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Japan Today
13-07-2025
- Science
- Japan Today
Facing climate change, Swiss trees get mist before they're missed
The study is a unique experiment designed to separate out and analyse the different effects of soil drought and air dryness in a natural forest ecosystem By Agnès PEDRERO In a Swiss pine forest, the treetops are being sprayed with mist in a bid to discover the effect that drier or wetter air has on their ability to survive. Eighteen scaffolding towers have been erected between the trees in the Pfynwald in Switzerland's southern Wallis region. High-pressure nozzles mounted on the towers spray vapor over the canopy of some 60 Scots pines, standing 15 meters tall. The study is a unique experiment designed to separate out and analyze the different effects of soil drought and air dryness in a natural forest ecosystem. "The goal is not to spray forests to save them, but to understand why a lack of water in the atmosphere has such a significant impact on forests," project director Charlotte Grossiord told AFP. The trial is being conducted by the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) and the Swiss Federal Institute of Technology in Lausanne (EPFL). The vapour studies aim to measure the rate of dieback in trees, where the leaves and branches start to wither away. It should help experts anticipate when similar forests will be affected, said Giovanni Bortolami, one of the researchers. The objective is to develop forestry strategies and influence the choice of tree species to plant in future, as Switzerland experiences increasingly dry summers. By 2060, there will be 25 percent less rain in the summer and droughts will generally last longer, the environment ministry has said. Another goal is to better understand tree mortality, given that trees "allow us to estimate the concentration of carbon dioxide in the atmosphere", with CO2 being the main climate-warming greenhouse gas, said Grossiord, a professor of plant ecology. The Pfynwald is one of the biggest continuous Scots pine forests in Europe. It counts roughly a thousand trees, all around a century old. At 615 meters above sea level, and surrounded by towering Alpine mountains in the Rhone river valley, the forest is one of the hottest and driest places in Switzerland -- ideal conditions for the researchers. They have been working in the Pfynwald since 2003, studying the dieback of Scots pines due to soil dryness. Some parts of the forest are irrigated, while in others, translucent plastic prevents rainwater from reaching the soil. The mist-creating sprays were introduced last year to study the effects of air dryness, as climate change is resulting in another worrying environmental parameter: thirsty air. At equal humidity, warm air is more "thirsty" than cold air. This "thirst" is called vapour pressure deficit (VPD). VPD is a major factor in determining how much water trees will evaporate through their leaves. With global warming, VPD is increasing, which can cause water stress in vegetation. "Imagine a glass of water in a desert and a glass of water in a rainforest. The temperature is the same. The glass of water empties very quickly in the desert, but not in the rainforest," said Bortolami. It's "exactly the same for trees", which evaporate much more water if the air is drier and therefore "consume water from the soil more quickly", the plant ecophysiology researcher explained. The nozzles diffuse water vapor onto part of the canopy during the day to reduce air "thirst" by about 20 to 30 percent. The researchers then compare the data with the trees that did not get the water vapour spray. Cables on the forest floor are hooked up to sensors on the tree trunks, which continuously measure their diameter and sap flow -- an indicator of water stress. The researchers take other monthly measurements on site. The study will continue until 2028. The initial results show that a lack of water in the soil speeds up the dieback of foliage -- an expected outcome for the researchers. "However, we observed that a dry atmosphere will slow down the dieback process rather than speed it up. That's what really surprised us," said Grossiord. The measurements revealed that with less moisture in the atmosphere, trees close their pores to conserve water. But these acclimatisation mechanisms can only help a tree so much. In the Pfynwald, as in other dry Alpine valleys, Scots pines are dying out while young oak trees, some only waist high, are taking their place. © 2025 AFP
France 24
03-07-2025
- Science
- France 24
Facing climate change, Swiss trees get mist before they're missed
Eighteen scaffolding towers have been erected between the trees in the Pfynwald in Switzerland's southern Wallis region. High-pressure nozzles mounted on the towers spray vapour over the canopy of some 60 Scots pines, standing 15 metres (49 feet) tall. The study is a unique experiment designed to separate out and analyse the different effects of soil drought and air dryness in a natural forest ecosystem. "The goal is not to spray forests to save them, but to understand why a lack of water in the atmosphere has such a significant impact on forests," project director Charlotte Grossiord told AFP. The trial is being conducted by the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) and the Swiss Federal Institute of Technology in Lausanne (EPFL). The vapour studies aim to measure the rate of dieback in trees, where the leaves and branches start to wither away. It should help experts anticipate when similar forests will be affected, said Giovanni Bortolami, one of the researchers. The objective is to develop forestry strategies and influence the choice of tree species to plant in future, as Switzerland experiences increasingly dry summers. By 2060, there will be 25 percent less rain in the summer and droughts will generally last longer, the environment ministry has said. Another goal is to better understand tree mortality, given that trees "allow us to estimate the concentration of carbon dioxide in the atmosphere", with CO2 being the main climate-warming greenhouse gas, said Grossiord, a professor of plant ecology. Thirsty air The Pfynwald is one of the biggest continuous Scots pine forests in Europe. It counts roughly a thousand trees, all around a century old. At 615 metres (2,017 feet) above sea level, and surrounded by towering Alpine mountains in the Rhone river valley, the forest is one of the hottest and driest places in Switzerland -- ideal conditions for the researchers. They have been working in the Pfynwald since 2003, studying the dieback of Scots pines due to soil dryness. Some parts of the forest are irrigated, while in others, translucent plastic prevents rainwater from reaching the soil. The mist-creating sprays were introduced last year to study the effects of air dryness, as climate change is resulting in another worrying environmental parameter: thirsty air. At equal humidity, warm air is more "thirsty" than cold air. This "thirst" is called vapour pressure deficit (VPD). VPD is a major factor in determining how much water trees will evaporate through their leaves. With global warming, VPD is increasing, which can cause water stress in vegetation. "Imagine a glass of water in a desert and a glass of water in a rainforest. The temperature is the same. The glass of water empties very quickly in the desert, but not in the rainforest," said Bortolami. It's "exactly the same for trees", which evaporate much more water if the air is drier and therefore "consume water from the soil more quickly", the plant ecophysiology researcher explained. Surprising results The nozzles diffuse water vapour onto part of the canopy during the day to reduce air "thirst" by about 20 to 30 percent. The researchers then compare the data with the trees that did not get the water vapour spray. Cables on the forest floor are hooked up to sensors on the tree trunks, which continuously measure their diameter and sap flow -- an indicator of water stress. The researchers take other monthly measurements on site. The study will continue until 2028. The initial results show that a lack of water in the soil speeds up the dieback of foliage -- an expected outcome for the researchers. "However, we observed that a dry atmosphere will slow down the dieback process rather than speed it up. That's what really surprised us," said Grossiord. The measurements revealed that with less moisture in the atmosphere, trees close their pores to conserve water. But these acclimatisation mechanisms can only help a tree so much. In the Pfynwald, as in other dry Alpine valleys, Scots pines are dying out while young oak trees, some only waist high, are taking their place. © 2025 AFP
DW
17-06-2025
- Climate
- DW
Drought has many faces and many impacts – DW – 06/17/2025
Extreme drought and water shortages are increasingly harming crops, the economy and the lives of people around the world. But drought doesn't have the same impact everywhere. What can we do to alleviate water crises? After a dry European spring, farmers across some parts of the continent are worried about this year's crops. And the concerns are notunique to Europe. As global temperatures are pushed up by the burning of coal, oil and gas, other parts of the world are also experiencing longer periods of drought. But not all droughts equal, and each type comes with its own set of consequences. Meteorological and agricultural droughts A study released this year by the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) showed that periods of extreme drought have increased globally over the last 40 years. The global average of drought-stricken land has increased by around 50,000 square kilometers (about 19,300 square miles) every year, an area roughly the size of Slovakia. In Sicily, Italy, this former watering hole — once a vital resource for a local farmer — has been reduced to a sandy pit Image: Andrew Medichini/AP Photo/picture alliance People in northern Chile have been living with drought for the last 14 years, while in the southwestern US — states like Arizona, New Mexico and parts of California, for instance — the last three years have been extremely dry. Meteorological drought is defined by comparing actual conditions to the average amount of precipitation in a certain area, making them region specific. The German Weather Service, for examples, calls a meteorological drought a period of one or two months of unusually dry weather, with little precipitation. If the ground is parched, farmers are having trouble securing water, plants aren't growing properly and crops are reduced or even fail completely, it is known as an agricultural drought. Hydrological drought This occurs when water levels in rivers, lakes and underground natural reserves fall below a specific minimum, and freshwater supplies are almost completely dry. Hydrological drought often occurs after a longer meteorological drought. For the German Weather Service, that means a period of at least four months of unusually dry conditions. In October 2024, ships in Brazil's Rio Negro were left high and dry in one of the region's worst droughts since 1950 Image: Bruno Kelly/REUTERS More and more regions around the world are experiencing above-average dryness. By 2050, the World Bank has predicted that people living in much of Africa, Southeast Asia, parts of the US and South America will see even greater problems. In Cyprus, rivers and reservoirs are empty The Mediterranean island of Cyprus is currently experiencing both an agricultural and hydrological drought. Rain has been scarce for many weeks — reservoirs are empty, riverbeds are dry and dusty and farmers don't have enough to keep their crops alive. Recent media reports have said this year's harvest is at risk of failure. "Last year was already bad, but this is the second year that is very dry," said Adriana Bruggeman, an associate professor at the Cyprus Institute's Energy, Environment and Water Research Center. Bruggeman explained that the winter months are usually a time of more precipitation, giving lakes and rivers the chance to refill. But when that rain doesn't fall, the reservoirs in Cyprus remain empty. "We're not in a good condition," she said. Farmers in Cyprus struggle with water shortages To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Socioeconomic drought It's not always easy to strictly differentiate between the different types of drought, as several phenomena can occur in parallel. Most droughts that people actually notice are of the socioeconomic kind, according to Dirk Karger of the WSL in Switzerland. These occur when extremely dry conditions have a direct effect on society and the economy — when the lack of water make certain goods or electricity more expensive, or even scarce. During a period of extreme drought in Spain and Italy in 2024, there were times when water supplies were rationed. In the same period in neighboring France, several nuclear plants had to be temporarily shut down due to insufficient water to cool the reactors. And in Zimbabwe, a hydroelectric plant was unable to provide electricity due to water shortages, resulting in power outages. Droughts can also have dramatic social and economic consequences. In many regions, including Sudan, South Suden and Mali, persistent droughts have exacerbated hunger . "If we look to the West, in the US, where there's been water shortages for the last decade, there have also been repercussions on the water supply," said Karger. "The same thing in Chile, where there's been some real damage." The western states of California and Nevada have experienced months of drought, contributing to the conditions that have saw devastating wildfires during the winter months — most notably in Los Angeles in January. Ecological drought The effects of severe drought, according to Germany's Helmholtz Center for Environmental Research, are often underestimated — even though they often cause much greater economic damage than storms, floods or heavy rain. Unlike these extreme weather events, droughts don't come with an early warning sign. And how bad a drought will end up being is only known long after it has begun. In the US alone, droughts are responsible for between $6-9 billion in damages every year. As a result, researchers are increasingly highlighting a fifth type of event: ecological drought. This describes how periods of extreme drought can destabilize animals, plants and entire ecosystems. How can cities adapt to water cycle 'whiplash'? To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video A severe drop in groundwater levels and soil moisture can lead to irreversible effects for ecosystems — and people. These include widespread crop failure, increased tree death, reduced ecosystem productivity and a threat to water supplies, WSL researchers highlighted in their study. Drought spares no landscape. A severe drought is almost immediately noticeable on grasslands, but these find it easier to bounce back after the rains return. Forests, on the other hand, can't recover as easily and may experience lasting damage from the same weather conditions. Drought also raises the risks in other disasters. A heavy rain after a long period of dryness, for example, can overwhelm dried out soils. The ground can't absorb the sudden masses of water, leading to flooding, landslides and raging mudflows. What can we do to save water and survive drought? To prevent droughts from becoming even more severe in the future, experts say we must do everything to limit climate change as quickly as possible. At the same time, people will need to adapt to increasing long periods without rain. Finding ways to use the available water more efficiently, both at home and in industry, is essential. Places like Singapore are leading the way when it comes to water conservation. This collection basin helps Singapore to collect and efficiently store rainwater Image: Aleksandr Simonov/Depositphotos/Imago Images The city-state in Southeast Asia is a world leader when it comes to collecting rainwater. Water reservoirs have been set up throughout the city, ready to collect any rain that falls from the sky. These reservoirs deliver drinking water during periods of dry weather, and help to cool the city during heat waves. Water treatment plants reclaim wastewater, turning it back into drinking water. So far, Singapore is one of the few countries to do so much to conserve water. Its strategy is an excellent example for other cities and regions, and could help them to prepare for water shortages. Efficiency is another potential way to save water. Around the world, cities lose huge volumes of the precious resource due to leaky or broken pipes. In Italy, some 40% of the country's freshwater is lost on the way to the consumer; in Europe, about a quarter of drinking water is wasted due to inadequate management practices. Regular repair and maintenance of pipes, including regularly checking them for leaks, would help to protect water supplies worldwide. How Singapore is going from water rags to riches To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video This article was originally written in German.
DW
30-05-2025
- Climate
- DW
How does Switzerland predict landslides? – DW – 05/30/2025
Switzerland is a success story in predicting landslides — but more must be done to help the rest of the world prepare for these deadly, unpredictable disasters. The destructive landslide in the Swiss village of Blatten is the latest natural disaster to hit valley communities in the Alpine nation. While Blatten was engulfed by a slick of icy sediment this week, early warnings of a potential landslide gave residents time to evacuate. Only one person — who chose to remain in his home — is currently unaccounted for. The search for him has been suspended. Switzerlandis an early warning success story. Government agencies there use a broad range of technologies and methods to assess risks that could threaten lives and property. This includes terrain mapping and continuous monitoring of rainfall, permafrost melt, groundwater levels, tectonic shifts and ground movement. This data allows authorities to maintain hazard risk maps across the country. "Every community in Switzerland that's affected by a hazard has a hazard map. They're federally mandated for the areas where people live," said Brian McArdell, a geomorphologist at the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL). In Blatten's case, officials issued alerts after a nearby rockfall destabilized the Birch Glacier. Combined with warming summer temperatures, the glacier fractured. A slurry of ice, sediment and mud then roared down the mountain to the village below. Swiss glacier collapse partially destroys village of Blatten To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video "When you slam rock over ice, what you do is liquefy part of the ice," Daniel Farinotti, a glaciologist at ETH Zurich, told DW. "The ice melts, and that lubricates whatever you have." The Blatten landslide was particularly rare. "The sheer size, the amount of material that has been moved there, that's not something you see every day, not every year, not every decade in Switzerland," said Farinotti. "It's kind of a historic event." World's mountainous regions most at risk Steep slopes, unstable terrain and exposure to high rainfall or permafrost melt put mountain regions more at risk of landslides and avalanches. For valley communities in Switzerland, the potential for a landslide can mean entire towns need to be evacuated. Following the Blatten landslide, several nearby communities remain on alert, including for potential flooding. Brienz, a village around 25 miles (41 km) north of Blatten, is also preparing for possible evacuation. The town has faced repeated warningsand "near miss" rockslide events since 2023. "In general, debris flow is a mixture of coarse and fine sediment — so everything from boulders, to mud, to very fine sediments and water," said McArdell. "These events can occur quite suddenly and they're quite, quite dangerous." Regions with the highest landslide-related fatalities globally include the Himalayas, parts of Central and South America, Italy and Iran. A rockslide almost engulfted Brienz in Switzerland in 2023. The city remains on alert for possible evacuations Image: Gian Ehrenzeller/KEYSTONE/picture alliance Predicting landslides remains a challenge While landslides can be forecast, predictions tend to be "probabilistic" rather than precise, Fausto Guzzetti, a now-retired geomorphologist formerly with Italy's Institute for Applied Mathematics and Information Technologies (IMATI), told DW. "We can predict in [a] general area, it could be in a municipality, it can be a catchment," Guzzetti said. Unlike earthquakes and floods, monitoring landslides is far more difficult. While earth tremors can be registered using seismic instruments, and floods can be quickly detected visually, most landslides are unnoticed. "Tens of thousands of landslides simply go unreported," Guzzetti added. "We don't know where they are, and this complicates the ability to forecast them." Even small slides — just a few meters in length — can be deadly, especially if they carry large debris or occur near homes or roads. "A cobble that hits a car or hits a person walking along a road can kill," said Guzzetti, "That's significant." Climate change is also expected to increase rainfall in mountain regions, which in turn is predicted to cause more frequent small-scale landslides. Global call for action Efforts are being made to strengthen international monitoring and preparedness for landslides and glacial melt. Can we survive if the world's glaciers melt? To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video The International Conference on Glaciers' Preservation is currently being held in Tajikistan, where Farinotti expects the release of a "Glacier Declaration" urging greater action to protect ice masses from the effects of climate change. "[It will] call for various actions and, among others, it will call for increased preparedness against risk deriving from cryospheric hazards, so avalanches," he said. Guzzetti also highlighted the UN's Early Warnings for All initiative, which aims to establish a global early warning system by 2027. If achieved, this could be a major step toward saving lives from natural hazards. While wealthy nations like Switzerland have reliable infrastructure to warn communities of potential disasters, many others are still playing catch-up. According to UN figures, only 108 countries had the capacity for "multi-hazard early warning systems" last year though that is more than double the number from 2015. The benefits are clear, said Guzzetti, pointing to the Blatten evacuation: "It seems that they were very good at evacuating the town in time, so that fatalities were nil, or very small." "I think it points to the fact that we are moving in the right direction." Edited by: J. Wingard
Daily Mirror
29-05-2025
- Climate
- Daily Mirror
Swiss glacier wipeout threatens two more villages as dam could burst
The shocking event in Valais on Wednesday, May 28, caused the village of Blatten to be subjected to an immense amount of debris consisting of various pieces of rock and ice. Looming floodwaters are threatening to strike two more Swiss villages in after a glacier collapse saw nearly an entire village become buried under snow. The shocking avalanche in Valais on Wednesday, May 28, saw the village of Blatten subjected to an immense amount of debris consisting of various pieces of rock and ice. It occurred after a chunk of the Birch Glacier in the south of Switzerland fell off, with broken pieces of the wedge tumbling down the mountain and leaving a huge dust cloud in the area around the village, with 90 per cent of the town now being buried in debris. The 300 people who live in Blatten were evacuated before the landslide, but authorities have since stated that one individual is still missing. Following the dramatic turn of events, the two villages of Kippel and Wiler have been ordered to evacuate by authorities as a safety precaution. This is due to the earlier landslide now blocking the river Lonza, creating a makeshift dam that could burst and devastate the two settlements while also sweeping the debris from yesterday's event into the area. Antoine Jacquod, a military security official, told the Keystone-ATS news agency: "'There is a serious risk of an ice jam that could flood the valley below." The army has since made a statement that equipment such as water pumps and diggers were being made available as needed. Christoph Hegg of the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) told Blick:"The lake behind the debris is getting higher and higher. And the water masses are pressing on the dam. This increases the pressure." He added: "The worst case scenario is that the load on the dam becomes too great and the dam breaks. The water masses then rush into the valley and, depending on the strength of the material, are likely to sweep the debris with them." Local politician Christophe Darbellay told news outlet 20 Minuten that Blatten had "disappeared from the map", while locals told the outlet that a sewage treatment facility and power plant which had recently been built could be destroyed by the potential flood posed by the river Lonza. Blatten's president Matthias Bellwald said during a press conference yesterday that the "unimaginable" had happened. He said: "We have lost our village, but not our hearts. "Even though the village lies under a huge pile of rubble, we know where our homes and our church must be rebuilt." Climate change has been proposed as a likely reason for the devastating events seen in the region as a result of the Birch Glacier. Matthias Huss, head of the Glacier Monitoring in Switzerland (GLAMOS), said that rocks in the permafrost zone of the mountain had possibly loosened and contributed to the collapse. He told Reuters:"Unexpected things happen at places that we have not seen for hundreds of years, most probably due to climate change."
