seeing a loss of the forest's ability to absorb carbon," she said. "Instead, carbon is being released back into the atmosphere, along with the loss of forest cover."
The Herald Scotland
3 days ago
- Climate
- The Herald Scotland
Brace for years of extreme heat, UN climate report warns
"We have just experienced the ten warmest years on record," said WMO Deputy Secretary-General Ko Barrett, in a statement. "Unfortunately, this WMO report provides no sign of respite over the coming years, and this means that there will be a growing negative impact on our economies, our daily lives, our ecosystems and our planet." Arctic warming is also predicted to rise at more than three times the global average. "Every additional fraction of a degree of warming drives more harmful heatwaves, extreme rainfall events, intense droughts, melting of ice sheets, sea ice, and glaciers, heating of the ocean, and rising sea levels," the WMO said in a statement. Climate report by the numbers 80% chance that at least one of the next five years will exceed 2024 as the warmest on record 86% chance that at least one of next five years will be more than 1.5 degrees C (2.7 degrees F) above the 1850-1900 average 70% chance that 5-year average warming for 2025-2029 will be more than 1.5 degrees C (2.7 degrees F). Arctic warming predicted to continue to outstrip global average More people at risk Last year, the hottest year on record, saw the first breach of the 2015 Paris climate agreement, which committed countries to avoid global warming of more than 1.5 degrees C. From this year until the end of 2029, the mean near-surface temperature globally is forecast to be between 1.2 degrees C and 1.9 degrees C (2.2 degrees F and 3.4 degrees F) higher than pre-industrial levels of the years 1850-1900, the WMO said, adding that this would fuel more extreme weather. "With the next five years forecast to be more than 1.5 degrees C warmer than preindustrial levels on average, this will put more people than ever at risk of severe heat waves, bringing more deaths and severe health impacts unless people can be better protected from the effects of heat," Richard Betts, head of climate impacts research at the UK Met Office and a professor at the University of Exeter, told the Associated Press. "Also we can expect more severe wildfires as the hotter atmosphere dries out the landscape." Arctic warmth is soaring In the Arctic, the above-average projected warming will accelerate ice melt in the Arctic and northwest Pacific Ocean. The report said Arctic warming was predicted to be more than three-and-a-half times the global average, at 2.4 degrees C (4.3 degrees F) above the recent average temperature over the next five winters. Contributing: Reuters
National Geographic
4 days ago
- Health
- National Geographic
Can you picture an apple in your mind? If not, you might have this condition.
The "apple test"—asking participants to close their eyes and picture an apple—has become a quick way to test how vividly an individual can recall memories. Photograph by Jose A. Bernat Bacete, Getty Close your eyes and imagine an apple. Can you see its shape? What color is it? Is it floating in the air, or being held by a hand, or sitting on a table? If you find yourself struggling, you might have arecently coined condition called aphantasia. People with aphantasia, or 'aphants,' say they lack the ability to effectively visualize in their mind's eye. They might have vivid imaginations, and lead very creative lives, but their brains work a little differently when it comes to visual imagery. Twenty-five years ago, Adam Zeman, a professor of cognitive and behavioral neurology previously at the University of Exeter, now an honorary fellow at the Centre for Clinical Brain Sciences in Edinburgh, was introduced to the curious case of a man who had lost the ability to visualize following a heart procedure. That someone who previously had a vivid mind's eye could suddenly lose it was novel case to Zeman, and one that raised questions about the way imagery functioned within the human brain. Zeman's research on this patient, when published in 2010, resonated with people: ones who hadn't suddenly lost their ability to visualize, but instead had realized, thanks to the description of the patient in the study, that they'd never actually had that ability at all. 'Over the next few years, people began to get in touch saying, I'm just like [the patient], except that I always have been [non-visualizing],' Zeman remembers. He incorporated 21 of these new non-visualizers into a study which he suggested a modified version of the Greek word for imagination—phantasia—to describe those who claimed they had no visual memory. Measuring the mind Psychological studies and self-reporting made up much of the initial research on aphantasia, but this kind of subjective approach tends to provoke skepticism in laypeople, according to Christian Scholz, a PhD student at the Ruhr University Bochum in Germany studying the condition. Skeptics suggest the real difference is not a person's ability to produce a mental image but instead how they differently describe what it's like to conjure a mental image. 'One argument against aphantasia being a real thing is—'well, it's just language anyway,'' he points out. Scholz says 'the people who tend to have more vivid [mental] imagery are also more skeptical of aphantasia'—it's hard for a lifelong visualizer to believe someone else can lack the ability. More recently, scientists have been able to test physiological differences between those who report a strong visual imagination and those who don't. 'If you look into the sun, your pupils constrict. If you have imagery and you imagine looking into the sun, it turns out that your pupils constrict [as well]—and that doesn't happen in people with aphantasia,' Zeman explains, referring to a 2022 study. One study conducted in 2021 attached sensors to the fingertips of participants that measured changes in emotional arousal. Some participants were read a scary story while others were shown scary images. Compared to a control group of those who reported a strong visual memory, aphantasics failed to register fear responses to the stories, though their response to the images was the same as the control group. This indicated to researchers that mental imagery was the mediating factor between something purely conceptual, like a story read aloud, and the listener's gut reaction. Another study published earlier this year measured brain activity in the visual cortex using MRI scans. Results suggested that visualization might be present in aphantasic brains, but only at levels too low for images to be decoded by the conscious mind. 'You see in people with hyperphantasia—vivid imagery—stronger connections between areas at the front of the brain and the [hindbrain] visual network than you do in people with aphantasia,' Zeman explains. A different way to remember the world Sarah Shomstein, a professor of psychological and brain sciences at George Washington University, says the condition is not a disability and could shed light on how human perception and imagination has evolved and continues to evolve. 'There is no damage, there's no deficit,' she says. 'It's a different way [of processing] which has to do with wiring, or some thresholding for activation. And it might be adaptive; it might not be.' She suggests that aphants' brains might be saving energy by processing visual stimuli differently than strong visualizers—rerouted through different areas of the brain that bypass the conscious mind. If it is an adaptive trait, perhaps a larger proportion of the population might grow to have it in the future, she suggests. The apple test is how Shomstein realized that her own ability to form mental images differed from most people. This came well after she'd attained her PhD in cognitive neuroscience, and many years after she dismissed early reports of 'aphantasia' as pseudoscience. That doesn't mean that she, or aphantasics in general, have no imagination. Far from it. 'I can imagine things, I can create very complex imagery,' she explains. 'It is just not in [a] visual form. So for me, everything is black—but I have a concept, I mentalize it.' An individual's unique consciousness Zeman estimates that millions of people around the world have aphantasia—so why is the condition so poorly understood? While the term was only coined in 2015, scientists have been grappling with how to describe differences in perception and memory for centuries. Francis Galton, the prolific 19th century psychologist and founder of eugenics, distributed a questionnaire in 1880 that revealed 12 out of 100 men could not visualize their own breakfast table. W. H. R. Rivers, a prominent psychotherapist who treated shell-shock patients during World War I, lacked the ability to visualize and hypothesized that he had lost it as a child due to a traumatic experience in his home. These observations, however, weren't replicated by formal studies at the time. Tom Ebeyer, founder of the Aphantasia Network community group and an aphant since birth, thinks the condition has been long ignored because there aren't documented negative impacts. 'When you look at outcomes, visualizers and non-visualizers have very common outcomes,' he says. Thousands of visitors to the Aphantasia Network's site have taken the Vividness of Visual Imagery Questionnaire, allowing them to pinpoint their own level of visualization and provide useful data points in understanding the prevalence of aphantasia. According to Ebeyer, members of the 60,000-strong network become artists, architects, authors, and take up other visualization-heavy careers. Both aphants and visualizers report being able to recognize faces of family and friends and navigate their way to familiar places. Another place aphants congregate is the Reddit community /r/Aphantasia, where over 70,000 active members share personal experiences and discuss the latest research on the condition. 'I'd always assumed when people "counted sheep" to sleep or "pictured the audience naked" they were speaking metaphorically,' said one anonymous member of the aphantasia subreddit. 'I would have gone through my whole life never noticing I was different in this way had the subject not come out on the internet,' says subreddit member Megan Lee. But for some members of Ebeyer's Aphantasia Network, they worry their diminished mind's eye cheats them out of memories others might experience vividly. 'I think that's where people see the most impact in their daily life,' he says. 'You can romanticize the ability to relive your past experiences, maybe revisit your loved ones in your mind, see what they look like,' an ability aphantasics feel they lack. Zeman confirms that based on the latest research, 'the most conspicuous consistent difference which emerges [..] is that [aphants] have a rather poor autobiographical memory.' What's next for the aphantasia community? Brought together by an experience which only a small percent of the world's population shares, they are working to develop the vocabulary necessary to describe their experiences and communicate them to researchers. 'It's an intriguing invisible difference,' says Zeman, 'and it reminds us that we all tend to take our own experience as the norm, but actually the experience of others may be very different.'
San Francisco Chronicle
4 days ago
- Science
- San Francisco Chronicle
What would happen if the Amazon rainforest dried out? This decades-long experiment has some answers
CAXIUANA NATIONAL FOREST, Brazil (AP) — A short walk beneath the dense Amazon canopy, the forest abruptly opens up. Fallen logs are rotting, the trees grow sparser and the temperature rises in places sunlight hits the ground. This is what 24 years of severe drought looks like in the world's largest rainforest. But this patch of degraded forest, about the size of a soccer field, is a scientific experiment. Launched in 2000 by Brazilian and British scientists, Esecaflor — short for 'Forest Drought Study Project' in Portuguese— set out to simulate a future in which the changing climate could deplete the Amazon of rainfall. It is the longest-running project of its kind in the world, and has become a source for dozens of academic articles in fields ranging from meteorology to ecology and physiology. Understanding how drought can affect the Amazon, an area twice the size of India that crosses into several South American nations, has implications far beyond the region. The rainforest stores a massive amount of carbon dioxide, a greenhouse gas that is the main driver of climate change. According to one study, the Amazon stores the equivalent of two years of global carbon emissions, which mainly come from the burning of coal, oil and gasoline. When trees are cut, or wither and die from drought, they release into the atmosphere the carbon they were storing, which accelerates global warming. Creating drought conditions and observing the results To mimic stress from drought, the project, located in the Caxiuana National Forest, assembled about 6,000 transparent plastic rectangular panels across one hectare (2.5 acres), diverting around 50% of the rainfall from the forest floor. They were set 1 meter above ground (3.3 ft) on the sides to 4 meters (13.1 ft) above ground in the center. The water was funneled into gutters and channeled through trenches dug around the plot's perimeter. Next to it, an identical plot was left untouched to serve as a control. In both areas, instruments were attached to trees, placed on the ground and buried to measure soil moisture, air temperature, tree growth, sap flow and root development, among other data. Two metal towers sit above each plot. In each tower, NASA radars measure how much water is in the plants, which helps researchers understand overall forest stress. The data is sent to the space agency's Jet Propulsion Laboratory in California, where it is processed. 'The forest initially appeared to be resistant to the drought," said Lucy Rowland, an ecology professor at the University of Exeter. That began to change about 8 years in, however. "We saw a really big decline in biomass, big losses and mortality of the largest trees,' said Rowland. This resulted in the loss of approximately 40% of the total weight of the vegetation and the carbon stored within it from the plot. The main findings were detailed in a study published in May in the journal Nature Ecology & Evolution. It shows that during the years of vegetation loss, the rainforest shifted from a carbon sink, that is, a storer of carbon dioxide, to a carbon emitter, before eventually stabilizing. There was one piece of good news: the decades-long drought didn't turn the rainforest into a savanna, or large grassy plain, as earlier model-based studies had predicted. Next steps include measuring forest recovery In November, most of the 6,000 transparent plastic covers were removed, and now scientists are observing how the forest changes. There is currently no end date for the project. 'The forest has already adapted. Now we want to understand what happens next,' said meteorologist João de Athaydes, vice coordinator of Esecaflor, a professor at the Federal University of Para and coauthor of the Nature study. 'The idea is to see whether the forest can regenerate and return to the baseline from when we started the project.' During a visit in April, Athaydes guided Associated Press journalists through the site, which had many researchers. The area was so remote that most researchers had endured a full-day boat trip from the city of Belem, which will host the next annual U.N. climate talks later this year. During the days in the field, the scientists stayed at the Ferreira Penna Scientific Base of the Emilio Goeldi Museum, a few hundred yards (meters) from the plots. Four teams were at work. One collected soil samples to measure root growth in the top layer. Another gathered weather data and tracking soil temperature and moisture. A third was measured vegetation moisture and sap flow. The fourt focused on plant physiology. "We know very little about how drought influences soil processes,' said ecologist Rachel Selman, researcher at the University of Edinburgh and one of the co-authors of the Nature study, during a break. Esecaflor's drought simulation draws some parallels with the past two years, when much of the Amazon rainforest, under the influence of El Nino and the impact of climate change, endured its most severe dry spells on record. The devastating consequences ranged from the death of dozens of river dolphins due to warming and receding waters to vast wildfires in old-growth areas. Rowland explained that the recent El Nino brought short-term, intense impacts to the Amazon, not just through reduced rainfall but also with spikes in temperature and vapor pressure deficit, a measure of how dry the air is. In contrast, the Esecaflor experiment focused only on manipulating soil moisture to study the effects of long-term shifts in rainfall. 'But in both cases, we're seeing a loss of the forest's ability to absorb carbon,' she said. 'Instead, carbon is being released back into the atmosphere, along with the loss of forest cover.' ___
Yahoo
4 days ago
- Health
- Yahoo
What would happen if the Amazon rainforest dried out? This decades-long experiment has some answers
CAXIUANA NATIONAL FOREST, Brazil (AP) — A short walk beneath the dense Amazon canopy, the forest abruptly opens up. Fallen logs are rotting, the trees grow sparser and the temperature rises in places sunlight hits the ground. This is what 24 years of severe drought looks like in the world's largest rainforest. But this patch of degraded forest, about the size of a soccer field, is a scientific experiment. Launched in 2000 by Brazilian and British scientists, Esecaflor — short for 'Forest Drought Study Project' in Portuguese— set out to simulate a future in which the changing climate could deplete the Amazon of rainfall. It is the longest-running project of its kind in the world, and has become a source for dozens of academic articles in fields ranging from meteorology to ecology and physiology. Understanding how drought can affect the Amazon, an area twice the size of India that crosses into several South American nations, has implications far beyond the region. The rainforest stores a massive amount of carbon dioxide, a greenhouse gas that is the main driver of climate change. According to one study, the Amazon stores the equivalent of two years of global carbon emissions, which mainly come from the burning of coal, oil and gasoline. When trees are cut, or wither and die from drought, they release into the atmosphere the carbon they were storing, which accelerates global warming. Creating drought conditions and observing the results To mimic stress from drought, the project, located in the Caxiuana National Forest, assembled about 6,000 transparent plastic rectangular panels across one hectare (2.5 acres), diverting around 50% of the rainfall from the forest floor. They were set 1 meter above ground (3.3 ft) on the sides to 4 meters (13.1 ft) above ground in the center. The water was funneled into gutters and channeled through trenches dug around the plot's perimeter. Next to it, an identical plot was left untouched to serve as a control. In both areas, instruments were attached to trees, placed on the ground and buried to measure soil moisture, air temperature, tree growth, sap flow and root development, among other data. Two metal towers sit above each plot. In each tower, NASA radars measure how much water is in the plants, which helps researchers understand overall forest stress. The data is sent to the space agency's Jet Propulsion Laboratory in California, where it is processed. 'The forest initially appeared to be resistant to the drought," said Lucy Rowland, an ecology professor at the University of Exeter. That began to change about 8 years in, however. "We saw a really big decline in biomass, big losses and mortality of the largest trees,' said Rowland. This resulted in the loss of approximately 40% of the total weight of the vegetation and the carbon stored within it from the plot. The main findings were detailed in a study published in May in the journal Nature Ecology & Evolution. It shows that during the years of vegetation loss, the rainforest shifted from a carbon sink, that is, a storer of carbon dioxide, to a carbon emitter, before eventually stabilizing. There was one piece of good news: the decades-long drought didn't turn the rainforest into a savanna, or large grassy plain, as earlier model-based studies had predicted. Next steps include measuring forest recovery In November, most of the 6,000 transparent plastic covers were removed, and now scientists are observing how the forest changes. There is currently no end date for the project. 'The forest has already adapted. Now we want to understand what happens next,' said meteorologist João de Athaydes, vice coordinator of Esecaflor, a professor at the Federal University of Para and coauthor of the Nature study. 'The idea is to see whether the forest can regenerate and return to the baseline from when we started the project.' During a visit in April, Athaydes guided Associated Press journalists through the site, which had many researchers. The area was so remote that most researchers had endured a full-day boat trip from the city of Belem, which will host the next annual U.N. climate talks later this year. During the days in the field, the scientists stayed at the Ferreira Penna Scientific Base of the Emilio Goeldi Museum, a few hundred yards (meters) from the plots. Four teams were at work. One collected soil samples to measure root growth in the top layer. Another gathered weather data and tracking soil temperature and moisture. A third was measured vegetation moisture and sap flow. The fourt focused on plant physiology. "We know very little about how drought influences soil processes,' said ecologist Rachel Selman, researcher at the University of Edinburgh and one of the co-authors of the Nature study, during a break. Esecaflor's drought simulation draws some parallels with the past two years, when much of the Amazon rainforest, under the influence of El Nino and the impact of climate change, endured its most severe dry spells on record. The devastating consequences ranged from the death of dozens of river dolphins due to warming and receding waters to vast wildfires in old-growth areas. Rowland explained that the recent El Nino brought short-term, intense impacts to the Amazon, not just through reduced rainfall but also with spikes in temperature and vapor pressure deficit, a measure of how dry the air is. In contrast, the Esecaflor experiment focused only on manipulating soil moisture to study the effects of long-term shifts in rainfall. 'But in both cases, we're seeing a loss of the forest's ability to absorb carbon,' she said. 'Instead, carbon is being released back into the atmosphere, along with the loss of forest cover.' ___ The Associated Press' climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP's standards for working with philanthropies, a list of supporters and funded coverage areas at
