Date: March 28, 2019 Source: Georgetown University Medical Center Summary: As many as a billion people could be newly exposed to disease-carrying mosquitoes by the end of the century because of global warming, says a new study that examines temperature changes on a monthly basis across the world. Share:
As many as a billion people could be newly exposed to disease-carrying mosquitoes by the end of the century because of global warming, says a new study that examines temperature changes on a monthly basis across the world. Scientists say the news is bad even in areas with only a slight risk of having a climate suited for mosquitoes, because the viruses they carry are notorious for explosive outbreaks when they show up at the right place under the right conditions. "Climate change is the largest and most comprehensive threat to global health security," says global change biologist Colin J. Carlson, PhD, a postdoctoral fellow in Georgetown University's biology department, and co-lead author of the new study. "Mosquitoes are only a part of the challenge, but after the Zika outbreak in Brazil in 2015, we're especially worried about what comes next." Published in the open access journal PLOS Neglected Tropical Diseases ("Global expansion and redistribution of Aedes-borne virus transmission risk with climate change"), the research team led by Sadie J. Ryan of the University of Florida and Carlson, studied what would happen if the two most common disease-carrying mosquitoes -- Aedes aegypti and Aedes albopictus -- track and move as the temperature changes over decades. According to the World Health Organization, mosquitoes are one of the deadliest animals in the world, carrying diseases that cause millions of deaths every year. Both Aedes aegypti and Aedes albopictus can carry the dengue, chikunguyna and Zika viruses, as well as at least a dozen other emerging diseases that researchers say could be a threat in the next 50 years. With global warming, the scientists say, almost all of the world's population could be exposed at some point in the next 50 years. As the temperature increases, they expect year-round transmissions in the tropics and seasonal risks almost everywhere else. A greater intensity of infections is also predicted. "These diseases, which we think of as strictly tropical, have been showing up already in areas with suitable climates, such as Florida, because humans are very good at moving both bugs and their pathogens around the globe," explains Ryan, associate professor of medical geography at Florida. "The risk of disease transmission is a serious problem, even over the next few decades," Carlson says. "Places like Europe, North America, and high elevations in the tropics that used to be too cold for the viruses will face new diseases like dengue." More severe climate change would produce proportionally worse population exposures for the Aedes aegypti mosquito. But in areas with the worst climate increase, including west African and southeast Asia, serious reductions are expected for the Aedes albopictus mosquito, most noticeably in southeast Asia and west Africa. This mosquito carries dengue, chikunguyna and Zika. "Understanding the geographic shifts of risks really puts this in perspective," Ryan says. "While we may see changing numbers and think we have the answer, imagine a world too hot for these mosquitoes." "This might sound like a good news, bad news scenario but it's all bad news if we end up in the worst timeline for climate change," Carlson says. "Any scenario where a region gets too warm to transmit dengue is one where we also have different but equally severe threats in other health sectors." The team of researchers looked at temperatures month by month to project risk through 2050 and 2080. The modeling did not predict which type of mosquito would migrate, but rather accounted for a climate where their spread would not be prevented. "Based on what we know about mosquito movement from region to region, 50 years is a considerable long time and we expect significant spread of both types of insects, particularly Aedes aegypti, which thrive in urban environments," Carlson explains. "This is only one study to begin understanding the fast-approaching challenges we face with global warming," Carlson says. "We have a Herculean task ahead. We need to figure out pathogen by pathogen, region by region, when problems will emerge so that we can plan a global health response." In addition to Ryan and Carlson, study authors include Erin A. Mordecai of Stanford University, and Leah R. Johnson of Virginia Polytechnic and State University. This work was supported by: the National Science Foundation (DEB-1518681, DEB-1641145, and DEB-1640780), Centers for Disease Control and Prevention (1U01CK000510-01), Southeastern Regional Center of Excellence in Vector-Borne Diseases: the Gateway Program, the Stanford Woods Institute for the Environment, and the Stanford Center for Innovation in Global Health. Story Source: Materials provided by Georgetown University Medical Center. Note: Content may be edited for style and length. Knight Man
Date: April 8, 2019 Source: University of Zurich Summary: Melting ice sheets in Greenland and the Antarctic as well as ice melt from glaciers all over the world are causing sea levels to rise. Glaciers alone lost more than 9,000 billion tons of ice since 1961, raising water levels by 27 millimeters, an international research team has now found. Share:
Regional share of glaciers in sea-level rise from 1961 to 2016. Credit: Zemp Melting ice sheets in Greenland and the Antarctic as well as ice melt from glaciers all over the world are causing sea levels to rise. Glaciers alone lost more than 9,000 billion tons of ice since 1961, raising water levels by 27 millimeters, an international research team under the lead of the University of Zurich has now found. Glaciers have lost more than 9,000 billion tons (that is 9,625,000,000,000 tons) of ice between 1961 and 2016, which has resulted in global sea levels increasing by 27 millimeters in this period. The largest contributors were glaciers in Alaska, followed by the melting ice fields in Patagonia and glaciers in the Arctic regions. Glaciers in the European Alps, the Caucasus and New Zealand were also subject to significant ice loss; however, due to their relatively small glacierized areas they played only a minor role when it comes to the rising global sea levels. Combination of field observations and satellite measurements For the new study, the international research team combined glaciological field observations with geodetic satellite measurements. The latter digitally measure the surface of the Earth, providing data on ice thickness changes at different points in time. The researchers were thus able to reconstruct changes in the ice thickness of more than 19,000 glaciers worldwide. This was also possible thanks to the comprehensive database compiled by the World Glacier Monitoring Service from its worldwide network of observers, to which the researchers added their own satellite analyses. "By combining these two measurement methods and having the new comprehensive dataset, we can estimate how much ice has been lost each year in all mountain regions since the 1960s," explains Michael Zemp, who led the study. "The glaciological measurements made in the field provide the annual fluctuations, while the satellite data allows us to determine overall ice loss over several years or decades." 335 billion tons of ice lost each year The global mass loss of glacier ice has increased significantly in the last 30 years and currently amounts to 335 billion tons of lost ice each year. This corresponds to an increase in sea levels of almost 1 millimeter per year. "Globally, we lose about three times the ice volume stored in the entirety of the European Alps -- every single year!" says glaciologist Zemp. The melted ice of glaciers therefore accounts for 25 to 30 percent of the current increase in global sea levels. This ice loss of all glaciers roughly corresponds to the mass loss of Greenland's Ice Sheet, and clearly exceeds that of the Antarctic. Story Source: Materials provided by University of Zurich. Note: Content may be edited for style and length. Knight Sha
Date: April 5, 2019 Source: Northumbria University Summary: Glaciology experts have issued evidence that a large section of the Brunt Ice Shelf in Antarctica, which is home to the British Antarctic Survey's Halley Research Station, is about break off. The iceberg, measuring over 1,500 square kilometers -- which is twice the size of New York City -- is expected to break away from the Brunt Ice Shelf within the next few months.
This is the Halloween Crack, which was discovered on 31 October 2016. Credit: Courtesy Jan de Rydt, Northumbria University; British Antarctic Survey Glaciology experts have issued evidence that a large section of the Brunt Ice Shelf in Antarctica, which is home to the British Antarctic Survey's Halley Research Station, is about break off. The rifting started several years ago and is now approaching its final phase. In anticipation of the iceberg breaking away, the research station, which is currently unmanned, has been relocated to a safer location on the ice shelf, meaning there is no danger posed to personnel. The iceberg, measuring over 1,500 square kilometres -- which is twice the size of New York City -- is expected to break away from the Brunt Ice Shelf in as little as a few months, when two large cracks which have been growing over the past seven years meet. Now academics from Northumbria University, in Newcastle upon Tyne, UK, in collaboration with scientists from ENVEO, a remote sensing company in Austria, have submitted new research to the journal The Cryosphere, which shows that the break-off is part of the ice shelf's natural lifecycle, and that similar events may have occurred in the past. As Professor Hilmar Gudmundsson of Northumbria explains: "I have been carrying out research in this area for more than 15 years and have been monitoring the growth of the cracks since they first emerged in 2012. "Satellite images of the changes in the ice shelf have been shared online and there has been much speculation about the cause of this movement and the impact the iceberg will have when it breaks away. "However, what many people do not realise is that this is a natural process and something which has happened time and again. We recognise that climate change is a serious problem which is having an impact around the world, and particularly in the Antarctic. However, there is no indication from our research that this particular event is related to climate change. "We have been tracking the movement of the ice shelf for many years and our modelling indicates that this breakaway is entirely expected. That is why in 2014 we recommended that the Halley Research Station was moved to a new and safe location on the ice shelf. "Our field observations and modelling has meant that the station was safely relocated with no danger to the scientists using it and minimal disruption to the research taking place." The Brunt Ice Shelf is a large floating area of ice, around 150m to 250m thick, and is made up of freshwater ice which originally fell as snow further inland. The ice shelf rests on top of the Weddell Sea and flows off the mainland, moving outwards from the centre of Antarctica. As ice shelves are afloat, any icebergs that form as a result of fractures in the ice do not contribute to sea level rise. "Once the iceberg breaks away from the Brunt Ice Shelf it is likely to drift towards the west and slowly break up into smaller icebergs," explains Dr Jan De Rydt, also of Northumbria University. This isn't the first time a large piece of ice shelf has broken away in Antarctica. The Pine Island Ice Shelf in West Antarctica has seen several large sections break off in recent years, and the Larsen C Ice Shelf to the West of the Brunt Ice Shelf has lost a section more than 3,600 square miles due to calving -- when ice chunks break from the edge of a glacier -- in 2017. And there is historic evidence to show the Brunt Ice Shelf has seen similar large calving events in the past. As Professor Gudmundsson explains: "Maps drawn by Shackleton and Wordie during their expedition to the Brunt Ice Shelf in 1915 show that, at that time, the ice shelf was quite extended. However, by the time the Halley Research Station was established in the 1950s the reach of the ice shelf was much shorter, indicating that a large iceberg must have broken away at some point after 1915. This further backs up our research that this type of event is historically consistent and part of the natural cycle and movement of the ice shelf." Dr De Rydt and Professor Gudmundsson's paper, Calving cycle of the Brunt Ice Shelf, Antarctica, driven by changes in ice-shelf geometry, is currently undergoing peer review in the European Geosciences Union journal The Cryosphere. The paper is co-authored by Thomas Nagler and Jan Wuite of ENVEO (Environmental Earth Observation), in Innsbruck, Austria, who have worked closely with Professor Gudmundsson and Dr De Rydt during the research. ENVEO is a world-leader in processing satellite data for monitoring changes in the global snow and ice cover. The two teams have been collaborating together for several years on a number of projects, with scientists from ENVEO using satellite imagery to extract data about the changing speed of the ice shelf, which is then shared with researchers at Northumbria University for modelling and interpretation. Dr Jan Wuite of ENVEO said: "Thanks to the Copernicus Sentinel-1 and Sentinel-2 satellites we can now continuously monitor the movement of the ice shelf and the propagation of the cracks in great detail and in near real-time. These observational data are very useful for improving existing ice flow models." Dr Thomas Nagler of ENVEO added: "This work is the result of the long-lasting partnership between the glaciologists from Northumbria University and remote sensing experts from ENVEO, that has already led to several previous publications on Brunt Ice Shelf." To view ENVEO's latest images of the Brunt Ice Shelf please visit http://projects.enveo.at/Brunt/ Story Source: Materials provided by Northumbria University. Note: Content may be edited for style and length.
Credit: University of Guelph Warmer temperatures are having a ripple effect on food webs in Ontario lakes, according to a new University of Guelph study. Researchers have found warmer average temperatures over the past decade have forced fish to forage in deeper water. There they hunt different prey species, causing a climate-induced "rewiring" of food webs, altering the flow of energy and nutrients in the lake. Monitoring the movement of generalist species like lake trout may offer an early warning system for impacts of climate change on ecosystems. "We can harness the natural capacity of species to detect and respond to changes in their environment," said Tim Bartley, a post-doc in the Department of Integrative Biology and study lead author. "As species are changing their behaviour, they are telling us about what's happening around them in their environment. We can use this information. The behavioural changes we see imply major reorganization of ecosystems." Published in the journal Nature Ecology and Evolution, the study entailed tracking lake trout movement and feeding in hundreds of lakes in northwestern Ontario. Bartley caught fish to analyze their tissues to see what they ate. The team also used similar data about fish feeding habits and locations across the province from the Ontario Ministry of Natural Resources. Tissue analysis showed that lake trout spend more time in deeper water than near shore, although the researchers were unable to identify specific prey species. Lake trout prefer to catch lake herring; Bartley said trout are flexible feeders that will eat other fish species as well as invertebrates. He said warming may also be pushing lake herring into colder waters, meaning that lake trout may still feed on them in offshore locations. Monitoring behavioural changes in species such as lake trout is important for humans who rely on ecosystems for resources and services from food to water quality, said Bartley. Climate change effects are complicated and vary within ecosystems to create a patchwork of new conditions, he said. Other organisms, including lake trout prey, are also moving in response to warming. Tracking the movement, feeding habits and condition of generalist species such as lake trout may give resource managers an early warning system for detecting the effects of warming. That's important for managing the entire ecosystem and for looking after populations of lake trout, a popular sport fish for anglers, said Bartley. But it's not just happening in lakes. The study also includes data from American researchers showing similar ecosystem "rewiring" in grasslands involving grasshoppers and predatory spiders moving down to cooler areas nearer the soil. The U of G researchers also point to other studies of climate change effects on rewiring of ecosystems involving beluga whales and halibut in Nunavut, polar bears and ringed seals across the Arctic, and Kodiak bears feeding on elderberries and sockeye salmon on the Pacific coast. The report's authors, including integrative biology professors Kevin McCann and Andrew McDougall, concluded: "With further research, we can harness generalists' responses to predict functional outcomes of climate change on the world's ecosystems." Explore further: Researchers find broad impacts from lake trout invasion in Yellowstone More information: Timothy J. Bartley et al, Food web rewiring in a changing world, Nature Ecology & Evolution (2019). DOI: 10.1038/s41559-018-0772-3 Journal reference: Nature Ecology & Evolution Provided by: University of Guelph Knight Man
Date: March 11, 2019 Source: International Center for Tropical Agriculture (CIAT) Summary: By 2040, rainfall on wheat, soybean, rice and maize will have changed, even if Paris Agreement emissions targets are met; projections show parts of Europe, Africa, the Americas and Australia will be drier, while the tropics and north will be wetter.
This infographic shows a selection of areas and crops that will be affected by reduced rainfall in coming decades due to climate change, according to a 2019 study in PNAS. Percentages refer to area of land currently dedicated to cultivation of the specified crops. Credit: Lucelly Anaconas / International Center for Tropical Agriculture (CIAT) Even if humans radically reduce greenhouse gas emissions soon, important crop-growing regions of the world can expect changes to rainfall patterns by 2040. In fact, some regions are already experiencing new climatic regimes compared with just a generation ago. The study, published March 11 in Proceedings of the National Academy of Sciences, warns that up to 14 percent of land dedicated to wheat, maize, rice and soybean will be drier, while up to 31 percent will be wetter. The study uses four emissions scenarios from low to high to predict time of emergence (TOE) of permanent precipitation changes, meaning the year by which precipitation changes remain permanently outside their historical variation in a specific location. The research shows that quick action on emissions -- in line with 2015's Paris Agreement -- would push TOE projections deeper into the future or reduce the size of affected areas. Drier regions include Southwestern Australia, Southern Africa, southwestern South America, and the Mediterranean, according to the study. Wheat cropland in Central Mexico is also headed for a drier future. Wetter areas include Canada, Russia, India and the Eastern United States. The four crops in the study represent about 40 percent of global caloric intake and the authors say that, regardless of how much mitigation is achieved, all regions -- both wetter and drier -- need to invest in adaptation, and do so urgently in areas expected to see major changes in the next couple of decades. However, in the scenarios with low greenhouse gas emissions, most regions have two-three decades more to adapt than under high-emission scenarios. Low-emission scenarios, the authors stressed, likely imply less need for potentially costly adaptation to new rainfall regimes. Wheat under heat Drier conditions are expected for many major wheat producers. In Australia, about 27 percent of wheat-growing land will see less precipitation, under a mid-emissions scenario. Algeria (100 percent), Morocco (91 percent), South Africa (79 percent), Mexico (74 percent), Spain (55 percent), Chile (40 percent), Turkey (28 percent), Italy (20 percent) and Egypt (15 percent) are other major producers that will be affected. Higher emissions mean a larger amount of land will become dry sooner, the study found. "These are definitely countries that will need to think rather quickly what they'd like to do with their wheat production," said Maisa Rojas, the study's lead author and climatologist at Universidad de Chile. Colleagues at the International Center for Tropical Agriculture, the University of Leeds, Chile's Center for Climate and Resilience Research, and Pontificia Universidad Católica de Chile (UC) co-authored the study. "What we're predicting are probably conservative years for time of emergence," said Rojas. "Detectable precipitation changes are of course not only important for agriculture, but for water resource management more in general, so our results are relevant for other sectors as well." Speed of change One stunning aspect of the study is how quickly global precipitation is changing. The baseline for comparison is 20 years spanning 1986-2005. A handful of regions already have crossed that "historical" average into an entirely new rainfall regime, including Russia, Norway, Canada and the parts of the East Coast of the United States. The study projects that up to 36 percent of all land area will be wetter or drier under a high-emission scenario. "Farmers growing crops in those areas are going to experience significantly different conditions than what they are used to," said Julian Ramirez-Villegas, a scientist with the International Center for Tropical Agriculture (CIAT) and the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS). "They're going to be completely outside their normal historical environments and many farmers are already struggling with historic variability." Areas not reflected in the study are likely to have precipitation changes as well, said Rojas. But because natural variation in those areas is high, extreme change is needed before researchers can detect their times of emergence. "Other studies have examined time of emergence in global temperature and precipitation," said Fabrice Lambert, a UC professor and co-author. "The interesting thing about this study is that we overlay the climatic results with spatial cropland distribution and growing seasons to show which agricultural production regions will be impacted by precipitation changes, and how much time they have to prepare." The world's most populous countries -- China and India -- are among those that will have much wetter fields for the four crops included in the study, under any emission scenario. Percentage of cropland that will extend into high double-digits. Asia's other big rice producers, including Japan, Korea and the Philippines will have TOEs for increased rainfall. Wheat fields northern Europe, the United States, Canada and Russia will have higher precipitation. More precipitation may mean higher production, but when coupled with rising sea levels, higher temperatures and increased potential for flooding, higher production is not assured, said the authors. "The precise nature of the changes is impossible to predict," said Andy Challinor, a co-author and Professor at the Priestley International Centre for Climate at the University of Leeds. "What this study tells us is that adaptation needs to be agile. For the first time, we can tell what changes to be ready for -- and when they are expected -- in our major crop-growing regions. Prior to this study, the rainfall changes experienced by crops were thought to be so unpredictable that no real advice could be given." Story Source: Materials provided by International Center for Tropical Agriculture (CIAT). Note: Content may be edited for style and length.
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